scripts/moveifchanged

   1 #!/bin/sh
   2 #
   3 # $0 new old
   4 #
   5 # Replaces old with new if they differ. old is saved as old.bak
   6 #
   7
   8 if cmp -s "$1" "$2"; then
   9     echo "$2 is unchanged"
  10     rm "$1"
  11 else
  12     echo "Replacing $2 by $1"
  13     if [ -f "$2" ]; then
  14         mv "$2" "$2.bak"
  15     fi
  16     mv "$1" "$2"
  17 fi