Allow watching files from bash using the default lessc

c_LESS.sh

## compile less files from bash (shell)
## v 0.0.1-SNAPSHOT
#########################################################
## This script will compile ONE less-file to ONE css-file
## allow to compile "once" or "watch"
#########################################################
## DEPENDENCIES:
## observr         https://github.com/kevinburke/observr
## lessc           https://github.com/less/less.js/
#########################################################
## $ (sudo) gem install observr
## $ npm install (-g) less



#########################################################
################### START CONFIG ########################
#########################################################
## set files and path
## modify these to fit your needs

lessPath="less"
cssPath="css"
inputFile="input.less"
outputFile="output.css"

#########################################################
#################### END CONFIG #########################
#########################################################


#########################################################
## NO MODIFICATIONS SHOULD BE NEEDED BEYOND THIS POINT ##
#########################################################

#########################################################
################### START SCRIPT ########################
#########################################################

## build filePath + fileName
INPUT="${lessPath}/${inputFile}"
OUTPUT="${cssPath}/${outputFile}"

## flag to check if command was sucessfully executed
COMPLETED="NO"

LINEBREAK="--------------------------------------------------------------------------------"
## define PARAMETER
PARAMETER=""

if [ -n "${2}" ] ; then
	if [ ${2} = "-m" ] || [ ${2} = "-mediaquery" ] ; then
		PARAMETER="--line-numbers=mediaquery"
	elif [ ${2} = "-c" ] || [ ${2} = "-comments" ] ; then
		PARAMETER="--line-numbers=comments"
	elif [ ${2} = "-a" ] || [ ${2} = "-all" ] ; then
		PARAMETER="--line-numbers=all"
	fi
fi

## will compile files with given parameters
function compile-less () {
	echo "start compiling less files"
	echo "${LINEBREAK}"
	lessc ${PARAMETER} ${INPUT} ${OUTPUT} && COMPLETED="YES"
	if [ ${COMPLETED} = "YES" ] ; then
		echo "${INPUT} > ${OUTPUT}"
		echo "${LINEBREAK}"
	else
		echo "seems like something went wrong"
	fi
}
## will compile files with given parameters
## and then watch for changes
function watch-less () {
	## fist compile the files
	compile-less
	## use observr to watch files
	observr -e "; \
	puts 'start watching less files'; \
	puts '-' * 80; \
	watch('.*\.less') \
	{ cmd = 'lessc ${PARAMETER} ${INPUT} ${OUTPUT}'; \
	log = 'echo \"${INPUT} > ${OUTPUT}\"'; \
	o = \`#{cmd}\`; \
	l = \`#{log}\`; \
	puts o << l;}"
}

## provide error message
function illegal-option (){
	echo "illegal option"
	echo "use '--help' to show options"
}

## output help when requested
function show-help () {
	echo -e "c_LESS.sh [OPTION] <PARAMETER>"
	echo -e ""
	echo -e "OPTION---------------------HELP------------------------------"
	echo -e "watch                      watch files"
	echo -e "once                       compile files once"
	echo -e ""
	echo -e "PARAMETER------------------HELP------------------------------"
	echo -e "-c, --comments             output comments"
	echo -e "-m, --mediaquery           output mediaquery"
	echo -e "-a, --all                  output comments & mediaquery"
	echo -e ""
	echo -e "-------------------------------------------------------------"
	echo -e "-h, --help                 show this info"
	echo -e "-------------------------------------------------------------"
}

## keep this small and modular ##
#################################
## only execute if option is set
if [ -n "${1}" ] ; then
	echo ""
	if [ ${1} = "-h" ] || [ ${1} = "--help" ] ; then
		show-help
	elif [ ${1} = "watch" ] ; then
		watch-less
	elif [ ${1} = "once" ] ; then
		compile-less
	else
		illegal-option
	fi
## otherwise display help
else
	show-help
fi


#########################################################
#################### END SCRIPT #########################
#########################################################