Resize all image files in particular directory and put them in separate directory

resize-photo.sh

#!/bin/sh

while [ "$#" -gt 0 ]; do
  case "$1" in
    -w) width="$2"; shift 2;;
    -h) height="$2"; shift 2;;
    -p) filepath="$2"; shift 2;;
    -m) mask="$2"; shift 2;;

    --width=*) width="${1#*=}"; shift 1;;
    --height=*) height="${1#*=}"; shift 1;;
    --filepath=*) filepath="${1#*=}"; shift 1;;
    --mask=*) mask="${1#*=}"; shift 1;;
    --width|--height|--filepath|--mask) echo "$1 requires an argument" >&2; exit 1;;

    -*) echo "unknown option: $1" >&2; exit 1;;
    *) handle_argument "$1"; shift 1;;
  esac
done

if [ "$filepath" = "" ]; then
  echo "no --filepath option"
  exit 2;
fi

if [ "$width" = "" ]; then
  echo "no --width option"
  exit 2;
fi

if [ "$height" = "" ]; then
  echo "no --height option"
  exit 2;
fi

cd "$filepath" || exit
files=$(ls *$mask*)
x="x"
newdir="$width$x$height"
echo "$newdir"
mkdir "$newdir"
echo $(ls)

processing() {
  ident=$(gm identify "$1")
  size=$(echo "$ident" | sed 's/.*\([0-9]\{4\}\)x\([0-9]\{4\}\).*/\1-\2/')
  side_diff=$(($size))
  if [ $side_diff \> 0 ]; then
    echo "processing $1 (landscape)"
    gm convert -gravity center -quality 100 -resize "$width$x$height^" -crop "$width$x$height+0+0" "$1" "$newdir/$newdir---$1"
  else
    echo "processing $1 (portrait)"
    gm convert -gravity center -quality 100 -resize "$height$x$width^" -crop "$height$x$width+0+0" "$1" "$newdir/$newdir---$1"
  fi
}

# TODO: make progress bar

cores=4
trap "exit" INT
for f in $files;do
  processing $f &
  background=( $(jobs -p) )
  echo ${#background[@]}
  if (( ${#background[@]} \>= cores )); then
    wait
  fi
done