C.10 Expansions in administrative files

Sometimes in writing an administrative file, you might want the file to be able to know various things based on environment CVS is running in. There are several mechanisms to do that.

To find the home directory of the user running CVS (from the HOME environment variable), use ‘~’ followed by ‘/’ or the end of the line. Likewise for the home directory of user, use ‘~user’. These variables are expanded on the server machine, and don’t get any reasonable expansion if pserver (see Password authenticated) is in use; therefore user variables (see below) may be a better choice to customize behavior based on the user running CVS.

One may want to know about various pieces of information internal to CVS. A CVS internal variable has the syntax ${variable}, where variable starts with a letter and consists of alphanumeric characters and ‘_’. If the character following variable is a non-alphanumeric character other than ‘_’, the ‘{’ and ‘}’ can be omitted. The CVS internal variables are:

CVSROOT

This is the absolute path to the current CVS root directory. See Repository, for a description of the various ways to specify this, but note that the internal variable contains just the directory and not any of the access method information.

RCSBIN

In CVS 1.9.18 and older, this specified the directory where CVS was looking for RCS programs. Because CVS no longer runs RCS programs, specifying this internal variable is now an error.

CVSEDITOR

EDITOR

VISUAL

These all expand to the same value, which is the editor that CVS is using. See Global options, for how to specify this.

USER

Username of the user running CVS (on the CVS server machine). When using pserver, this is the user specified in the repository specification which need not be the same as the username the server is running as (see Password authentication server). Do not confuse this with the environment variable of the same name.

If you want to pass a value to the administrative files which the user who is running CVS can specify, use a user variable. To expand a user variable, the administrative file contains ${=variable}. To set a user variable, specify the global option ‘-s’ to CVS, with argument variable=value. It may be particularly useful to specify this option via .cvsrc (see ~/.cvsrc).

For example, if you want the administrative file to refer to a test directory you might create a user variable TESTDIR. Then if CVS is invoked as

cvs -s TESTDIR=/work/local/tests

and the administrative file contains sh ${=TESTDIR}/runtests, then that string is expanded to sh /work/local/tests/runtests.

All other strings containing ‘$’ are reserved; there is no way to quote a ‘$’ character so that ‘$’ represents itself.

Environment variables passed to administrative files are:

CVS_USER

The CVS-specific username provided by the user, if it can be provided (currently just for the pserver access method), and to the empty string otherwise. (CVS_USER and USER may differ when $CVSROOT/CVSROOT/passwd is used to map CVS usernames to system usernames.)

LOGNAME

The username of the system user.

USER

Same as LOGNAME. Do not confuse this with the internal variable of the same name.