**** vdb_repo_diff.pl 1.0 -- compare a vdb file against the repository ****
                            Goetz Pfeiffer 2009

graphical compare of vdb files with or within a repository

Syntax:
  vdb_repo_diff.pl {options} [file]

  generic options:
    -h: help
    --summary: give a summary of the script
    -t --textmode : show differences as text

  selection of version control system:
    --cvs: use cvs
    --svn: use subversion 
    --hg: use mercurial 
    --darcs: use darcs 

  specification of revisions (or "match/patch" with darcs):

    if no revisions are specified, compare the working copy
    with the trunk (top version in the repository)

    If a single revision is specified, compare the working copy
    with that version of the repository:

    -r [revision]

    or with darcs:
    -r [patch-string]
    --patch [patch-string]
    --match [match-string]

    If two revisions are specified, compare these two 
    revisions of the repository:

    -r [revision1] -r [revision2]

    or with darcs:
    -r [patch-string] -r [patch-string2]
    --patch [patch-string] --patch [patch-string2]
    --match [match-string] --match [match-string2]