Unix in a Nutshell, 4th Edition

Standard Options and Environment Variables

RCS defines an environment variable, RCSINIT, which sets up default options for RCS commands. If you set RCSINIT to a space-separated list of options, they will be prepended to the command-line options that you supply to any RCS command.

Six options are useful to include in RCSINIT: -q, -V, -V n, -T, -x, and -z. They can be thought of as standard options because most RCS commands accept them.

-q[ R ]

Quiet mode; don’t show diagnostic output. R specifies a file revision.

-T

If the file with the new revision has a later modification time than that of the RCS file, update the RCS file’s modification time. Otherwise, preserve the RCS file’s modification time. This option should be used with care; see the discussion in the ci manpage for more detail.

-V

Print the RCS version number.

-V n

Emulate version n of RCS; useful when trading files between systems that run different versions. n can be 3, 4, or 5.

-x suffixes

Specify an alternate list of suffixes for RCS files. Each suffix is separated by a /. On Unix systems, RCS files normally end with the characters ,v. The -x option provides a workaround for systems that don’t allow a comma character in filenames.

-z timezone

timezone controls the output format for dates in keyword substitution. timezone should have one of the following values:

Value	Effect
empty	Default format: UTC with no time zone and slashes separating the parts of the date.
LT	The local time and date, in ISO-8601 format, ...