NAME

       pristine-gz - regenerate pristine gz files

SYNOPSIS

       pristine-gz [-vdk] gendelta file.gz delta

       pristine-gz [-vdk] gengz delta file

DESCRIPTION

       This is a complement to the pristine-tar(1) command. Normally you don't need to run it by
       hand, since pristine-tar calls it as necessary to handle .tar.gz files.

       pristine-gz gendelta takes the specified gz file, and generates a small binary delta file
       that can later be used by pristine-gz gengz to recreate the original file.

       pristine-gz gengz takes the specified delta file, and compresses the specified input file
       (which must be identical to the contents of the original gz file). The resulting file will
       be identical to the original gz file used to create the delta.

       The approach used to regenerate the original gz file is to figure out how it was produced
       -- what compression level was used, whether it was built with GNU gzip(1) or with a
       library or BSD version, whether the --rsyncable option was used, etc, and to reproduce
       this build environment when regenerating the gz.

       This approach will work for about 99.5% of cases. One example of a case it cannot
       currently support is a gz file that has been produced by appending together multiple gz
       files.

       For the few where it doesn't work, a binary diff will be included in the delta between the
       closest regneratable gz file and the original. In the worst case, the diff will include
       the entire content of the original gz file, resulting in a larger than usual delta. If the
       delta is much larger than usual, pristine-gz will print a warning.

       If the delta filename is "-", pristine-gz reads or writes it to stdio.

OPTIONS

       -v
       --verbose
           Verbose mode, show each command that is run.

       -d
       --debug
           Debug mode.

       -k
       --keep
           Don't clean up the temporary directory on exit.

ENVIRONMENT

       TMPDIR
           Specifies a location to place temporary files, other than the default.

AUTHOR

       Joey Hess <joeyh@debian.org>, Faidon Liambotis <paravoid@debian.org> Josh Triplett
       <josh@joshtriplett.org>

       Licensed under the GPL, version 2.