https://invisible-island.net/ded/cm_tools/

checkout(man)

NAME

       checkout - RCS check-out utility

SYNOPSIS

       checkout [options] [file-specifications]

DESCRIPTION

       Checkout  is  an  extension  of  the  RCS utility co.  It uses a file's
       check-in date to set the file's modification date after check-out.

       Checkout uses the rcs utility co.  It  is  normally  invoked  from  the
       rcsget  script,  but  may  be invoked in a standalone manner.  Checkout
       differs from co primarily in its treatment to  the  delta  date:  after
       invoking  co,  checkout  sets the file's modification date to match the
       delta-date for the extracted version.

Set-UID Operation

       Like the checkin utility, checkout properly handles  set-uid  operation
       for  a  non-root  effective  user.  The archived files are owned by the
       effective user, and the checked-out files are owned by the real user.

       Note that since checkin initializes the  access  list  in  the  archive
       files, the real user must appear on the access list to lock a file.  Of
       course,  if  no  lock  is made, then the user need not be on the access
       list.

OPTIONS

       Checkout recognizes all of the "co" options except for the "-d"  cutoff
       date.  Instead, the "-c" option is used:

       -c cutoff
           specifies the rcs cutoff date, in SCCS-format

                YY[MM[DD[HH[MM[SS]]]]]

           Punctuation in the date is permitted.  For example,

                -c 77/2/2 9:22:25
                -c 770202092225

           represent  the same date.  This option is translated to the co "-d"
           option.

       Use the "-x" option of checkout to direct it  to  retain  the  pathname
       when  translating  between  working and archive files, e.g, "path/name"
       becomes "path/RCS/name,v".  If the "-x" option is not set,  "path/name"
       becomes "./RCS/name,v", and "path/RCS/name,v" becomes "./name".

OPERATIONS

       To  extract  files  using  checkout,  you must provide one or more file
       names.  For each name, checkout parses the leaf-name and  extracts  the
       specified version from the "./RCS" directory.

ENVIRONMENT

       Checkout is a C-language program.  It invokes co via an execlp call (so
       that  co must be in your path), and performs pre- and postprocessing of
       the archive and working file to determine the delta-date to use for the
       extracted file.  Environment variables used by checkout include:

       RCS_DIR
              if defined, specifies the directory in which rcs
               archive files are found.  Normally files are found in "./RCS".

       TZ     is the POSIX time zone, which is overridden internally  so  that
              file modification dates are independent of the local time zone.

FILES

       Checkout uses the following files:

       co     the RCS check-out program

ANTICIPATED CHANGES

       This does not handle rcs branches properly.

       Checkout does not handle the "-j" and "-p" options of co.

AUTHORS

       Thomas E. Dickey <dickey@invisible-island.net>