Question

What I’m trying to do is to start a process if not started. Here is what I try

#!/bin/bash
pid=`ps ax | grep app | grep -v grep | wc -l`
  if [ $pid = 0 ]
then
 /etc/init.d/app start
fi

The problem is that the line

/etc/init.d/app start

is not executed. What is wrong here ?
I know that I can you daemontools but I like the “bash” approach.

Answer 1

Take a look at the == operator.

Best may be something like

pid=`ps ax | grep app | grep -v grep`
test -z "$pid" && /etc/init.d/app start