A. Guide to CVS commands

This appendix describes the overall structure of CVS commands, and describes some commands in detail (others are described elsewhere; for a quick reference to CVS commands, see section Quick reference to CVS commands).

A.1 Overall structure of CVS commands

The overall format of all CVS commands is:

cvs [ cvs_options ] cvs_command [ command_options ] [ command_args ]

cvs

The name of the CVS program.

cvs_options

Some options that affect all sub-commands of CVS. These are described below.

cvs_command

One of several different sub-commands. Some of the commands have aliases that can be used instead; those aliases are noted in the reference manual for that command. There are only two situations where you may omit `cvs_command': `cvs -H' elicits a list of available commands, and `cvs -v' displays version information on CVS itself.

command_options

Options that are specific for the command.

command_args

Arguments to the commands.

There is unfortunately some confusion between cvs_options and command_options. When given as a cvs_option, some options only affect some of the commands. When given as a command_option it may have a different meaning, and be accepted by more commands. In other words, do not take the above categorization too seriously. Look at the documentation instead.

A.2 CVS's exit status

CVS can indicate to the calling environment whether it succeeded or failed by setting its exit status. The exact way of testing the exit status will vary from one operating system to another. For example in a unix shell script the `$?' variable will be 0 if the last command returned a successful exit status, or greater than 0 if the exit status indicated failure.

If CVS is successful, it returns a successful status; if there is an error, it prints an error message and returns a failure status. The one exception to this is the cvs diff command. It will return a successful status if it found no differences, or a failure status if there were differences or if there was an error. Because this behavior provides no good way to detect errors, in the future it is possible that cvs diff will be changed to behave like the other CVS commands.

A.3 Default options and the ~/.cvsrc file

There are some command_options that are used so often that you might have set up an alias or some other means to make sure you always specify that option. One example (the one that drove the implementation of the `.cvsrc' support, actually) is that many people find the default output of the `diff' command to be very hard to read, and that either context diffs or unidiffs are much easier to understand.

The `~/.cvsrc' file is a way that you can add default options to cvs_commands within cvs, instead of relying on aliases or other shell scripts.

The format of the `~/.cvsrc' file is simple. The file is searched for a line that begins with the same name as the cvs_command being executed. If a match is found, then the remainder of the line is split up (at whitespace characters) into separate options and added to the command arguments before any options from the command line.

If a command has two names (e.g., checkout and co), the official name, not necessarily the one used on the command line, will be used to match against the file. So if this is the contents of the user's `~/.cvsrc' file:

log -N
diff -uN
rdiff -u
update -Pd
checkout -P
release -d

the command `cvs checkout foo' would have the `-P' option added to the arguments, as well as `cvs co foo'.

With the example file above, the output from `cvs diff foobar' will be in unidiff format. `cvs diff -c foobar' will provide context diffs, as usual. Getting "old" format diffs would be slightly more complicated, because diff doesn't have an option to specify use of the "old" format, so you would need `cvs -f diff foobar'.

In place of the command name you can use cvs to specify global options (see section Global options). For example the following line in `.cvsrc'

cvs -z6

causes CVS to use compression level 6.

A.4 Global options

The available `cvs_options' (that are given to the left of `cvs_command') are:

--allow-root=rootdir

May be invoked multiple times to specify one legal CVSROOT directory with each invocation. Also causes CVS to preparse the configuration file for each specified root, which can be useful when configuring write proxies, See Setting up the server for password authentication & Distributing load across several CVS servers.

-a

Authenticate all communication between the client and the server. Only has an effect on the CVS client. As of this writing, this is only implemented when using a GSSAPI connection (see section Direct connection with GSSAPI). Authentication prevents certain sorts of attacks involving hijacking the active TCP connection. Enabling authentication does not enable encryption.

-b bindir

In CVS 1.9.18 and older, this specified that RCS programs are in the bindir directory. Current versions of CVS do not run RCS programs; for compatibility this option is accepted, but it does nothing.

-T tempdir

Use tempdir as the directory where temporary files are located.

The CVS client and server store temporary files in a temporary directory. The path to this temporary directory is set via, in order of precedence:

• The argument to the global `-T' option.
• The value set for TmpDir in the config file (server only - see section The CVSROOT/config configuration file).
• The contents of the $TMPDIR environment variable (%TMPDIR% on Windows - see section All environment variables which affect CVS).
• /tmp

Temporary directories should always be specified as an absolute pathname. When running a CVS client, `-T' affects only the local process; specifying `-T' for the client has no effect on the server and vice versa.

-d cvs_root_directory

Use cvs_root_directory as the root directory pathname of the repository. Overrides the setting of the $CVSROOT environment variable. See section The Repository.

-e editor

Use editor to enter revision log information. Overrides the setting of the $CVSEDITOR and $EDITOR environment variables. For more information, see Committing your changes.

-f

Do not read the `~/.cvsrc' file. This option is most often used because of the non-orthogonality of the CVS option set. For example, the `cvs log' option `-N' (turn off display of tag names) does not have a corresponding option to turn the display on. So if you have `-N' in the `~/.cvsrc' entry for `log', you may need to use `-f' to show the tag names.

-H

--help

Display usage information about the specified `cvs_command' (but do not actually execute the command). If you don't specify a command name, `cvs -H' displays overall help for CVS, including a list of other help options.

-R

Turns on read-only repository mode. This allows one to check out from a read-only repository, such as within an anoncvs server, or from a CD-ROM repository.

Same effect as if the CVSREADONLYFS environment variable is set. Using `-R' can also considerably speed up checkouts over NFS.

-n

Do not change any files. Attempt to execute the `cvs_command', but only to issue reports; do not remove, update, or merge any existing files, or create any new files.

Note that CVS will not necessarily produce exactly the same output as without `-n'. In some cases the output will be the same, but in other cases CVS will skip some of the processing that would have been required to produce the exact same output.

-Q

Cause the command to be really quiet; the command will only generate output for serious problems.

-q

Cause the command to be somewhat quiet; informational messages, such as reports of recursion through subdirectories, are suppressed.

-r

Make new working files read-only. Same effect as if the $CVSREAD environment variable is set (see section All environment variables which affect CVS). The default is to make working files writable, unless watches are on (see section Mechanisms to track who is editing files).

-s variable=value

Set a user variable (see section Expansions in administrative files).

-t

Trace program execution; display messages showing the steps of CVS activity. Particularly useful with `-n' to explore the potential impact of an unfamiliar command.

-v

--version

Display version and copyright information for CVS.

-w

Make new working files read-write. Overrides the setting of the $CVSREAD environment variable. Files are created read-write by default, unless $CVSREAD is set or `-r' is given.

-x

Encrypt all communication between the client and the server. Only has an effect on the CVS client. As of this writing, this is only implemented when using a GSSAPI connection (see section Direct connection with GSSAPI) or a Kerberos connection (see section Direct connection with Kerberos). Enabling encryption implies that message traffic is also authenticated. Encryption support is not available by default; it must be enabled using a special configure option, `--enable-encryption', when you build CVS.

-z level

Request compression level for network traffic. CVS interprets level identically to the gzip program. Valid levels are 1 (high speed, low compression) to 9 (low speed, high compression), or 0 to disable compression (the default). Data sent to the server will be compressed at the requested level and the client will request the server use the same compression level for data returned. The server will use the closest level allowed by the server administrator to compress returned data. This option only has an effect when passed to the CVS client.

A.5 Common command options

This section describes the `command_options' that are available across several CVS commands. These options are always given to the right of `cvs_command'. Not all commands support all of these options; each option is only supported for commands where it makes sense. However, when a command has one of these options you can almost always count on the same behavior of the option as in other commands. (Other command options, which are listed with the individual commands, may have different behavior from one CVS command to the other).

Note: the `history' command is an exception; it supports many options that conflict even with these standard options.

-D date_spec

Use the most recent revision no later than date_spec. date_spec is a single argument, a date description specifying a date in the past.

The specification is sticky when you use it to make a private copy of a source file; that is, when you get a working file using `-D', CVS records the date you specified, so that further updates in the same directory will use the same date (for more information on sticky tags/dates, see section Sticky tags).

`-D' is available with the annotate, checkout, diff, export, history, ls, rdiff, rls, rtag, tag, and update commands. (The history command uses this option in a slightly different way; see section history options).

For a complete description of the date formats accepted by CVS, Date input formats.

Remember to quote the argument to the `-D' flag so that your shell doesn't interpret spaces as argument separators. A command using the `-D' flag can look like this:

$ cvs diff -D "1 hour ago" cvs.texinfo

-f

When you specify a particular date or tag to CVS commands, they normally ignore files that do not contain the tag (or did not exist prior to the date) that you specified. Use the `-f' option if you want files retrieved even when there is no match for the tag or date. (The most recent revision of the file will be used).

Note that even with `-f', a tag that you specify must exist (that is, in some file, not necessary in every file). This is so that CVS will continue to give an error if you mistype a tag name.

`-f' is available with these commands: annotate, checkout, export, rdiff, rtag, and update.

WARNING: The commit and remove commands also have a `-f' option, but it has a different behavior for those commands. See commit options, and Removing files.

-k kflag

Override the default processing of RCS keywords other than `-kb'. See section Keyword substitution, for the meaning of kflag. Used with the checkout and update commands, your kflag specification is sticky; that is, when you use this option with a checkout or update command, CVS associates your selected kflag with any files it operates on, and continues to use that kflag with future commands on the same files until you specify otherwise.

The `-k' option is available with the add, checkout, diff, export, import, rdiff, and update commands.

WARNING: Prior to CVS version 1.12.2, the `-k' flag overrode the `-kb' indication for a binary file. This could sometimes corrupt binary files. See section Merging and keywords, for more.

-l

Local; run only in current working directory, rather than recursing through subdirectories.

Available with the following commands: annotate, checkout, commit, diff, edit, editors, export, log, rdiff, remove, rtag, status, tag, unedit, update, watch, and watchers.

-m message

Use message as log information, instead of invoking an editor.

Available with the following commands: add, commit and import.

-n

Do not run any tag program. (A program can be specified to run in the modules database (see section The modules file); this option bypasses it).

Note: this is not the same as the `cvs -n' program option, which you can specify to the left of a cvs command!

Available with the checkout, commit, export, and rtag commands.

-P

Prune empty directories. See Removing directories.

-p

Pipe the files retrieved from the repository to standard output, rather than writing them in the current directory. Available with the checkout and update commands.

-R

Process directories recursively. This is the default for all CVS commands, with the exception of ls & rls.

Available with the following commands: annotate, checkout, commit, diff, edit, editors, export, ls, rdiff, remove, rls, rtag, status, tag, unedit, update, watch, and watchers.

-r tag

-r tag[:date]

Use the revision specified by the tag argument (and the date argument for the commands which accept it) instead of the default head revision. As well as arbitrary tags defined with the tag or rtag command, two special tags are always available: `HEAD' refers to the most recent version available in the repository, and `BASE' refers to the revision you last checked out into the current working directory.

The tag specification is sticky when you use this with checkout or update to make your own copy of a file: CVS remembers the tag and continues to use it on future update commands, until you specify otherwise (for more information on sticky tags/dates, see section Sticky tags).

The tag can be either a symbolic or numeric tag, as described in Tags–Symbolic revisions, or the name of a branch, as described in Branching and merging. When tag is the name of a branch, some commands accept the optional date argument to specify the revision as of the given date on the branch. When a command expects a specific revision, the name of a branch is interpreted as the most recent revision on that branch.

Specifying the `-q' global option along with the `-r' command option is often useful, to suppress the warning messages when the RCS file does not contain the specified tag.

Note: this is not the same as the overall `cvs -r' option, which you can specify to the left of a CVS command!

`-r tag' is available with the commit and history commands.

`-r tag[:date]' is available with the annotate, checkout, diff, export, rdiff, rtag, and update commands.

-W

Specify file names that should be filtered. You can use this option repeatedly. The spec can be a file name pattern of the same type that you can specify in the `.cvswrappers' file. Available with the following commands: import, and update.

A.6 Date input formats

First, a quote:

Our units of temporal measurement, from seconds on up to months, are so complicated, asymmetrical and disjunctive so as to make coherent mental reckoning in time all but impossible. Indeed, had some tyrannical god contrived to enslave our minds to time, to make it all but impossible for us to escape subjection to sodden routines and unpleasant surprises, he could hardly have done better than handing down our present system. It is like a set of trapezoidal building blocks, with no vertical or horizontal surfaces, like a language in which the simplest thought demands ornate constructions, useless particles and lengthy circumlocutions. Unlike the more successful patterns of language and science, which enable us to face experience boldly or at least level-headedly, our system of temporal calculation silently and persistently encourages our terror of time.

… It is as though architects had to measure length in feet, width in meters and height in ells; as though basic instruction manuals demanded a knowledge of five different languages. It is no wonder then that we often look into our own immediate past or future, last Tuesday or a week from Sunday, with feelings of helpless confusion. …

— Robert Grudin, Time and the Art of Living.

This section describes the textual date representations that GNU programs accept. These are the strings you, as a user, can supply as arguments to the various programs. The C interface (via the get_date function) is not described here.

A.6.1 General date syntax

A date is a string, possibly empty, containing many items separated by whitespace. The whitespace may be omitted when no ambiguity arises. The empty string means the beginning of today (i.e., midnight). Order of the items is immaterial. A date string may contain many flavors of items:

• calendar date items
• time of day items
• time zone items
• day of the week items
• relative items
• pure numbers.

We describe each of these item types in turn, below.

A few ordinal numbers may be written out in words in some contexts. This is most useful for specifying day of the week items or relative items (see below). Among the most commonly used ordinal numbers, the word `last' stands for -1, `this' stands for 0, and `first' and `next' both stand for 1. Because the word `second' stands for the unit of time there is no way to write the ordinal number 2, but for convenience `third' stands for 3, `fourth' for 4, `fifth' for 5, `sixth' for 6, `seventh' for 7, `eighth' for 8, `ninth' for 9, `tenth' for 10, `eleventh' for 11 and `twelfth' for 12.

When a month is written this way, it is still considered to be written numerically, instead of being “spelled in full”; this changes the allowed strings.

In the current implementation, only English is supported for words and abbreviations like `AM', `DST', `EST', `first', `January', `Sunday', `tomorrow', and `year'.

The output of the date command is not always acceptable as a date string, not only because of the language problem, but also because there is no standard meaning for time zone items like `IST'. When using date to generate a date string intended to be parsed later, specify a date format that is independent of language and that does not use time zone items other than `UTC' and `Z'. Here are some ways to do this:

$ LC_ALL=C TZ=UTC0 date
Mon Mar  1 00:21:42 UTC 2004
$ TZ=UTC0 date +'%Y-%m-%d %H:%M:%SZ'
2004-03-01 00:21:42Z
$ date --iso-8601=ns | tr T ' '  # --iso-8601 is a GNU extension.
2004-02-29 16:21:42,692722128-0800
$ date --rfc-2822  # a GNU extension
Sun, 29 Feb 2004 16:21:42 -0800
$ date +'%Y-%m-%d %H:%M:%S %z'  # %z is a GNU extension.
2004-02-29 16:21:42 -0800
$ date +'@%s.%N'  # %s and %N are GNU extensions.
@1078100502.692722128

Alphabetic case is completely ignored in dates. Comments may be introduced between round parentheses, as long as included parentheses are properly nested. Hyphens not followed by a digit are currently ignored. Leading zeros on numbers are ignored.

A.6.2 Calendar date items

A calendar date item specifies a day of the year. It is specified differently, depending on whether the month is specified numerically or literally. All these strings specify the same calendar date:

1972-09-24     # ISO 8601.
72-9-24        # Assume 19xx for 69 through 99,
               # 20xx for 00 through 68.
72-09-24       # Leading zeros are ignored.
9/24/72        # Common U.S. writing.
24 September 1972
24 Sept 72     # September has a special abbreviation.
24 Sep 72      # Three-letter abbreviations always allowed.
Sep 24, 1972
24-sep-72
24sep72

The year can also be omitted. In this case, the last specified year is used, or the current year if none. For example:

9/24
sep 24

Here are the rules.

For numeric months, the ISO 8601 format `year-month-day' is allowed, where year is any positive number, month is a number between 01 and 12, and day is a number between 01 and 31. A leading zero must be present if a number is less than ten. If year is 68 or smaller, then 2000 is added to it; otherwise, if year is less than 100, then 1900 is added to it. The construct `month/day/year', popular in the United States, is accepted. Also `month/day', omitting the year.

Literal months may be spelled out in full: `January', `February', `March', `April', `May', `June', `July', `August', `September', `October', `November' or `December'. Literal months may be abbreviated to their first three letters, possibly followed by an abbreviating dot. It is also permitted to write `Sept' instead of `September'.

When months are written literally, the calendar date may be given as any of the following:

day month year
day month
month day year
day-month-year

Or, omitting the year:

month day

A.6.3 Time of day items

A time of day item in date strings specifies the time on a given day. Here are some examples, all of which represent the same time:

20:02:00.000000
20:02
8:02pm
20:02-0500      # In EST (U.S. Eastern Standard Time).

More generally, the time of day may be given as `hour:minute:second', where hour is a number between 0 and 23, minute is a number between 0 and 59, and second is a number between 0 and 59 possibly followed by `.' or `,' and a fraction containing one or more digits. Alternatively, `:second' can be omitted, in which case it is taken to be zero.

If the time is followed by `am' or `pm' (or `a.m.' or `p.m.'), hour is restricted to run from 1 to 12, and `:minute' may be omitted (taken to be zero). `am' indicates the first half of the day, `pm' indicates the second half of the day. In this notation, 12 is the predecessor of 1: midnight is `12am' while noon is `12pm'. (This is the zero-oriented interpretation of `12am' and `12pm', as opposed to the old tradition derived from Latin which uses `12m' for noon and `12pm' for midnight.)

The time may alternatively be followed by a time zone correction, expressed as `shhmm', where s is `+' or `-', hh is a number of zone hours and mm is a number of zone minutes. You can also separate hh from mm with a colon. When a time zone correction is given this way, it forces interpretation of the time relative to Coordinated Universal Time (UTC), overriding any previous specification for the time zone or the local time zone. For example, `+0530' and `+05:30' both stand for the time zone 5.5 hours ahead of UTC (e.g., India). The minute part of the time of day may not be elided when a time zone correction is used. This is the best way to specify a time zone correction by fractional parts of an hour.

Either `am'/`pm' or a time zone correction may be specified, but not both.

A.6.4 Time zone items

A time zone item specifies an international time zone, indicated by a small set of letters, e.g., `UTC' or `Z' for Coordinated Universal Time. Any included periods are ignored. By following a non-daylight-saving time zone by the string `DST' in a separate word (that is, separated by some white space), the corresponding daylight saving time zone may be specified. Alternatively, a non-daylight-saving time zone can be followed by a time zone correction, to add the two values. This is normally done only for `UTC'; for example, `UTC+05:30' is equivalent to `+05:30'.

Time zone items other than `UTC' and `Z' are obsolescent and are not recommended, because they are ambiguous; for example, `EST' has a different meaning in Australia than in the United States. Instead, it's better to use unambiguous numeric time zone corrections like `-0500', as described in the previous section.

If neither a time zone item nor a time zone correction is supplied, time stamps are interpreted using the rules of the default time zone (see section Specifying time zone rules).

A.6.5 Day of week items

The explicit mention of a day of the week will forward the date (only if necessary) to reach that day of the week in the future.

Days of the week may be spelled out in full: `Sunday', `Monday', `Tuesday', `Wednesday', `Thursday', `Friday' or `Saturday'. Days may be abbreviated to their first three letters, optionally followed by a period. The special abbreviations `Tues' for `Tuesday', `Wednes' for `Wednesday' and `Thur' or `Thurs' for `Thursday' are also allowed.

A number may precede a day of the week item to move forward supplementary weeks. It is best used in expression like `third monday'. In this context, `last day' or `next day' is also acceptable; they move one week before or after the day that day by itself would represent.

A comma following a day of the week item is ignored.

A.6.6 Relative items in date strings

Relative items adjust a date (or the current date if none) forward or backward. The effects of relative items accumulate. Here are some examples:

1 year
1 year ago
3 years
2 days

The unit of time displacement may be selected by the string `year' or `month' for moving by whole years or months. These are fuzzy units, as years and months are not all of equal duration. More precise units are `fortnight' which is worth 14 days, `week' worth 7 days, `day' worth 24 hours, `hour' worth 60 minutes, `minute' or `min' worth 60 seconds, and `second' or `sec' worth one second. An `s' suffix on these units is accepted and ignored.

The unit of time may be preceded by a multiplier, given as an optionally signed number. Unsigned numbers are taken as positively signed. No number at all implies 1 for a multiplier. Following a relative item by the string `ago' is equivalent to preceding the unit by a multiplier with value -1.

The string `tomorrow' is worth one day in the future (equivalent to `day'), the string `yesterday' is worth one day in the past (equivalent to `day ago').

The strings `now' or `today' are relative items corresponding to zero-valued time displacement, these strings come from the fact a zero-valued time displacement represents the current time when not otherwise changed by previous items. They may be used to stress other items, like in `12:00 today'. The string `this' also has the meaning of a zero-valued time displacement, but is preferred in date strings like `this thursday'.

When a relative item causes the resulting date to cross a boundary where the clocks were adjusted, typically for daylight saving time, the resulting date and time are adjusted accordingly.

The fuzz in units can cause problems with relative items. For example, `2003-07-31 -1 month' might evaluate to 2003-07-01, because 2003-06-31 is an invalid date. To determine the previous month more reliably, you can ask for the month before the 15th of the current month. For example:

$ date -R
Thu, 31 Jul 2003 13:02:39 -0700
$ date --date='-1 month' +'Last month was %B?'
Last month was July?
$ date --date="$(date +%Y-%m-15) -1 month" +'Last month was %B!'
Last month was June!

Also, take care when manipulating dates around clock changes such as daylight saving leaps. In a few cases these have added or subtracted as much as 24 hours from the clock, so it is often wise to adopt universal time by setting the TZ environment variable to `UTC0' before embarking on calendrical calculations.

A.6.7 Pure numbers in date strings

The precise interpretation of a pure decimal number depends on the context in the date string.

If the decimal number is of the form yyyymmdd and no other calendar date item (see section Calendar date items) appears before it in the date string, then yyyy is read as the year, mm as the month number and dd as the day of the month, for the specified calendar date.

If the decimal number is of the form hhmm and no other time of day item appears before it in the date string, then hh is read as the hour of the day and mm as the minute of the hour, for the specified time of day. mm can also be omitted.

If both a calendar date and a time of day appear to the left of a number in the date string, but no relative item, then the number overrides the year.

A.6.8 Seconds since the Epoch

If you precede a number with `@', it represents an internal time stamp as a count of seconds. The number can contain an internal decimal point (either `.' or `,'); any excess precision not supported by the internal representation is truncated toward minus infinity. Such a number cannot be combined with any other date item, as it specifies a complete time stamp.

Internally, computer times are represented as a count of seconds since an epoch—a well-defined point of time. On GNU and POSIX systems, the epoch is 1970-01-01 00:00:00 UTC, so `@0' represents this time, `@1' represents 1970-01-01 00:00:01 UTC, and so forth. GNU and most other POSIX-compliant systems support such times as an extension to POSIX, using negative counts, so that `@-1' represents 1969-12-31 23:59:59 UTC.

Traditional Unix systems count seconds with 32-bit two's-complement integers and can represent times from 1901-12-13 20:45:52 through 2038-01-19 03:14:07 UTC. More modern systems use 64-bit counts of seconds with nanosecond subcounts, and can represent all the times in the known lifetime of the universe to a resolution of 1 nanosecond.

On most systems, these counts ignore the presence of leap seconds. For example, on most systems `@915148799' represents 1998-12-31 23:59:59 UTC, `@915148800' represents 1999-01-01 00:00:00 UTC, and there is no way to represent the intervening leap second 1998-12-31 23:59:60 UTC.

A.6.9 Specifying time zone rules

Normally, dates are interpreted using the rules of the current time zone, which in turn are specified by the TZ environment variable, or by a system default if TZ is not set. To specify a different set of default time zone rules that apply just to one date, start the date with a string of the form `TZ="rule"'. The two quote characters (`"') must be present in the date, and any quotes or backslashes within rule must be escaped by a backslash.

For example, with the GNU date command you can answer the question “What time is it in New York when a Paris clock shows 6:30am on October 31, 2004?” by using a date beginning with `TZ="Europe/Paris"' as shown in the following shell transcript:

$ export TZ="America/New_York"
$ date --date='TZ="Europe/Paris" 2004-10-31 06:30'
Sun Oct 31 01:30:00 EDT 2004

In this example, the `--date' operand begins with its own TZ setting, so the rest of that operand is processed according to `Europe/Paris' rules, treating the string `2004-10-31 06:30' as if it were in Paris. However, since the output of the date command is processed according to the overall time zone rules, it uses New York time. (Paris was normally six hours ahead of New York in 2004, but this example refers to a brief Halloween period when the gap was five hours.)

A TZ value is a rule that typically names a location in the `tz' database. A recent catalog of location names appears in the TWiki Date and Time Gateway. A few non-GNU hosts require a colon before a location name in a TZ setting, e.g., `TZ=":America/New_York"'.

The `tz' database includes a wide variety of locations ranging from `Arctic/Longyearbyen' to `Antarctica/South_Pole', but if you are at sea and have your own private time zone, or if you are using a non-GNU host that does not support the `tz' database, you may need to use a POSIX rule instead. Simple POSIX rules like `UTC0' specify a time zone without daylight saving time; other rules can specify simple daylight saving regimes. See (libc)TZ Variable section `Specifying the Time Zone with TZ' in The GNU C Library.

A.6.10 Authors of get_date

get_date was originally implemented by Steven M. Bellovin (smb@research.att.com) while at the University of North Carolina at Chapel Hill. The code was later tweaked by a couple of people on Usenet, then completely overhauled by Rich $alz (rsalz@bbn.com) and Jim Berets (jberets@bbn.com) in August, 1990. Various revisions for the GNU system were made by David MacKenzie, Jim Meyering, Paul Eggert and others.

This chapter was originally produced by François Pinard (pinard@iro.umontreal.ca) from the `getdate.y' source code, and then edited by K. Berry (kb@cs.umb.edu).

A.7 admin—Administration

• Requires: repository, working directory.
• Changes: repository.
• Synonym: rcs

This is the CVS interface to assorted administrative facilities. Some of them have questionable usefulness for CVS but exist for historical purposes. Some of the questionable options are likely to disappear in the future. This command does work recursively, so extreme care should be used.

On unix, if there is a group named cvsadmin, only members of that group can run cvs admin commands, except for those specified using the UserAdminOptions configuration option in the `CVSROOT/config' file. Options specified using UserAdminOptions can be run by any user. See The CVSROOT/config configuration file for more on UserAdminOptions.

The cvsadmin group should exist on the server, or any system running the non-client/server CVS. To disallow cvs admin for all users, create a group with no users in it. On NT, the cvsadmin feature does not exist and all users can run cvs admin.

A.7.1 admin options

Some of these options have questionable usefulness for CVS but exist for historical purposes. Some even make it impossible to use CVS until you undo the effect!

-Aoldfile

Might not work together with CVS. Append the access list of oldfile to the access list of the RCS file.

-alogins

Might not work together with CVS. Append the login names appearing in the comma-separated list logins to the access list of the RCS file.

-b[rev]

Set the default branch to rev. In CVS, you normally do not manipulate default branches; sticky tags (see section Sticky tags) are a better way to decide which branch you want to work on. There is one reason to run cvs admin -b: to revert to the vendor's version when using vendor branches (see section Reverting to the latest vendor release). There can be no space between `-b' and its argument.

-cstring

Sets the comment leader to string. The comment leader is not used by current versions of CVS or RCS 5.7. Therefore, you can almost surely not worry about it. See section Keyword substitution.

-e[logins]

Might not work together with CVS. Erase the login names appearing in the comma-separated list logins from the access list of the RCS file. If logins is omitted, erase the entire access list. There can be no space between `-e' and its argument.

-I

Run interactively, even if the standard input is not a terminal. This option does not work with the client/server CVS and is likely to disappear in a future release of CVS.

-i

Useless with CVS. This creates and initializes a new RCS file, without depositing a revision. With CVS, add files with the cvs add command (see section Adding files to a directory).

-ksubst

Set the default keyword substitution to subst. See section Keyword substitution. Giving an explicit `-k' option to cvs update, cvs export, or cvs checkout overrides this default.

-l[rev]

Lock the revision with number rev. If a branch is given, lock the latest revision on that branch. If rev is omitted, lock the latest revision on the default branch. There can be no space between `-l' and its argument.

This can be used in conjunction with the `rcslock.pl' script in the `contrib' directory of the CVS source distribution to provide reserved checkouts (where only one user can be editing a given file at a time). See the comments in that file for details (and see the `README' file in that directory for disclaimers about the unsupported nature of contrib). According to comments in that file, locking must set to strict (which is the default).

-L

Set locking to strict. Strict locking means that the owner of an RCS file is not exempt from locking for checkin. For use with CVS, strict locking must be set; see the discussion under the `-l' option above.

-mrev:msg

Replace the log message of revision rev with msg.

-Nname[:[rev]]

Act like `-n', except override any previous assignment of name. For use with magic branches, see Magic branch numbers.

-nname[:[rev]]

Associate the symbolic name name with the branch or revision rev. It is normally better to use `cvs tag' or `cvs rtag' instead. Delete the symbolic name if both `:' and rev are omitted; otherwise, print an error message if name is already associated with another number. If rev is symbolic, it is expanded before association. A rev consisting of a branch number followed by a `.' stands for the current latest revision in the branch. A `:' with an empty rev stands for the current latest revision on the default branch, normally the trunk. For example, `cvs admin -nname:' associates name with the current latest revision of all the RCS files; this contrasts with `cvs admin -nname:$' which associates name with the revision numbers extracted from keyword strings in the corresponding working files.

-orange

Deletes (outdates) the revisions given by range.

Note that this command can be quite dangerous unless you know exactly what you are doing (for example see the warnings below about how the rev1:rev2 syntax is confusing).

If you are short on disc this option might help you. But think twice before using it—there is no way short of restoring the latest backup to undo this command! If you delete different revisions than you planned, either due to carelessness or (heaven forbid) a CVS bug, there is no opportunity to correct the error before the revisions are deleted. It probably would be a good idea to experiment on a copy of the repository first.

Specify range in one of the following ways:

rev1::rev2

Collapse all revisions between rev1 and rev2, so that CVS only stores the differences associated with going from rev1 to rev2, not intermediate steps. For example, after `-o 1.3::1.5' one can retrieve revision 1.3, revision 1.5, or the differences to get from 1.3 to 1.5, but not the revision 1.4, or the differences between 1.3 and 1.4. Other examples: `-o 1.3::1.4' and `-o 1.3::1.3' have no effect, because there are no intermediate revisions to remove.

::rev

Collapse revisions between the beginning of the branch containing rev and rev itself. The branchpoint and rev are left intact. For example, `-o ::1.3.2.6' deletes revision 1.3.2.1, revision 1.3.2.5, and everything in between, but leaves 1.3 and 1.3.2.6 intact.

rev::

Collapse revisions between rev and the end of the branch containing rev. Revision rev is left intact but the head revision is deleted.

rev

Delete the revision rev. For example, `-o 1.3' is equivalent to `-o 1.2::1.4'.

rev1:rev2

Delete the revisions from rev1 to rev2, inclusive, on the same branch. One will not be able to retrieve rev1 or rev2 or any of the revisions in between. For example, the command `cvs admin -oR_1_01:R_1_02 .' is rarely useful. It means to delete revisions up to, and including, the tag R_1_02. But beware! If there are files that have not changed between R_1_02 and R_1_03 the file will have the same numerical revision number assigned to the tags R_1_02 and R_1_03. So not only will it be impossible to retrieve R_1_02; R_1_03 will also have to be restored from the tapes! In most cases you want to specify rev1::rev2 instead.

:rev

Delete revisions from the beginning of the branch containing rev up to and including rev.

rev:

Delete revisions from revision rev, including rev itself, to the end of the branch containing rev.

None of the revisions to be deleted may have branches or locks.

If any of the revisions to be deleted have symbolic names, and one specifies one of the `::' syntaxes, then CVS will give an error and not delete any revisions. If you really want to delete both the symbolic names and the revisions, first delete the symbolic names with cvs tag -d, then run cvs admin -o. If one specifies the non-`::' syntaxes, then CVS will delete the revisions but leave the symbolic names pointing to nonexistent revisions. This behavior is preserved for compatibility with previous versions of CVS, but because it isn't very useful, in the future it may change to be like the `::' case.

Due to the way CVS handles branches rev cannot be specified symbolically if it is a branch. See section Magic branch numbers, for an explanation.

Make sure that no-one has checked out a copy of the revision you outdate. Strange things will happen if he starts to edit it and tries to check it back in. For this reason, this option is not a good way to take back a bogus commit; commit a new revision undoing the bogus change instead (see section Merging differences between any two revisions).

-q

Run quietly; do not print diagnostics.

-sstate[:rev]

Useful with CVS. Set the state attribute of the revision rev to state. If rev is a branch number, assume the latest revision on that branch. If rev is omitted, assume the latest revision on the default branch. Any identifier is acceptable for state. A useful set of states is `Exp' (for experimental), `Stab' (for stable), and `Rel' (for released). By default, the state of a new revision is set to `Exp' when it is created. The state is visible in the output from cvs log (see section log—Print out log information for files), and in the `$Log$' and `$State$' keywords (see section Keyword substitution). Note that CVS uses the dead state for its own purposes (see section The attic); to take a file to or from the dead state use commands like cvs remove and cvs add (see section Adding, removing, and renaming files and directories), not cvs admin -s.

-t[file]

Useful with CVS. Write descriptive text from the contents of the named file into the RCS file, deleting the existing text. The file pathname may not begin with `-'. The descriptive text can be seen in the output from `cvs log' (see section log—Print out log information for files). There can be no space between `-t' and its argument.

If file is omitted, obtain the text from standard input, terminated by end-of-file or by a line containing `.' by itself. Prompt for the text if interaction is possible; see `-I'.

-t-string

Similar to `-tfile'. Write descriptive text from the string into the RCS file, deleting the existing text. There can be no space between `-t' and its argument.

-U

Set locking to non-strict. Non-strict locking means that the owner of a file need not lock a revision for checkin. For use with CVS, strict locking must be set; see the discussion under the `-l' option above.

-u[rev]

See the option `-l' above, for a discussion of using this option with CVS. Unlock the revision with number rev. If a branch is given, unlock the latest revision on that branch. If rev is omitted, remove the latest lock held by the caller. Normally, only the locker of a revision may unlock it; somebody else unlocking a revision breaks the lock. This causes the original locker to be sent a commit notification (see section Telling CVS to notify you). There can be no space between `-u' and its argument.

-Vn

In previous versions of CVS, this option meant to write an RCS file which would be acceptable to RCS version n, but it is now obsolete and specifying it will produce an error.

-xsuffixes

In previous versions of CVS, this was documented as a way of specifying the names of the RCS files. However, CVS has always required that the RCS files used by CVS end in `,v', so this option has never done anything useful.

A.8 annotate—What revision modified each line of a file?

• Synopsis: annotate [options] files…
• Requires: repository.
• Changes: nothing.

For each file in files, print the head revision of the trunk, together with information on the last modification for each line.

A.8.1 annotate options

These standard options are supported by annotate (see section Common command options, for a complete description of them):

-l

Local directory only, no recursion.

-R

Process directories recursively.

-f

Use head revision if tag/date not found.

-F

Annotate binary files.

-r tag[:date]

Annotate file as of specified revision/tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. See Common command options.

-D date

Annotate file as of specified date.

A.8.2 annotate example

For example:

$ cvs annotate ssfile
Annotations for ssfile
***************
1.1          (mary     27-Mar-96): ssfile line 1
1.2          (joe      28-Mar-96): ssfile line 2

The file `ssfile' currently contains two lines. The ssfile line 1 line was checked in by mary on March 27. Then, on March 28, joe added a line ssfile line 2, without modifying the ssfile line 1 line. This report doesn't tell you anything about lines which have been deleted or replaced; you need to use cvs diff for that (see section diff—Show differences between revisions).

The options to cvs annotate are listed in Quick reference to CVS commands, and can be used to select the files and revisions to annotate. The options are described in more detail there and in Common command options.

A.9 checkout—Check out sources for editing

• Synopsis: checkout [options] modules…
• Requires: repository.
• Changes: working directory.
• Synonyms: co, get

Create or update a working directory containing copies of the source files specified by modules. You must execute checkout before using most of the other CVS commands, since most of them operate on your working directory.

The modules are either symbolic names for some collection of source directories and files, or paths to directories or files in the repository. The symbolic names are defined in the `modules' file. See section The modules file.

Depending on the modules you specify, checkout may recursively create directories and populate them with the appropriate source files. You can then edit these source files at any time (regardless of whether other software developers are editing their own copies of the sources); update them to include new changes applied by others to the source repository; or commit your work as a permanent change to the source repository.

Note that checkout is used to create directories. The top-level directory created is always added to the directory where checkout is invoked, and usually has the same name as the specified module. In the case of a module alias, the created sub-directory may have a different name, but you can be sure that it will be a sub-directory, and that checkout will show the relative path leading to each file as it is extracted into your private work area (unless you specify the `-Q' global option).

The files created by checkout are created read-write, unless the `-r' option to CVS (see section Global options) is specified, the CVSREAD environment variable is specified (see section All environment variables which affect CVS), or a watch is in effect for that file (see section Mechanisms to track who is editing files).

Note that running checkout on a directory that was already built by a prior checkout is also permitted. This is similar to specifying the `-d' option to the update command in the sense that new directories that have been created in the repository will appear in your work area. However, checkout takes a module name whereas update takes a directory name. Also to use checkout this way it must be run from the top level directory (where you originally ran checkout from), so before you run checkout to update an existing directory, don't forget to change your directory to the top level directory.

For the output produced by the checkout command see update output.

A.9.1 checkout options

These standard options are supported by checkout (see section Common command options, for a complete description of them):

-D date

Use the most recent revision no later than date. This option is sticky, and implies `-P'. See Sticky tags, for more information on sticky tags/dates.

-f

Only useful with the `-D' or `-r' flags. If no matching revision is found, retrieve the most recent revision (instead of ignoring the file).

-k kflag

Process keywords according to kflag. See Keyword substitution. This option is sticky; future updates of this file in this working directory will use the same kflag. The status command can be viewed to see the sticky options. See Quick reference to CVS commands, for more information on the status command.

-l

Local; run only in current working directory.

-n

Do not run any checkout program (as specified with the `-o' option in the modules file; see section The modules file).

-P

Prune empty directories. See Moving and renaming directories.

-p

Pipe files to the standard output.

-R

Checkout directories recursively. This option is on by default.

-r tag[:date]

Checkout the revision specified by tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. This option is sticky, and implies `-P'. See Sticky tags, for more information on sticky tags/dates. Also, see Common command options.

In addition to those, you can use these special command options with checkout:

-A

Reset any sticky tags, dates, or `-k' options. See Sticky tags, for more information on sticky tags/dates.

-c

Copy the module file, sorted, to the standard output, instead of creating or modifying any files or directories in your working directory.

-d dir

Create a directory called dir for the working files, instead of using the module name. In general, using this flag is equivalent to using `mkdir dir; cd dir' followed by the checkout command without the `-d' flag.

There is an important exception, however. It is very convenient when checking out a single item to have the output appear in a directory that doesn't contain empty intermediate directories. In this case only, CVS tries to “shorten” pathnames to avoid those empty directories.

For example, given a module `foo' that contains the file `bar.c', the command `cvs co -d dir foo' will create directory `dir' and place `bar.c' inside. Similarly, given a module `bar' which has subdirectory `baz' wherein there is a file `quux.c', the command `cvs co -d dir bar/baz' will create directory `dir' and place `quux.c' inside.

Using the `-N' flag will defeat this behavior. Given the same module definitions above, `cvs co -N -d dir foo' will create directories `dir/foo' and place `bar.c' inside, while `cvs co -N -d dir bar/baz' will create directories `dir/bar/baz' and place `quux.c' inside.

-j tag

With two `-j' options, merge changes from the revision specified with the first `-j' option to the revision specified with the second `j' option, into the working directory.

With one `-j' option, merge changes from the ancestor revision to the revision specified with the `-j' option, into the working directory. The ancestor revision is the common ancestor of the revision which the working directory is based on, and the revision specified in the `-j' option.

In addition, each -j option can contain an optional date specification which, when used with branches, can limit the chosen revision to one within a specific date. An optional date is specified by adding a colon (:) to the tag: `-jSymbolic_Tag:Date_Specifier'.

See section Branching and merging.

-N

Only useful together with `-d dir'. With this option, CVS will not “shorten” module paths in your working directory when you check out a single module. See the `-d' flag for examples and a discussion.

-s

Like `-c', but include the status of all modules, and sort it by the status string. See section The modules file, for info about the `-s' option that is used inside the modules file to set the module status.

A.9.2 checkout examples

Get a copy of the module `tc':

$ cvs checkout tc

Get a copy of the module `tc' as it looked one day ago:

$ cvs checkout -D yesterday tc

A.10 commit—Check files into the repository

• Synopsis: commit [-lnRf] [-m 'log_message' | -F file] [-r revision] [files…]
• Requires: working directory, repository.
• Changes: repository.
• Synonym: ci

Use commit when you want to incorporate changes from your working source files into the source repository.

If you don't specify particular files to commit, all of the files in your working current directory are examined. commit is careful to change in the repository only those files that you have really changed. By default (or if you explicitly specify the `-R' option), files in subdirectories are also examined and committed if they have changed; you can use the `-l' option to limit commit to the current directory only.

commit verifies that the selected files are up to date with the current revisions in the source repository; it will notify you, and exit without committing, if any of the specified files must be made current first with update (see section update—Bring work tree in sync with repository). commit does not call the update command for you, but rather leaves that for you to do when the time is right.

When all is well, an editor is invoked to allow you to enter a log message that will be written to one or more logging programs (see section The modules file, and see section Loginfo) and placed in the RCS file inside the repository. This log message can be retrieved with the log command; see log—Print out log information for files. You can specify the log message on the command line with the `-m message' option, and thus avoid the editor invocation, or use the `-F file' option to specify that the argument file contains the log message.

At commit, a unique commitid is placed in the RCS file inside the repository. All files committed at once get the same commitid. The commitid can be retrieved with the log and status command; see log—Print out log information for files, File status.

A.10.1 commit options

These standard options are supported by commit (see section Common command options, for a complete description of them):

-l

Local; run only in current working directory.

-R

Commit directories recursively. This is on by default.

-r revision

Commit to revision. revision must be either a branch, or a revision on the main trunk that is higher than any existing revision number (see section Assigning revisions). You cannot commit to a specific revision on a branch.

commit also supports these options:

-c

Refuse to commit files unless the user has registered a valid edit on the file via cvs edit. This is most useful when `commit -c' and `edit -c' have been placed in all `.cvsrc' files. A commit can be forced anyways by either regestering an edit retroactively via cvs edit (no changes to the file will be lost) or using the -f option to commit. Support for commit -c requires both client and a server versions 1.12.10 or greater.

-F file

Read the log message from file, instead of invoking an editor.

-f

Note that this is not the standard behavior of the `-f' option as defined in Common command options.

Force CVS to commit a new revision even if you haven't made any changes to the file. As of CVS version 1.12.10, it also causes the -c option to be ignored. If the current revision of file is 1.7, then the following two commands are equivalent:

$ cvs commit -f file $ cvs commit -r 1.8 file

The `-f' option disables recursion (i.e., it implies `-l'). To force CVS to commit a new revision for all files in all subdirectories, you must use `-f -R'.

-m message

Use message as the log message, instead of invoking an editor.

A.10.2 commit examples

A.10.2.1 Committing to a branch

You can commit to a branch revision (one that has an even number of dots) with the `-r' option. To create a branch revision, use the `-b' option of the rtag or tag commands (see section Branching and merging). Then, either checkout or update can be used to base your sources on the newly created branch. From that point on, all commit changes made within these working sources will be automatically added to a branch revision, thereby not disturbing main-line development in any way. For example, if you had to create a patch to the 1.2 version of the product, even though the 2.0 version is already under development, you might do:

$ cvs rtag -b -r FCS1_2 FCS1_2_Patch product_module
$ cvs checkout -r FCS1_2_Patch product_module
$ cd product_module
[[ hack away ]]
$ cvs commit

This works automatically since the `-r' option is sticky.

A.10.2.2 Creating the branch after editing

Say you have been working on some extremely experimental software, based on whatever revision you happened to checkout last week. If others in your group would like to work on this software with you, but without disturbing main-line development, you could commit your change to a new branch. Others can then checkout your experimental stuff and utilize the full benefit of CVS conflict resolution. The scenario might look like:

[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs update -r EXPR1
$ cvs commit

The update command will make the `-r EXPR1' option sticky on all files. Note that your changes to the files will never be removed by the update command. The commit will automatically commit to the correct branch, because the `-r' is sticky. You could also do like this:

[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs commit -r EXPR1

but then, only those files that were changed by you will have the `-r EXPR1' sticky flag. If you hack away, and commit without specifying the `-r EXPR1' flag, some files may accidentally end up on the main trunk.

To work with you on the experimental change, others would simply do

$ cvs checkout -r EXPR1 whatever_module

A.11 diff—Show differences between revisions

• Synopsis: diff [-lR] [-k kflag] [format_options] [(-r rev1[:date1] | -D date1) [-r rev2[:date2] | -D date2]] [files…]
• Requires: working directory, repository.
• Changes: nothing.

The diff command is used to compare different revisions of files. The default action is to compare your working files with the revisions they were based on, and report any differences that are found.

If any file names are given, only those files are compared. If any directories are given, all files under them will be compared.

The exit status for diff is different than for other CVS commands; for details CVS's exit status.

A.11.1 diff options

These standard options are supported by diff (see section Common command options, for a complete description of them):

-D date

Use the most recent revision no later than date. See `-r' for how this affects the comparison.

-k kflag

Process keywords according to kflag. See Keyword substitution.

-l

Local; run only in current working directory.

-R

Examine directories recursively. This option is on by default.

-r tag[:date]

Compare with revision specified by tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. Zero, one or two `-r' options can be present. With no `-r' option, the working file will be compared with the revision it was based on. With one `-r', that revision will be compared to your current working file. With two `-r' options those two revisions will be compared (and your working file will not affect the outcome in any way).

One or both `-r' options can be replaced by a `-D date' option, described above.

The following options specify the format of the output. They have the same meaning as in GNU diff. Most options have two equivalent names, one of which is a single letter preceded by `-', and the other of which is a long name preceded by `--'.

`-lines'

Show lines (an integer) lines of context. This option does not specify an output format by itself; it has no effect unless it is combined with `-c' or `-u'. This option is obsolete. For proper operation, patch typically needs at least two lines of context.

`-a'

Treat all files as text and compare them line-by-line, even if they do not seem to be text.

`-b'

Ignore trailing white space and consider all other sequences of one or more white space characters to be equivalent.

`-B'

Ignore changes that just insert or delete blank lines.

`--binary'

Read and write data in binary mode.

`--brief'

Report only whether the files differ, not the details of the differences.

`-c'

Use the context output format.

`-C lines'

`--context[=lines]'

Use the context output format, showing lines (an integer) lines of context, or three if lines is not given. For proper operation, patch typically needs at least two lines of context.

`--changed-group-format=format'

Use format to output a line group containing differing lines from both files in if-then-else format. See section Line group formats.

`-d'

Change the algorithm to perhaps find a smaller set of changes. This makes diff slower (sometimes much slower).

`-e'

`--ed'

Make output that is a valid ed script.

`--expand-tabs'

Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files.

`-f'

Make output that looks vaguely like an ed script but has changes in the order they appear in the file.

`-F regexp'

In context and unified format, for each hunk of differences, show some of the last preceding line that matches regexp.

`--forward-ed'

Make output that looks vaguely like an ed script but has changes in the order they appear in the file.

`-H'

Use heuristics to speed handling of large files that have numerous scattered small changes.

`--horizon-lines=lines'

Do not discard the last lines lines of the common prefix and the first lines lines of the common suffix.

`-i'

Ignore changes in case; consider upper- and lower-case letters equivalent.

`-I regexp'

Ignore changes that just insert or delete lines that match regexp.

`--ifdef=name'

Make merged if-then-else output using name.

`--ignore-all-space'

Ignore white space when comparing lines.

`--ignore-blank-lines'

Ignore changes that just insert or delete blank lines.

`--ignore-case'

Ignore changes in case; consider upper- and lower-case to be the same.

`--ignore-matching-lines=regexp'

Ignore changes that just insert or delete lines that match regexp.

`--ignore-space-change'

Ignore trailing white space and consider all other sequences of one or more white space characters to be equivalent.

`--initial-tab'

Output a tab rather than a space before the text of a line in normal or context format. This causes the alignment of tabs in the line to look normal.

`-L label'

Use label instead of the file name in the context format and unified format headers.

`--label=label'

Use label instead of the file name in the context format and unified format headers.

`--left-column'

Print only the left column of two common lines in side by side format.

`--line-format=format'

Use format to output all input lines in if-then-else format. See section Line formats.

`--minimal'

Change the algorithm to perhaps find a smaller set of changes. This makes diff slower (sometimes much slower).

`-n'

Output RCS-format diffs; like `-f' except that each command specifies the number of lines affected.

`-N'

`--new-file'

In directory comparison, if a file is found in only one directory, treat it as present but empty in the other directory.

`--new-group-format=format'

Use format to output a group of lines taken from just the second file in if-then-else format. See section Line group formats.

`--new-line-format=format'

Use format to output a line taken from just the second file in if-then-else format. See section Line formats.

`--old-group-format=format'

Use format to output a group of lines taken from just the first file in if-then-else format. See section Line group formats.

`--old-line-format=format'

Use format to output a line taken from just the first file in if-then-else format. See section Line formats.

`-p'

Show which C function each change is in.

`--rcs'

Output RCS-format diffs; like `-f' except that each command specifies the number of lines affected.

`--report-identical-files'

`-s'

Report when two files are the same.

`--show-c-function'

Show which C function each change is in.

`--show-function-line=regexp'

In context and unified format, for each hunk of differences, show some of the last preceding line that matches regexp.

`--side-by-side'

Use the side by side output format.

`--speed-large-files'

Use heuristics to speed handling of large files that have numerous scattered small changes.

`--suppress-common-lines'

Do not print common lines in side by side format.

`-t'

Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files.

`-T'

Output a tab rather than a space before the text of a line in normal or context format. This causes the alignment of tabs in the line to look normal.

`--text'

Treat all files as text and compare them line-by-line, even if they do not appear to be text.

`-u'

Use the unified output format.

`--unchanged-group-format=format'

Use format to output a group of common lines taken from both files in if-then-else format. See section Line group formats.

`--unchanged-line-format=format'

Use format to output a line common to both files in if-then-else format. See section Line formats.

`-U lines'

`--unified[=lines]'

Use the unified output format, showing lines (an integer) lines of context, or three if lines is not given. For proper operation, patch typically needs at least two lines of context.

`-w'

Ignore white space when comparing lines.

`-W columns'

`--width=columns'

Use an output width of columns in side by side format.

`-y'

Use the side by side output format.

A.11.1.1 Line group formats

Line group formats let you specify formats suitable for many applications that allow if-then-else input, including programming languages and text formatting languages. A line group format specifies the output format for a contiguous group of similar lines.

For example, the following command compares the TeX file `myfile' with the original version from the repository, and outputs a merged file in which old regions are surrounded by `\begin{em}'-`\end{em}' lines, and new regions are surrounded by `\begin{bf}'-`\end{bf}' lines.

cvs diff \
   --old-group-format='\begin{em}
%<\end{em}
' \
   --new-group-format='\begin{bf}
%>\end{bf}
' \
   myfile

The following command is equivalent to the above example, but it is a little more verbose, because it spells out the default line group formats.

cvs diff \
   --old-group-format='\begin{em}
%<\end{em}
' \
   --new-group-format='\begin{bf}
%>\end{bf}
' \
   --unchanged-group-format='%=' \
   --changed-group-format='\begin{em}
%<\end{em}
\begin{bf}
%>\end{bf}
' \
   myfile

Here is a more advanced example, which outputs a diff listing with headers containing line numbers in a “plain English” style.

cvs diff \
   --unchanged-group-format='' \
   --old-group-format='-------- %dn line%(n=1?:s) deleted at %df:
%<' \
   --new-group-format='-------- %dN line%(N=1?:s) added after %de:
%>' \
   --changed-group-format='-------- %dn line%(n=1?:s) changed at %df:
%<-------- to:
%>' \
   myfile

To specify a line group format, use one of the options listed below. You can specify up to four line group formats, one for each kind of line group. You should quote format, because it typically contains shell metacharacters.

`--old-group-format=format'

These line groups are hunks containing only lines from the first file. The default old group format is the same as the changed group format if it is specified; otherwise it is a format that outputs the line group as-is.

`--new-group-format=format'

These line groups are hunks containing only lines from the second file. The default new group format is same as the changed group format if it is specified; otherwise it is a format that outputs the line group as-is.

`--changed-group-format=format'

These line groups are hunks containing lines from both files. The default changed group format is the concatenation of the old and new group formats.

`--unchanged-group-format=format'

These line groups contain lines common to both files. The default unchanged group format is a format that outputs the line group as-is.

In a line group format, ordinary characters represent themselves; conversion specifications start with `%' and have one of the following forms.

`%<'

stands for the lines from the first file, including the trailing newline. Each line is formatted according to the old line format (see section Line formats).

`%>'

stands for the lines from the second file, including the trailing newline. Each line is formatted according to the new line format.

`%='

stands for the lines common to both files, including the trailing newline. Each line is formatted according to the unchanged line format.

`%%'

stands for `%'.

`%c'C''

where C is a single character, stands for C. C may not be a backslash or an apostrophe. For example, `%c':'' stands for a colon, even inside the then-part of an if-then-else format, which a colon would normally terminate.

`%c'\O''

where O is a string of 1, 2, or 3 octal digits, stands for the character with octal code O. For example, `%c'\0'' stands for a null character.

`Fn'

where F is a printf conversion specification and n is one of the following letters, stands for n's value formatted with F.

`e'

The line number of the line just before the group in the old file.

`f'

The line number of the first line in the group in the old file; equals e + 1.

`l'

The line number of the last line in the group in the old file.

`m'

The line number of the line just after the group in the old file; equals l + 1.

`n'

The number of lines in the group in the old file; equals l - f + 1.

`E, F, L, M, N'

Likewise, for lines in the new file.

The printf conversion specification can be `%d', `%o', `%x', or `%X', specifying decimal, octal, lower case hexadecimal, or upper case hexadecimal output respectively. After the `%' the following options can appear in sequence: a `-' specifying left-justification; an integer specifying the minimum field width; and a period followed by an optional integer specifying the minimum number of digits. For example, `%5dN' prints the number of new lines in the group in a field of width 5 characters, using the printf format "%5d".

`(A=B?T:E)'

If A equals B then T else E. A and B are each either a decimal constant or a single letter interpreted as above. This format spec is equivalent to T if A's value equals B's; otherwise it is equivalent to E.

For example, `%(N=0?no:%dN) line%(N=1?:s)' is equivalent to `no lines' if N (the number of lines in the group in the new file) is 0, to `1 line' if N is 1, and to `%dN lines' otherwise.

A.11.1.2 Line formats

Line formats control how each line taken from an input file is output as part of a line group in if-then-else format.

For example, the following command outputs text with a one-column change indicator to the left of the text. The first column of output is `-' for deleted lines, `|' for added lines, and a space for unchanged lines. The formats contain newline characters where newlines are desired on output.

cvs diff \
   --old-line-format='-%l
' \
   --new-line-format='|%l
' \
   --unchanged-line-format=' %l
' \
   myfile

To specify a line format, use one of the following options. You should quote format, since it often contains shell metacharacters.

`--old-line-format=format'

formats lines just from the first file.

`--new-line-format=format'

formats lines just from the second file.

`--unchanged-line-format=format'

formats lines common to both files.

`--line-format=format'

formats all lines; in effect, it sets all three above options simultaneously.

In a line format, ordinary characters represent themselves; conversion specifications start with `%' and have one of the following forms.

`%l'

stands for the contents of the line, not counting its trailing newline (if any). This format ignores whether the line is incomplete.

`%L'

stands for the contents of the line, including its trailing newline (if any). If a line is incomplete, this format preserves its incompleteness.

`%%'

stands for `%'.

`%c'C''

where C is a single character, stands for C. C may not be a backslash or an apostrophe. For example, `%c':'' stands for a colon.

`%c'\O''

where O is a string of 1, 2, or 3 octal digits, stands for the character with octal code O. For example, `%c'\0'' stands for a null character.

`Fn'

where F is a printf conversion specification, stands for the line number formatted with F. For example, `%.5dn' prints the line number using the printf format "%.5d". See section Line group formats, for more about printf conversion specifications.

The default line format is `%l' followed by a newline character.

If the input contains tab characters and it is important that they line up on output, you should ensure that `%l' or `%L' in a line format is just after a tab stop (e.g. by preceding `%l' or `%L' with a tab character), or you should use the `-t' or `--expand-tabs' option.

Taken together, the line and line group formats let you specify many different formats. For example, the following command uses a format similar to diff's normal format. You can tailor this command to get fine control over diff's output.

cvs diff \
   --old-line-format='< %l
' \
   --new-line-format='> %l
' \
   --old-group-format='%df%(f=l?:,%dl)d%dE
%<' \
   --new-group-format='%dea%dF%(F=L?:,%dL)
%>' \
   --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)
%<---
%>' \
   --unchanged-group-format='' \
   myfile

A.11.2 diff examples

The following line produces a Unidiff (`-u' flag) between revision 1.14 and 1.19 of `backend.c'. Due to the `-kk' flag no keywords are substituted, so differences that only depend on keyword substitution are ignored.

$ cvs diff -kk -u -r 1.14 -r 1.19 backend.c

Suppose the experimental branch EXPR1 was based on a set of files tagged RELEASE_1_0. To see what has happened on that branch, the following can be used:

$ cvs diff -r RELEASE_1_0 -r EXPR1

A command like this can be used to produce a context diff between two releases:

$ cvs diff -c -r RELEASE_1_0 -r RELEASE_1_1 > diffs

If you are maintaining ChangeLogs, a command like the following just before you commit your changes may help you write the ChangeLog entry. All local modifications that have not yet been committed will be printed.

$ cvs diff -u | less

A.12 export—Export sources from CVS, similar to checkout

• Synopsis: export [-flNnR] (-r rev[:date] | -D date) [-k subst] [-d dir] module…
• Requires: repository.
• Changes: current directory.

This command is a variant of checkout; use it when you want a copy of the source for module without the CVS administrative directories. For example, you might use export to prepare source for shipment off-site. This command requires that you specify a date or tag (with `-D' or `-r'), so that you can count on reproducing the source you ship to others (and thus it always prunes empty directories).

One often would like to use `-kv' with cvs export. This causes any keywords to be expanded such that an import done at some other site will not lose the keyword revision information. But be aware that doesn't handle an export containing binary files correctly. Also be aware that after having used `-kv', one can no longer use the ident command (which is part of the RCS suite—see ident(1)) which looks for keyword strings. If you want to be able to use ident you must not use `-kv'.

A.12.1 export options

These standard options are supported by export (see section Common command options, for a complete description of them):

-D date

Use the most recent revision no later than date.

-f

If no matching revision is found, retrieve the most recent revision (instead of ignoring the file).

-l

Local; run only in current working directory.

-n

Do not run any checkout program.

-R

Export directories recursively. This is on by default.

-r tag[:date]

Export the revision specified by tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. See Common command options.

In addition, these options (that are common to checkout and export) are also supported:

-d dir

Create a directory called dir for the working files, instead of using the module name. See section checkout options, for complete details on how CVS handles this flag.

-k subst

Set keyword expansion mode (see section Substitution modes).

-N

Only useful together with `-d dir'. See section checkout options, for complete details on how CVS handles this flag.

A.13 history—Show status of files and users

• Synopsis: history [-report] [-flags] [-options args] [files…]
• Requires: the file `$CVSROOT/CVSROOT/history'
• Changes: nothing.

CVS can keep a history log that tracks each use of most CVS commands. You can use history to display this information in various formats.

To enable logging, the `LogHistory' config option must be set to some value other than the empty string and the history file specified by the `HistoryLogPath' option must be writable by all users who may run the CVS executable (see section The CVSROOT/config configuration file).

To enable the history command, logging must be enabled as above and the `HistorySearchPath' config option (see section The CVSROOT/config configuration file) must be set to specify some number of the history logs created thereby and these files must be readable by each user who might run the history command.

Creating a repository via the cvs init command will enable logging of all possible events to a single history log file (`$CVSROOT/CVSROOT/history') with read and write permissions for all users (see section Creating a repository).

Note: history uses `-f', `-l', `-n', and `-p' in ways that conflict with the normal use inside CVS (see section Common command options).

A.13.1 history options

Several options (shown above as `-report') control what kind of report is generated:

-c

Report on each time commit was used (i.e., each time the repository was modified).

-e

Everything (all record types). Equivalent to specifying `-x' with all record types. Of course, `-e' will also include record types which are added in a future version of CVS; if you are writing a script which can only handle certain record types, you'll want to specify `-x'.

-m module

Report on a particular module. (You can meaningfully use `-m' more than once on the command line.)

-o

Report on checked-out modules. This is the default report type.

-T

Report on all tags.

-x type

Extract a particular set of record types type from the CVS history. The types are indicated by single letters, which you may specify in combination.

Certain commands have a single record type:

F

release

O

checkout

E

export

T

rtag

One of five record types may result from an update:

C

A merge was necessary but collisions were detected (requiring manual merging).

G

A merge was necessary and it succeeded.

U

A working file was copied from the repository.

P

A working file was patched to match the repository.

W

The working copy of a file was deleted during update (because it was gone from the repository).

One of three record types results from commit:

A

A file was added for the first time.

M

A file was modified.

R

A file was removed.

The options shown as `-flags' constrain or expand the report without requiring option arguments:

-a

Show data for all users (the default is to show data only for the user executing history).

-l

Show last modification only.

-w

Show only the records for modifications done from the same working directory where history is executing.

The options shown as `-options args' constrain the report based on an argument:

-b str

Show data back to a record containing the string str in either the module name, the file name, or the repository path.

-D date

Show data since date. This is slightly different from the normal use of `-D date', which selects the newest revision older than date.

-f file

Show data for a particular file (you can specify several `-f' options on the same command line). This is equivalent to specifying the file on the command line.

-n module

Show data for a particular module (you can specify several `-n' options on the same command line).

-p repository

Show data for a particular source repository (you can specify several `-p' options on the same command line).

-r rev

Show records referring to revisions since the revision or tag named rev appears in individual RCS files. Each RCS file is searched for the revision or tag.

-t tag

Show records since tag tag was last added to the history file. This differs from the `-r' flag above in that it reads only the history file, not the RCS files, and is much faster.

-u name

Show records for user name.

-z timezone

Show times in the selected records using the specified time zone instead of UTC.

A.14 import—Import sources into CVS, using vendor branches

• Synopsis: import [-options] repository vendortag releasetag…
• Requires: Repository, source distribution directory.
• Changes: repository.

Use import to incorporate an entire source distribution from an outside source (e.g., a source vendor) into your source repository directory. You can use this command both for initial creation of a repository, and for wholesale updates to the module from the outside source. See section Tracking third-party sources, for a discussion on this subject.

The repository argument gives a directory name (or a path to a directory) under the CVS root directory for repositories; if the directory did not exist, import creates it.

When you use import for updates to source that has been modified in your source repository (since a prior import), it will notify you of any files that conflict in the two branches of development; use `checkout -j' to reconcile the differences, as import instructs you to do.

If CVS decides a file should be ignored (see section Ignoring files via cvsignore), it does not import it and prints `I ' followed by the filename (see section import output, for a complete description of the output).

If the file `$CVSROOT/CVSROOT/cvswrappers' exists, any file whose names match the specifications in that file will be treated as packages and the appropriate filtering will be performed on the file/directory before being imported. See section The cvswrappers file.

The outside source is saved in a first-level branch, by default 1.1.1. Updates are leaves of this branch; for example, files from the first imported collection of source will be revision 1.1.1.1, then files from the first imported update will be revision 1.1.1.2, and so on.

At least three arguments are required. repository is needed to identify the collection of source. vendortag is a tag for the entire branch (e.g., for 1.1.1). You must also specify at least one releasetag to uniquely identify the files at the leaves created each time you execute import. The releasetag should be new, not previously existing in the repository file, and uniquely identify the imported release,

Note that import does not change the directory in which you invoke it. In particular, it does not set up that directory as a CVS working directory; if you want to work with the sources import them first and then check them out into a different directory (see section Getting the source).

A.14.1 import options

This standard option is supported by import (see section Common command options, for a complete description):

-m message

Use message as log information, instead of invoking an editor.

There are the following additional special options.

-b branch

See Multiple vendor branches.

-k subst

Indicate the keyword expansion mode desired. This setting will apply to all files created during the import, but not to any files that previously existed in the repository. See Substitution modes, for a list of valid `-k' settings.

-I name

Specify file names that should be ignored during import. You can use this option repeatedly. To avoid ignoring any files at all (even those ignored by default), specify `-I !'.

name can be a file name pattern of the same type that you can specify in the `.cvsignore' file. See section Ignoring files via cvsignore.

-W spec

Specify file names that should be filtered during import. You can use this option repeatedly.

spec can be a file name pattern of the same type that you can specify in the `.cvswrappers' file. See section The cvswrappers file.

-X

Modify the algorithm used by CVS when importing new files so that new files do not immediately appear on the main trunk.

Specifically, this flag causes CVS to mark new files as if they were deleted on the main trunk, by taking the following steps for each file in addition to those normally taken on import: creating a new revision on the main trunk indicating that the new file is dead, resetting the new file's default branch, and placing the file in the Attic (see section The attic) directory.

Use of this option can be forced on a repository-wide basis by setting the `ImportNewFilesToVendorBranchOnly' option in CVSROOT/config (see section The CVSROOT/config configuration file).

A.14.2 import output

import keeps you informed of its progress by printing a line for each file, preceded by one character indicating the status of the file:

U file

The file already exists in the repository and has not been locally modified; a new revision has been created (if necessary).

N file

The file is a new file which has been added to the repository.

C file

The file already exists in the repository but has been locally modified; you will have to merge the changes.

I file

The file is being ignored (see section Ignoring files via cvsignore).

L file

The file is a symbolic link; cvs import ignores symbolic links. People periodically suggest that this behavior should be changed, but if there is a consensus on what it should be changed to, it is not apparent. (Various options in the `modules' file can be used to recreate symbolic links on checkout, update, etc.; see section The modules file.)

A.14.3 import examples

See Tracking third-party sources, and Creating a directory tree from a number of files.

A.15 log—Print out log information for files

• Synopsis: log [options] [files…]
• Requires: repository, working directory.
• Changes: nothing.

Display log information for files. log used to call the RCS utility rlog. Although this is no longer true in the current sources, this history determines the format of the output and the options, which are not quite in the style of the other CVS commands.

The output includes the location of the RCS file, the head revision (the latest revision on the trunk), all symbolic names (tags) and some other things. For each revision, the revision number, the date, the author, the number of lines added/deleted, the commitid and the log message are printed. All dates are displayed in local time at the client. This is typically specified in the $TZ environment variable, which can be set to govern how log displays dates.

Note: log uses `-R' in a way that conflicts with the normal use inside CVS (see section Common command options).

A.15.1 log options

By default, log prints all information that is available. All other options restrict the output. Note that the revision selection options (-d, -r, -s, and -w) have no effect, other than possibly causing a search for files in Attic directories, when used in conjunction with the options that restrict the output to only log header fields (-b, -h, -R, and -t) unless the -S option is also specified.

-b

Print information about the revisions on the default branch, normally the highest branch on the trunk.

-d dates

Print information about revisions with a checkin date/time in the range given by the semicolon-separated list of dates. The date formats accepted are those accepted by the `-D' option to many other CVS commands (see section Common command options). Dates can be combined into ranges as follows:

d1<d2

d2>d1

Select the revisions that were deposited between d1 and d2.

<d

d>

Select all revisions dated d or earlier.

d<

>d

Select all revisions dated d or later.

d

Select the single, latest revision dated d or earlier.

The `>' or `<' characters may be followed by `=' to indicate an inclusive range rather than an exclusive one.

Note that the separator is a semicolon (;).

-h

Print only the name of the RCS file, name of the file in the working directory, head, default branch, access list, locks, symbolic names, and suffix.

-l

Local; run only in current working directory. (Default is to run recursively).

-N

Do not print the list of tags for this file. This option can be very useful when your site uses a lot of tags, so rather than "more"'ing over 3 pages of tag information, the log information is presented without tags at all.

-R

Print only the name of the RCS file.

-rrevisions

Print information about revisions given in the comma-separated list revisions of revisions and ranges. The following table explains the available range formats:

rev1:rev2

Revisions rev1 to rev2 (which must be on the same branch).

rev1::rev2

The same, but excluding rev1.

:rev

::rev

Revisions from the beginning of the branch up to and including rev.

rev:

Revisions starting with rev to the end of the branch containing rev.

rev::

Revisions starting just after rev to the end of the branch containing rev.

branch

An argument that is a branch means all revisions on that branch.

branch1:branch2

branch1::branch2

A range of branches means all revisions on the branches in that range.

branch.

The latest revision in branch.

A bare `-r' with no revisions means the latest revision on the default branch, normally the trunk. There can be no space between the `-r' option and its argument.

-S

Suppress the header if no revisions are selected.

-s states

Print information about revisions whose state attributes match one of the states given in the comma-separated list states. Individual states may be any text string, though CVS commonly only uses two states, `Exp' and `dead'. See admin options for more information.

-t

Print the same as `-h', plus the descriptive text.

-wlogins

Print information about revisions checked in by users with login names appearing in the comma-separated list logins. If logins is omitted, the user's login is assumed. There can be no space between the `-w' option and its argument.

log prints the intersection of the revisions selected with the options `-d', `-s', and `-w', intersected with the union of the revisions selected by `-b' and `-r'.

A.15.2 log examples

Since log shows dates in local time, you might want to see them in Coordinated Universal Time (UTC) or some other timezone. To do this you can set your $TZ environment variable before invoking CVS:

$ TZ=UTC cvs log foo.c
$ TZ=EST cvs log bar.c

(If you are using a csh-style shell, like tcsh, you would need to prefix the examples above with env.)

A.16 ls & rls

• ls [-e | -l] [-RP] [-r tag[:date]] [-D date] [path…]
• Requires: repository for rls, repository & working directory for ls.
• Changes: nothing.
• Synonym: dir & list are synonyms for ls and rdir & rlist are synonyms for rls.

The ls and rls commands are used to list files and directories in the repository.

By default ls lists the files and directories that belong in your working directory, what would be there after an update.

By default rls lists the files and directories on the tip of the trunk in the topmost directory of the repository.

Both commands accept an optional list of file and directory names, relative to the working directory for ls and the topmost directory of the repository for rls. Neither is recursive by default.

A.16.1 ls & rls options

These standard options are supported by ls & rls:

-d

Show dead revisions (with tag when specified).

-e

Display in CVS/Entries format. This format is meant to remain easily parsable by automation.

-l

Display all details.

-P

Don't list contents of empty directories when recursing.

-R

List recursively.

-r tag[:date]

Show files specified by tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. See Common command options.

-D date

Show files from date.

A.16.2 rls examples

$ cvs rls
cvs rls: Listing module: `.'
CVSROOT
first-dir

$ cvs rls CVSROOT
cvs rls: Listing module: `CVSROOT'
checkoutlist
commitinfo
config
cvswrappers
loginfo
modules
notify
rcsinfo
taginfo
verifymsg

A.17 rdiff—'patch' format diffs between releases

• rdiff [-flags] [-V vn] (-r tag1[:date1] | -D date1) [-r tag2[:date2] | -D date2] modules…
• Requires: repository.
• Changes: nothing.
• Synonym: patch

Builds a Larry Wall format patch(1) file between two releases, that can be fed directly into the patch program to bring an old release up-to-date with the new release. (This is one of the few CVS commands that operates directly from the repository, and doesn't require a prior checkout.) The diff output is sent to the standard output device.

You can specify (using the standard `-r' and `-D' options) any combination of one or two revisions or dates. If only one revision or date is specified, the patch file reflects differences between that revision or date and the current head revisions in the RCS file.

Note that if the software release affected is contained in more than one directory, then it may be necessary to specify the `-p' option to the patch command when patching the old sources, so that patch is able to find the files that are located in other directories.

A.17.1 rdiff options

These standard options are supported by rdiff (see section Common command options, for a complete description of them):

-D date

Use the most recent revision no later than date.

-f

If no matching revision is found, retrieve the most recent revision (instead of ignoring the file).

-k kflag

Process keywords according to kflag. See Keyword substitution.

-l

Local; don't descend subdirectories.

-R

Examine directories recursively. This option is on by default.

-r tag

Use the revision specified by tag, or when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. See Common command options.

In addition to the above, these options are available:

-c

Use the context diff format. This is the default format.

-s

Create a summary change report instead of a patch. The summary includes information about files that were changed or added between the releases. It is sent to the standard output device. This is useful for finding out, for example, which files have changed between two dates or revisions.

-t

A diff of the top two revisions is sent to the standard output device. This is most useful for seeing what the last change to a file was.

-u

Use the unidiff format for the context diffs. Remember that old versions of the patch program can't handle the unidiff format, so if you plan to post this patch to the net you should probably not use `-u'.

-V vn

Expand keywords according to the rules current in RCS version vn (the expansion format changed with RCS version 5). Note that this option is no longer accepted. CVS will always expand keywords the way that RCS version 5 does.

A.17.2 rdiff examples

Suppose you receive mail from foo@example.net asking for an update from release 1.2 to 1.4 of the tc compiler. You have no such patches on hand, but with CVS that can easily be fixed with a command such as this:

$ cvs rdiff -c -r FOO1_2 -r FOO1_4 tc | \
$$ Mail -s 'The patches you asked for' foo@example.net

Suppose you have made release 1.3, and forked a branch called `R_1_3fix' for bug fixes. `R_1_3_1' corresponds to release 1.3.1, which was made some time ago. Now, you want to see how much development has been done on the branch. This command can be used:

$ cvs patch -s -r R_1_3_1 -r R_1_3fix module-name
cvs rdiff: Diffing module-name
File ChangeLog,v changed from revision 1.52.2.5 to 1.52.2.6
File foo.c,v changed from revision 1.52.2.3 to 1.52.2.4
File bar.h,v changed from revision 1.29.2.1 to 1.2

A.18 release—Indicate that a Module is no longer in use

• release [-d] directories…
• Requires: Working directory.
• Changes: Working directory, history log.

This command is meant to safely cancel the effect of `cvs checkout'. Since CVS doesn't lock files, it isn't strictly necessary to use this command. You can always simply delete your working directory, if you like; but you risk losing changes you may have forgotten, and you leave no trace in the CVS history file (see section The history file) that you've abandoned your checkout.

Use `cvs release' to avoid these problems. This command checks that no uncommitted changes are present; that you are executing it from immediately above a CVS working directory; and that the repository recorded for your files is the same as the repository defined in the module database.

If all these conditions are true, `cvs release' leaves a record of its execution (attesting to your intentionally abandoning your checkout) in the CVS history log.

A.18.1 release options

The release command supports one command option:

-d

Delete your working copy of the file if the release succeeds. If this flag is not given your files will remain in your working directory.

WARNING: The release command deletes all directories and files recursively. This has the very serious side-effect that any directory that you have created inside your checked-out sources, and not added to the repository (using the add command; see section Adding files to a directory) will be silently deleted—even if it is non-empty!

A.18.2 release output

Before release releases your sources it will print a one-line message for any file that is not up-to-date.

U file

P file

There exists a newer revision of this file in the repository, and you have not modified your local copy of the file (`U' and `P' mean the same thing).

A file

The file has been added to your private copy of the sources, but has not yet been committed to the repository. If you delete your copy of the sources this file will be lost.

R file

The file has been removed from your private copy of the sources, but has not yet been removed from the repository, since you have not yet committed the removal. See section commit—Check files into the repository.

M file

The file is modified in your working directory. There might also be a newer revision inside the repository.

? file

file is in your working directory, but does not correspond to anything in the source repository, and is not in the list of files for CVS to ignore (see the description of the `-I' option, and see section Ignoring files via cvsignore). If you remove your working sources, this file will be lost.

A.18.3 release examples

Release the `tc' directory, and delete your local working copy of the files.

$ cd ..         # You must stand immediately above the
                # sources when you issue `cvs release'.
$ cvs release -d tc
You have [0] altered files in this repository.
Are you sure you want to release (and delete) directory `tc': y
$

A.19 server & pserver—Act as a server for a client on stdin/stdout

• pserver [-c path]

  server [-c path]

• Requires: repository, client conversation on stdin/stdout
• Changes: Repository or, indirectly, client working directory.

The CVS server and pserver commands are used to provide repository access to remote clients and expect a client conversation on stdin & stdout. Typically these commands are launched from inetd or via ssh (see section Remote repositories).

server expects that the client has already been authenticated somehow, typically via SSH, and pserver attempts to authenticate the client itself.

Only one option is available with the server and pserver commands:

-c path

Load configuration from path rather than the default location `$CVSROOT/CVSROOT/config' (see section The CVSROOT/config configuration file). path must be `/etc/cvs.conf' or prefixed by `/etc/cvs/'. This option is supported beginning with CVS release 1.12.13.

A.20 update—Bring work tree in sync with repository

• update [-ACdflPpR] [-I name] [-j rev [-j rev]] [-k kflag] [-r tag[:date] | -D date] [-W spec] files…
• Requires: repository, working directory.
• Changes: working directory.

After you've run checkout to create your private copy of source from the common repository, other developers will continue changing the central source. From time to time, when it is convenient in your development process, you can use the update command from within your working directory to reconcile your work with any revisions applied to the source repository since your last checkout or update. Without the -C option, update will also merge any differences between the local copy of files and their base revisions into any destination revisions specified with -r, -D, or -A.

A.20.1 update options

These standard options are available with update (see section Common command options, for a complete description of them):

-D date

Use the most recent revision no later than date. This option is sticky, and implies `-P'. See Sticky tags, for more information on sticky tags/dates.

-f

Only useful with the `-D' or `-r' flags. If no matching revision is found, retrieve the most recent revision (instead of ignoring the file).

-k kflag

Process keywords according to kflag. See Keyword substitution. This option is sticky; future updates of this file in this working directory will use the same kflag. The status command can be viewed to see the sticky options. See Quick reference to CVS commands, for more information on the status command.

-l

Local; run only in current working directory. See section Recursive behavior.

-P

Prune empty directories. See Moving and renaming directories.

-p

Pipe files to the standard output.

-R

Update directories recursively (default). See section Recursive behavior.

-r tag[:date]

Retrieve the revisions specified by tag or, when date is specified and tag is a branch tag, the version from the branch tag as it existed on date. This option is sticky, and implies `-P'. See Sticky tags, for more information on sticky tags/dates. Also see Common command options.

These special options are also available with update.

-A

Reset any sticky tags, dates, or `-k' options. See Sticky tags, for more information on sticky tags/dates.

-C

Overwrite locally modified files with clean copies from the repository (the modified file is saved in `.#file.revision', however).

-d

Create any directories that exist in the repository if they're missing from the working directory. Normally, update acts only on directories and files that were already enrolled in your working directory.

This is useful for updating directories that were created in the repository since the initial checkout; but it has an unfortunate side effect. If you deliberately avoided certain directories in the repository when you created your working directory (either through use of a module name or by listing explicitly the files and directories you wanted on the command line), then updating with `-d' will create those directories, which may not be what you want.

-I name

Ignore files whose names match name (in your working directory) during the update. You can specify `-I' more than once on the command line to specify several files to ignore. Use `-I !' to avoid ignoring any files at all. See section Ignoring files via cvsignore, for other ways to make CVS ignore some files.

-Wspec

Specify file names that should be filtered during update. You can use this option repeatedly.

spec can be a file name pattern of the same type that you can specify in the `.cvswrappers' file. See section The cvswrappers file.

-jrevision

With two `-j' options, merge changes from the revision specified with the first `-j' option to the revision specified with the second `j' option, into the working directory.

With one `-j' option, merge changes from the ancestor revision to the revision specified with the `-j' option, into the working directory. The ancestor revision is the common ancestor of the revision which the working directory is based on, and the revision specified in the `-j' option.

Note that using a single `-j tagname' option rather than `-j branchname' to merge changes from a branch will often not remove files which were removed on the branch. See section Merging can add or remove files, for more.

In addition, each `-j' option can contain an optional date specification which, when used with branches, can limit the chosen revision to one within a specific date. An optional date is specified by adding a colon (:) to the tag: `-jSymbolic_Tag:Date_Specifier'.

See section Branching and merging.

A.20.2 update output

update and checkout keep you informed of their progress by printing a line for each file, preceded by one character indicating the status of the file:

U file

The file was brought up to date with respect to the repository. This is done for any file that exists in the repository but not in your working directory, and for files that you haven't changed but are not the most recent versions available in the repository.

P file

Like `U', but the CVS server sends a patch instead of an entire file. This accomplishes the same thing as `U' using less bandwidth.

A file

The file has been added to your private copy of the sources, and will be added to the source repository when you run commit on the file. This is a reminder to you that the file needs to be committed.

R file

The file has been removed from your private copy of the sources, and will be removed from the source repository when you run commit on the file. This is a reminder to you that the file needs to be committed.

M file

The file is modified in your working directory.

`M' can indicate one of two states for a file you're working on: either there were no modifications to the same file in the repository, so that your file remains as you last saw it; or there were modifications in the repository as well as in your copy, but they were merged successfully, without conflict, in your working directory.

CVS will print some messages if it merges your work, and a backup copy of your working file (as it looked before you ran update) will be made. The exact name of that file is printed while update runs.

C file

A conflict was detected while trying to merge your changes to file with changes from the source repository. file (the copy in your working directory) is now the result of attempting to merge the two revisions; an unmodified copy of your file is also in your working directory, with the name `.#file.revision' where revision is the revision that your modified file started from. Resolve the conflict as described in Conflicts example. (Note that some systems automatically purge files that begin with `.#' if they have not been accessed for a few days. If you intend to keep a copy of your original file, it is a very good idea to rename it.) Under VMS, the file name starts with `__' rather than `.#'.

? file

file is in your working directory, but does not correspond to anything in the source repository, and is not in the list of files for CVS to ignore (see the description of the `-I' option, and see section Ignoring files via cvsignore).

This document was generated by Derek R. Price on October, 3 2005 using texi2html 1.77.