convert_to_webp.sh

#!/bin/bash

isDir()  
{  
	local dirName=$1
	if [ -d $dirName ]; then  
		echo true 
	else  
		echo false 
	fi  
}

isImage()
{
	local fileName=$1
	if [[ $fileName == *png || $fileName == *jpg ]]; then
		echo true
	else
		echo false
	fi
}

isExistWebp()
{
	local fileName=$1
	fileName="${fileName}.webp"
	if [ -f $fileName ]; then
		echo true
	else
		echo false
	fi
}
	
recursionDir()  
{  
	local dir=$1  
	echo "current dir: ${dir}"
	if $(isDir "${dir}")  
	then :  
	else  
		echo "error,please pass a dirctory";  
		exit 1  
	fi  
	
	local filelist=`ls -tr "${dir}"`  

	for filename in $filelist  
	do  
		local fullpath="${dir}"/"${filename}";  
		if $(isDir "${fullpath}");then  
			recursionDir "${fullpath}"  
		else
			if $(isImage "${fullpath}") && ! $(isExistWebp "${fullpath}");then
				echo "${fullpath}.webp not exist!"
				cwebp "${fullpath}" -o "${fullpath}.webp"
			fi
		fi  
	done  
}  

#usage:	
recursionDir "./static"