--- name: "rcs" section: "1" platform: "linux" package: "rcs" version: "5.10.1-3" release: "Arch Linux 2026-11-01" platforms: ["linux", "openbsd"] url: "https://new.carta.tech/rcs" --- # rcs(1) change RCS file attributes ## NAME rcs - change RCS file attributes ## SYNOPSIS **rcs** *options file* ... ## DESCRIPTION **rcs** creates new RCS files or changes attributes of existing ones. An RCS file contains multiple revisions of text, an access list, a change log, descriptive text, and some control attributes. For **rcs** to work, the caller's login name must be on the access list, except if the access list is empty, the caller is the owner of the file or the superuser, or the **-i** option is present. Filenames matching an RCS suffix denote RCS files; all others denote working files. Names are paired as explained in [**ci**(1)](/ci/1.md). Revision numbers use the syntax described in [**ci**(1)](/ci/1.md). ## OPTIONS - **-i** Create and initialize a new RCS file, but do not deposit any revision. If the RCS file name has no directory component, try to place it first into the subdirectory **./RCS**, and then into the current directory. If the RCS file already exists, print an error message. - **-a***logins* Append the login names appearing in the comma-separated list *logins* to the access list of the RCS file. - **-A***oldfile* Append the access list of *oldfile* to the access list of the RCS file. - **-e**\[*logins*\] 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. - **-b**\[*rev*\] Set the default branch to *rev*. If *rev* is omitted, the default branch is reset to the (dynamically) highest branch on the trunk. - **-c***string* Set the comment leader to *string*. An initial **ci**, or an **rcs -i** without **-c**, guesses the comment leader from the suffix of the working file name. This option is obsolescent, since RCS normally uses the preceding **$Log$** line's prefix when inserting log lines during checkout (see [**co**(1)](/co/1.md)). However, older versions of RCS use the comment leader instead of the **$Log$** line's prefix, so if you plan to access a file with both old and new versions of RCS, make sure its comment leader matches its **$Log$** line prefix. - **-k***subst* Set the default keyword substitution to *subst*. The effect of keyword substitution is described in [**co**(1)](/co/1.md). Giving an explicit **-k** option to **co**, **rcsdiff**, and **rcsmerge** overrides this default. Beware **rcs -kv**, because **-kv** is incompatible with **co -l**. Use **rcs -kkv** to restore the normal default keyword substitution. - **-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. Locking prevents overlapping changes. If someone else already holds the lock, the lock is broken as with **rcs -u** (see below). - **-u**\[*rev*\] 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 can unlock it. Somebody else unlocking a revision breaks the lock. If RCS was configured **--with-mailer**, then this causes a mail message to be sent to the original locker. The message contains a commentary solicited from the breaker. The commentary is terminated by end-of-file or by a line containing **.** by itself. - **-L** Set locking to *strict*. Strict locking means that the owner of an RCS file is not exempt from locking for checkin. This option should be used for files that are shared. - **-U** Set locking to non-strict. Non-strict locking means that the owner of a file need not lock a revision for checkin. This option should *not* be used for files that are shared. Whether default locking is strict is determined by your system administrator, but it is normally strict. - **-m***rev***:**\[*msg*\] Replace revision *rev*'s log message with *msg*. If *msg* is omitted, it defaults to "\*\*\* empty log message \*\*\*". - **-M** Do not send mail when breaking somebody else's lock. This option is not meant for casual use; it is meant for programs that warn users by other means, and invoke **rcs -u** only as a low-level lock-breaking operation. - **-n***name*\[**:**\[*rev*\]\] Associate the symbolic name *name* with the branch or revision *rev*. 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, **rcs -n***name***: RCS/\*** associates *name* with the current latest revision of all the named RCS files; this contrasts with **rcs -n***name***:$ RCS/\*** which associates *name* with the revision numbers extracted from keyword strings in the corresponding working files. - **-N***name*\[**:**\[*rev*\]\] Act like **-n**, except override any previous assignment of *name*. - **-o***range* deletes (“outdates”) the revisions given by *range*. A range consisting of a single revision number means that revision. A range consisting of a branch number means the latest revision on that branch. A range of the form *rev1***:***rev2* means revisions *rev1* to *rev2* on the same branch, **:***rev* means from the beginning of the branch containing *rev* up to and including *rev*, and *rev***:** means from revision *rev* to the end of the branch containing *rev*. None of the outdated revisions can have branches or locks. - **-q** Run quietly; do not print diagnostics. - **-I** Run interactively, even if the standard input is not a terminal. - **-s*state*\[:*rev*\]** 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, [**ci**(1)](/ci/1.md) sets the state of a revision to **Exp**. - **-t**\[*file*\] Write descriptive text from the contents of the named *file* into the RCS file, deleting the existing text. The *file* name cannot begin with **-**. 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**. With **-i**, descriptive text is obtained even if **-t** is not given. - **-t-***string* Write descriptive text from the *string* into the RCS file, deleting the existing text. - **-T** Preserve the modification time on the RCS file unless a revision is removed. This option can suppress extensive recompilation caused by a [**make**(1)](/make/1.md) dependency of some copy of the working file on the RCS file. Use this option with care; it can suppress recompilation even when it is needed, i.e. when a change to the RCS file would mean a change to keyword strings in the working file. - **-V** Print RCS's version number. - **-V***n* Emulate RCS version *n*. See [**co**(1)](/co/1.md) for details. - **-x***suffixes* Use *suffixes* to characterize RCS files. See [**ci**(1)](/ci/1.md) for details. - **-z***zone* Use *zone* as the default time zone. This option has no effect; it is present for compatibility with other RCS commands. At least one explicit option must be given, to ensure compatibility with future planned extensions to the **rcs** command. ## COMPATIBILITY The **-b***rev* option generates an RCS file that cannot be parsed by RCS version 3 or earlier. The **-k***subst* options (except **-kkv**) generate an RCS file that cannot be parsed by RCS version 4 or earlier. Use **rcs -V***n* to make an RCS file acceptable to RCS version *n* by discarding information that would confuse version *n*. RCS version 5.5 and earlier does not support the **-x** option, and requires a **,v** suffix on an RCS file name. ## FILES **rcs** accesses files much as [**ci**(1)](/ci/1.md) does, except that it uses the effective user for all accesses, it does not write the working file or its directory, and it does not even read the working file unless a revision number of **$** is specified. ## ENVIRONMENT - **RCSINIT** Options prepended to the argument list, separated by spaces. A backslash escapes spaces within an option. The **RCSINIT** options are prepended to the argument lists of most RCS commands. Useful **RCSINIT** options include **-q**, **-V**, **-x**, and **-z**. - **RCS\_MEM\_LIMIT** Normally, for speed, commands either memory map or copy into memory the RCS file if its size is less than the *memory-limit*, currently defaulting to \`\`unlimited''. Otherwise (or if the initially-tried speedy ways fail), the commands fall back to using standard i/o routines. You can adjust the memory limit by setting **RCS\_MEM\_LIMIT** to a numeric value *lim* (measured in kilobytes). An empty value is silently ignored. As a side effect, specifying **RCS\_MEM\_LIMIT** inhibits fall-back to slower routines. - **TMPDIR** Name of the temporary directory. If not set, the environment variables **TMP** and **TEMP** are inspected instead and the first value found is taken; if none of them are set, a host-dependent default is used, typically **/tmp**. ## DIAGNOSTICS The RCS file name and the revisions outdated are written to the diagnostic output. The exit status is zero if and only if all operations were successful. ## IDENTIFICATION Author: Walter F. Tichy.\ Manual Page Revision: 5.10.1; Release Date: 2022-02-03.\ Copyright © 2010-2022 Thien-Thi Nguyen.\ Copyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.\ Copyright © 1982, 1988, 1989 Walter F. Tichy.\ ## SEE ALSO [**co**(1)](/co/1.md), [**ci**(1)](/ci/1.md), [**ident**(1)](/ident/1.md), [**rcsclean**(1)](/rcsclean/1.md), [**rcsdiff**(1)](/rcsdiff/1.md), [**rcsmerge**(1)](/rcsmerge/1.md), [**rlog**(1)](/rlog/1.md), [**rcsfile**(5)](/rcsfile/5.md). Walter F. Tichy, RCS--A System for Version Control, *Software--Practice & Experience* **15**, 7 (July 1985), 637-654. The full documentation for RCS is maintained as a Texinfo manual. If the [**info**(1)](/info/1.md) and RCS programs are properly installed at your site, the command - **info rcs** should give you access to the complete manual. Additionally, the RCS homepage: - **http://www.gnu.org/software/rcs/** has news and links to the latest release, development site, etc. ## BUGS A catastrophe (e.g. a system crash) can cause RCS to leave behind a semaphore file that causes later invocations of RCS to claim that the RCS file is in use. To fix this, remove the semaphore file. A semaphore file's name typically begins with **,** or ends with **\_**. The separator for revision ranges in the **-o** option used to be **-** instead of **:**, but this leads to confusion when symbolic names contain **-**. For backwards compatibility **rcs -o** still supports the old **-** separator, but it warns about this obsolete use. Symbolic names need not refer to existing revisions or branches. For example, the **-o** option does not remove symbolic names for the outdated revisions; you must use **-n** to remove the names.\