manage script in bash

manage.sh

#!/usr/bin/env bash
# template for maange script in bash
# provide listing functions / usage.. etc

CWD="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# START vars
LOG_FILE="$CWD/log.log"
# END vars

# START functions declare
function usage {
	echo "$(basename $0), params: [$(echo $LIST_FUNCS)]"
}

function log {
    echo "`date`  $1" | tee -a $LOG_FILE
}

# define custom functions here

LIST_FUNCS=$(declare -F | cut -d ' ' -f3 | sed 's/usage\|log//')
# END functions declare

# main body
case $# in
	1)  # i just need one parmas
		if [[ -n "`echo $LIST_FUNCS | xargs -n1 echo | grep -e \"^$1$\"`" ]]; then
			echo "'$1' match"
			echo "run \`$1\`"
			type $1 
			# run, using name of function provied in CLI args
			$1
		else
			echo "'$1' not match"
			usage
		fi    
		;;
	*)
		usage
		;;
esac