运行一次

try_to_run_once.sh

#!/bin/bash
# check daemon
check(){
	cmd=$1
	lines=`ps -ef | grep $cmd |grep -v grep |wc -l`
	# if not found - equals to 1, start it
    echo $lines
	if [ $? -eq 0 ]; then
	$cmd
	else
	echo "eq 0 - daemon found - do nothing"	
	fi
}
help(){
	echo "" $0 " YOUR_COMMAND "
}
the_cmd="testing.php"
if [ -z $the_cmd ]; then
	help
else
	check $the_cmd
fi