NAME

       vdiff - display line-by-line differences between versions of files

SYNOPSIS

       vdiff [ diff-options ] [ -base path ] [ -P ] files ..

DESCRIPTION

       vdiff is a differential comparator for file versions that are stored in shapeTools' object
       base, AtFS. The functionality of vdiff is very similar to the diff command on  your  host.
       All options and switches that are recognized by diff can also be specified for vdiff.

       The  arguments to vdiff can either be a single filename, or a pair of version identifiers.
       If only a filename is specified, vdiff prints the differences between the  specified  file
       and  the  most  recent version of this file that is stored in the AtFS object base. A file
       can be compared to any stored version by specifying the version as first, and the filename
       as  second  argument.  If  both  arguments are version identifiers, the difference between
       these two versions is printed.

       Differences between files and versions can be printed in any style that  is  supported  by
       the local diff program.

       Version  identifiers  consist  of  the  filename, and a version number or alias name for a
       version, enclosed in brackets. Example:
                             retrieve.c[4.22]    or    retrieve.c[Rel-4.1]

       vdiff creates temporary copies of the versions that shall be compared,  invokes  the  diff
       command, and finally removes the temporary copies.

OPTIONS

       -base path
              If  vdiff  is told to produce a context diff, the filenames of the compared objects
              are mangeled so that the specified path replaces the path of the current  directory
              in  the  full  pathnames appearing in the diff-header. This is useful to replace an
              absolute pathname by a relative pathname and makes the produced context-diff easier
              to digest for the patch program.

       -P     With  the  -P  switch turned on, vdiff won't give up if one of the two objects that
              shall be compared does not exist. In this case an empty object is  substituted  for
              the  missing  one,  causing  the  diff  to be the complete contents of the existing
              object. This is useful in situations when complex patches are produced that upgrade
              one  release of a software system to a new release, and the system has structurally
              changed (i.e. new files have been added to the system).

SEE ALSO

       diff(1), vcat(1)

AUTHOR

       Axel.Mahler@cs.tu-berlin.de