Simple bash script to optimize images with guetzli

optimize_dir

#!/bin/bash

################################################
#                                              #
#  Don't forget to make this file executable   #
#  (chmod +x optimize_dir)                     #
#                                              #
#  Improvements are always welcomed  and       #
#  encouraged                                  #
#  Added a "sizes" parameter to only get image #
#  dimensions                                  #
################################################

# get passed directory
dirName=$1
cmd=$2

# if it's not a valid directory, print message and exit
if [[ ! -d $dirName ]]; then
    echo "$dirName is not valid directory"
    exit 1
fi
# count the valid files in the passed path
files=`find $dirName -name "*.jpg" -type f | wc -l`
# if no files are found, print message then exit
if  test "$files" == "0"
then
	echo "No files found in $dirName"
	exit 1
fi
# show the number of valid files found
printf "Files found: %d\n" "$files"
# processing start time
start=$(date -u -d "$(date +%H:%M:%S.%N)" +"%s.%N")

if [ -n "$cmd" ] && [ "$cmd" == "sizes" ]; then
	echo "Showing image sizes"
	# get size info about the images in the passed directory
	find $dirName -name "*.jpg" -type f -exec identify -format "%w x %h" {} \; 
else
	echo "Converting images. Please wait..."
	# recursively optimize images
	find $dirName -name "*.jpg" -type f -exec guetzli {} {} \;
fi
# processing end time
end=$(date -u -d "$(date +%H:%M:%S.%N)" +"%s.%N")
# processing end time in human readable format
elapsed=`date -u -d "0 $end sec - $start sec" +'%H:%M:%S.%N'`
# print time report
echo "Time elapsed: $elapsed"
exit 0