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
"-basepath"
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).