shell脚本报错："[: =: unary operator expected"

pid=`ps -ef|grep deploy|egrep -v 'grep'|awk -F '[ ]+' '{print $3}'`
if [ $pid -ne 0 ]
then
kill $pid

fi

上面脚本执行报错"[: =: unary operator expected"
需要把[ $pid -ne 0 ] 改为"[[ $pid -ne 0 ]]"即可