ptardiff(1)

    ptardiff is a small program that diffs an extracted archive
    against an unextracted one, using the perl module Archive::Tar.
    This effectively lets you view changes made to an archives contents.
    Provide the progam with an ARCHIVE_FILE and it will look up all
    the files with in the archive, scan the current working directory
    for a file with the name and diff it against the contents of the
    archive.

    ptardiff ARCHIVE_FILE
    ptardiff -h
    $ tar -xzf Acme-Buffy-1.3.tar.gz
    $ vi Acme-Buffy-1.3/README
    [...]
    $ ptardiff Acme-Buffy-1.3.tar.gz > README.patch

    h   Prints this help message