perl -pe 'next if /^(\s*)#/' file.conf > clean-file.conf"

##</code><code>##

perl -e "for(glob '*.xls'){$o=$_; s/(\.xls)$/.old$1/i;rename $o,$_}"

##</code><code>##

perl -e "for(glob '*'){next unless -f;@s=stat;unlink($_) if (time-$s[9])>60*60*48;}"

##</code><code>##

perl -MFile::Find -e "find(sub{@s=stat;unlink if (time-$s[9])>60*60*48 && -f},'.')";