#
# Rename files in the current directory by suffix ("ren -s .c .cpp"), 
# or by prefix ("ren -p .X xconfig-").
#

(( $# == 3 )) ||
   { print -u2 "Usage: $0 -p|-s substr1 substr2" ; return 1 }

case $1 in

   -s) for f in *$2
       do
          mv $f ${f%$2}$3
       done;;

   -p) for f in ${2}*
       do
          mv $f $3${f#$2}
       done;;

   *) print -u2 "Usage: $0 -p|-s substr1 substr2"           
      return 1;;

esac