Shell：判断一个进程是否存在

#test.sh
#！/bin/sh
pid=`ps -ef | grep -v grep | grep -v "test.sh" | grep $1 | sed -n "1P" | awk "{print $2}"`
if [ -z $pid ] ; then
echo "no this process"
else
echo $pid
fi

例：查询是否存在hello进程#./test.sh hello如果存在hello进程，会输出PID不存在会输出 no this process