I wanna be a programmer .... this is my first try :)

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#!/bin/sh # bestcompress - given a file, try compressing it with all the available # compression tools and keep the compressed file that's smallest, reporting # the result to the user. If '-a' isn't specified, it skips compressed # files in the input stream. Z="compress" gz="gzip" bz="bzip2" Zout="/tmp/bestcompress.$$.Z" gzout="/tmp/bestcompress.$$.gz" bzout="/tmp/bestcompress.$$.bz" skipcompressed=1 if [ "$1" = "-a" ] ; then skipcompressed=0 ; shift fi if [ $# -eq 0 ]; then echo "Usage: $0 [-a] file or files to optimally compress" &2; exit 1 fi trap "/bin/rm -f $Zout $gzout $bzout" EXIT for name do if [ ! -f "$name" ] ; then echo "$0: file $name not found. Skipped." &2 continue fi if [ "$(echo $name | egrep '(\.Z$|\.gz$|\.bz2$)')" != "" ] ; then if [ $skipcompressed -eq 1 ] ; then echo "Skipped file ${name}: it's already compressed." continue else echo "Warning: Trying to double-compress $name" fi fi $Z $Zout & $gz $gzout & $bz $bzout & wait # run compressions in parallel for speed. Wait until all are done smallest="$(ls -l "$name" $Zout $gzout $bzout | \ awk '{print $5"="NR}' | sort -n | cut -d= -f2 | head -1)" case "$smallest" in 1 ) echo "No space savings by compressing $name. Left as-is." ;; 2 ) echo Best compression is with compress. File renamed ${name}.Z mv $Zout "${name}.Z" ; rm -f "$name" ;; 3 ) echo Best compression is with gzip. File renamed ${name}.gz mv $gzout "${name}.gz" ; rm -f "$name" ;; 4 ) echo Best compression is with bzip2. File renamed ${name}.bz2 mv $bzout "${name}.bz2" ; rm -f "$name" esac done exit 0 smallest="$(ls -l "$name" $Zout $gzout $bzout | \ awk '{print $5"="NR}' | sort -n | cut -d= -f2 | head -1)" $Z $Zout & $gz $gzout & $bz $bzout & wait