Simple sips script to convert multiple files in directories. This is just a script that I use in regards to uploading images to e.g forums or facebook. Only works on MAC (SIPS).

smallify.sh

#!/bin/bash

# Simple script that performs SIPS-operations on mac. This script is created to simplify the actions in regards to sips, and also so that one dont have to
# remember what to do each time regarding the command I always tend to forget..duh..
# ENjoi!
#
# @version 0.1b
# @author vegaasen
# @since 16.11.2013

default_quality="normal";
default_out="/tmp/smallified";

location=$1;
size=$2;
pattern=$3;
quality=$4;
outLocation=$5;
flip=$6;

state=1;
log_level="info";

function log() {
	log=$1;
	if [ -z "$log" ]; then
		echo "-";
	fi
	if [ $log_level = "debug" ]; then
		log="[DEBUG][`date`] $log";
	else
		log="[INFO] $log";
	fi
	echo $log;
}

function printDecition() {
	echo "Do you want to continue? [y,n]";
	read cont;
	if [ -z "$cont" ]; then
		echo "[y,n]";
		read cont;
	fi
	if [ -z "$cont" ]; then
		cont="n";
	fi
	if [ $cont = "y" ]; then
		return;
	else
		log "Cancelled.";
		exit -2;
	fi
}

function assertRequiredAttributes() {
	if [ -z "$location" ] || [ -z "$size" ] || [ -z "$pattern" ]; then
		log "Required attributes (location, size, pattern) cannot be undefined.";
		state=0;
	fi
	if [ -z "$quality" ]; then
		log "Quality uses default value. Set to $default_quality.";
		quality=$default_quality;
	fi
	if [ -z "$outLocation" ]; then
		log "Save-location not set - using default value. Set to $default_out.";
		outLocation=$default_out;
	fi
	if [ ! -d "$outLocation" ]; then
		log "The defined outputlocation does not exists or is not a directory. Creating it now.";
		printDecition;
		mkdir $outLocation;
	fi
	if [ ! -w "$outLocation" ]; then
		log "Missing write-rights. Will try to add missing permissions.";
		printDecition;
		chmod u+rw $outLocation;
	fi
	if [ ! ${outLocation:${#outLocation} - 1} = "/"  ]; then
		outLocation="$outLocation/";
		log "Formatted outLocation ($outLocation).";
	fi
	if [ ! ${location:${#location} - 1} = "/" ]; then
		location="$location/";
		log "Formatted location ($location)";
	fi
}

function printUsage() {
	log "Usage: smallify.sh <location> <size> <pattern> <(opt)outLocation> <(opt)qualit[low,normal,high,best]> <(opt)flip[vertical,horizontal]>";
	log "Example: ./smallify.sh /Users/vegardaasen/develop/github/vegaasen_com/vegaasen_com_version5/resources/img/interrests/ 400 *.jpg";
}

function sipsify() {
	command="sips -Z $size --setProperty formatOptions \"$quality\"";
	if [ ! -z "$flip" ]; then
		command="$command --flip $flip";
	fi
	command="$command $location$pattern --out $outLocation";
	log "Executing command {$command}";
	$command;
}

function doTheMagic() {
	assertRequiredAttributes;
	if [ $state = 0 ]; then
		log "Mandatory attributes were not set. Cancelled.";
		printUsage;
		exit -1;
	else
		log "Using the following attributes:";
		log "Location: $location";
		log "Pattern: $pattern";
		log "Downsize-to: $size";
		log "Quality: $quality";
		log "Flip/Rotate: $flip";
	fi
	printDecition;
	sipsify;
	log "Sipsify have now completed the conversion.";
	open $outLocation; 
}

log "Initializating.";
doTheMagic;
log "Completed.";