1: #!/bin/sh
    2: # Like mv $1 $2, but if the files are the same, just delete $1.
    3: # Status is zero if successful, nonzero otherwise.
    4: 
    5: usage="$0: usage: $0 SOURCE DEST"
    6: 
    7: case $# in
    8: 2) ;;
    9: *) echo "$usage" >&2; exit 1;;
   10: esac
   11: 
   12: for arg in "$1" "$2"; do
   13:   case $arg in
   14:    -*) echo "$usage" >&2; exit 1;;
   15:   esac
   16: done
   17: 
   18: if test -r "$2" && cmp -s "$1" "$2"; then
   19:   rm -f "$1"
   20: else
   21:   mv -f "$1" "$2"
   22: fi