SalvageLog pruning Perl script

[Joseph_Jackson]

#!/usr/bin/perl

# SalvageLog.prune <filename>

# Written by John Myers of Carnegie Mellon University ([EMAIL PROTECTED])
# Minor updates for AFS 3.2 by Joseph Jackson of Transarc, Corp.
#   ([EMAIL PROTECTED])

# This Perl script processes salvager log files, removing all the
# "uninteresting" lines from it.  Sections that have been elided are
# replaced by ellipsis (...).  Provide the name of the log file as an
# argument to the script.

# Groups of lines are deemed "uninteresting" if they appear similar to the
# results of a successful volume salvage, that is, if they have the form:

#    CHECKING CLONED VOLUME 536873867.
#    user.jackson.backup (536873867) updated 10/27/92 15:25
#    SALVAGING VOLUME 536873865.
#    user.jackson (536873865) updated 11/03/92 14:34
#    Salvaged user.jackson (536873865): 63 files, 864 blocks

# Any non-conforming or extra lines are presumed to be errors, causing the
# unusual line to be printed along with the surrounding block of lines.

$history = '';

while (<>) {
        if (/CHECKING CLONED VOLUME (\d+)\.$/) {
                $oldhistory = '';
                $history .= $_;
                $vid = $1;
                $_ = <ARGV>;
                if (/(\S+)\.(backup|readonly) \($vid\) updated / &&
                    (!$volname || $volname == $1)) {
                        $history .= $_;
                        $volname = $1;
                }
                else {
                        print $history;
                        print $_;
                        $history = $volname = '';
                }
        }
        elsif (/SALVAGING VOLUME (\d+)\.$/) {
                $oldhistory = '';
                $history .= $_;
                $vid = $1;
                $_ = <ARGV>;
                if (/(\S+) \($vid\) updated / &&
                    (!$volname || $volname == $1)) {
                        $history .= $_;
                        $volname = $1;
                }
                else {
                        print $history;
                        print $_;
                        $history = $volname = '';
                }

        }
        elsif (/Salvaged $volname \($vid\): /) {
                $oldhistory = $history . $_;
                $volname = '';
                $history = "...\n";
        }
        elsif (/SALVAGING OF PARTITION \/vicep[a-z] COMPLETED$/) {
                print $history;
                print $_;
                $history = $volname = $vid = $oldhistory = '';
        }
        else {
                print $oldhistory ? $oldhistory : $history;
                print $_;
                $history = $volname = $vid = $oldhistory = '';
        }
}