: mv-if-diff file1 file2 : move file1 to file2 if file1 and file2 are different. if test $# -lt 2 ; then echo "usage: $0 file1 file2" echo "move file1 to file2 if file1 and file2 are different." exit 1 fi if cmp $1 $2 >/dev/null 2>&1; then echo "File $2 not changed." rm -f $1 else rm -f $2 mv $1 $2 fi