Splits or dissects large patch file into smaller per-file-change patches. Comes in handy when patches don't apply anymore.

split-patch.pl

#!/bin/perl

while (<>) {
    if(/^diff --git a\/(\S+)/) {
        close $f if $f;
        $s=$1;
        $s =~ s:(/|\.):_:g;
        $n=sprintf("%03d_%s.patch", ++$i, $s);
        open $f, ">", $n;
        print $f $_;
        next;
    }
    print $f $_ if $f;
}