#!/bin/bash
#                      /usr/local/bin/rename.sh
# http://crystalfaeries.net/posix/bin/rename.sh
# not originally by, but adopted by:
# celeste:crystalfaery 2015-04-19 08:38:38+00:00
# Original author and license unknown... Please
# notify kahealani@inbox.com if you know its source!

# Usage:
# rename PATTERN NEWNAME
#
# e.g.:
# rename IMG_11 iphone-screen-pic-

renumber=0; fixpng=1; doit=1; count=1

args=$(getopt npt $*)

if [ $? != 0 -o $# -lt 2 ] ; then
  echo "Usage: $(basename $0) {-p} {-n} {-t} PATTERN NEWPATTERN"
  echo "
  echo " -p  rewrites PNG to png"
  echo " -n  sequentially numbers matching files with"
  echo "     NEWPATTERN as base filename"
  echo " -t  test mode: show what you’ll do, don’t do it."
  exit 0
fi
set -- $args

for i; do
  case "$i"
  in
   -n ) renumber=1 ; shift ;;
   -p ) fixpng=1   ; shift ;;
   -t ) doit=0     ; shift ;;
   -- ) shift; break ;;
fi

matches="$(ls -1 $1* 2>&1 | grep -v "No such file" | wc -l)"

if [ $doit -eq 0 ] ; then
  echo "Debug: renumber = $renumber, fixpng = $fixpng, doit = $doit, matches = $matches"
fi

if [ $matches -eq 0 ] ; then
  echo "Error: no files match pattern $1*"
  exit 0
fi

for name in $1*
do
  new="$(echo $name | sed "s/$1/$2/")"

  if [ $fixpng -eq 1 ] ; then
    new="$(echo $new | sed 's/PNG$/png/')"
  fi

  if [ $renumber -eq 1 ] ; then	   # with renumbering, we discard original filename
    # the following assumes that we only have a single dot in the filename !!
    suffix="$(echo $name | cut -d. -f2- | tr '[A-Z]' '[a-z]')"
    new="$2$count.$suffix"
    count=$(( $count + 1 ))
    echo "mv $name $new"
    if [ $doit -eq 1 ] ; then 
      mv $name $new ; chmod a+r $new
    fi
  else
    echo "mv $name $new"
    if [ $doit -eq 1 ] ; then
      mv $name $new ; chmod a+r $new
    fi
  fi
done

exit 0