Checking status of program

This always works if I just type:if [ ! "$(pgrep 开发者_运维百科vlc)" ]; then echo not running; else echo running; fi in the command prompt, but as soon as I make it a script, give it chmod +x and run it I always get "running" as the output. Can someone give me a lead?

#!/bin/bash
export DISPLAY=:0


if [ ! "$(pgrep vlc)" ]; then echo not running; else echo running; fi

If the name of your script contains 'vlc', pgrep founds that script running and condition in if is false, even though real VLC is not running.

You could insert

   echo "$(pgrep vlc)"

before the if stament

You can be more selective with your pgrep command. It's not necessary to use command substitution and brackets.

#!/bin/bash
export DISPLAY=:0

if ! pgrep -f "/path/to/vlc " >/dev/null; then echo not running; else echo running; fi

another option to avoid mixup with your own script is to use ps's '-C' flag (I dont know how portable it is though)

if ps -C vlc > /dev/null ; then echo running; else echo not runing; fi