Resize all JPEG files in current directory, to <GEOMETRY> size

resize_jpegs.sh

#!/bin/bash
function shw_grey { echo -e '\033[1;30m'"$1"'\033[0m'; }
function shw_norm { echo "$1"; }
function shw_info { echo -e '\033[1;34m'"$1"'\033[0m'; }
function shw_warn { echo -e '\033[1;33m'"$1"'\033[0m'; }
function shw_err { echo -e '\033[1;31mERROR: '"$1"'\033[0m'; }

function shw_usage {
  cat <<EOT
Resize all JPEG files in current directory, to <GEOMETRY> size
(Needs ImageMagick installed, for 'convert')

Usage:    $0 [<GEOMETRY>]
                  where <GEOMETRY> is described in http://www.imagemagick.org/script/command-line-processing.php#geometry and can be one of:
                        scale%              Height and width both scaled by specified percentage.
                        scale-x%xscale-y%   Height and width individually scaled by specified percentages. (Only one % symbol needed.)
                        width               Width given, height automagically selected to preserve aspect ratio.
                        xheight             Height given, width automagically selected to preserve aspect ratio.
                        widthxheight        Maximum values of height and width given, aspect ratio preserved.
                        widthxheight^       Minimum values of width and height given, aspect ratio preserved.
                        widthxheight!       Width and height emphatically given, original aspect ratio ignored.
                        widthxheight>       Shrinks an image with dimension(s) larger than the corresponding width and/or height argument(s).
                        widthxheight<       Enlarges an image with dimension(s) smaller than the corresponding width and/or height argument(s).
                        area@               Resize image to have specified area in pixels. Aspect ratio is preserved.
                  <GEOMETRY> defaults to "2000x2000" (max width 2000 or max height 2000, aspect ratio preserved)

Examples:
  $0 50%
  $0 2000x2000


EOT
}

shw_usage

# $0 -h|--help
[[ "$1" =~ -h ]] && exit 255

#set GEOMETRY
if [[ $1 ]]; then
  GEOMETRY=$1
else
  GEOMETRY="2000x2000"
fi

#Are you sure
shw_warn "This will resize all fotos in current dir to '$GEOMETRY'"
shw_warn "Are you sure ? yes/[no]"
read ANSWER
[[ "$ANSWER" != "yes" ]] && exit 254

TMP_DIR=$(mktemp -d)
OLD_IFS=$IFS
IFS=$'\n'
for FILE in $(ls -1 . | egrep -i '\.(jpg|jpeg)$'); do
   TMP_FILE=$TMP_DIR/$(basename $FILE)
   shw_info ".....resizing $FILE"
   convert "$FILE" -resize "$GEOMETRY" "$TMP_FILE" && mv -f "$TMP_FILE" "$FILE"
done
IFS=$OLD_IFS
rm -rf $TMP_DIR
shw_info "Finished"