CODEWITHSUNDEEP
bashshellunix
Telefang
Telefang

Reputation: 133

Check if a process is running with shell script

I'm trying to make a script to see if the process chromium is running. The script should check every 10 seconds if the process is running and it must end when it finds it 10 times. Here is my code.

#!/bin/bash

count=0

while true; do
    sleep 10s
    isthere=`$(top) | grep -w chromium`
    if [ $isthere -ne 0 ]; then
        count=$((count+1))
    fi
    if [ $count -eq 10 ]; then
        echo "You found the process 10 times"
        exit 50
    fi
done

I'm having no output whatsoever. I don't know if I'm using the command top properly.

Upvotes: 0

Views: 2273

Answers (2)

Kusalananda
Kusalananda

Reputation: 15613

Please use pgrep.

$ if pgrep ksh >/dev/null; then echo "ksh is running"; fi
ksh is running

In a loop:

i=0
while (( i < 10 )); do
  if pgrep ksh >/dev/null; then
    (( ++i ))
  fi
  sleep 10
done

Substitute ksh with the tool of your choice.

Upvotes: 0

Edgar Rokjān
Edgar Rokjān

Reputation: 17483

Yep, your usage of top command is incorrect. You try to invoke it from the shell script and it hangs as a result.

You should use top command with some specific options. I suggest you use it with -b option which corresponds to the "batch" mode and -n options which is for the number of iterations top produces its output. For more information check man top.

Also the test for isthere variable should be amended (we check it for non-emptyness).

The resulting script which works is something like this:

#!/bin/bash

count=0

while true; do
    sleep 10s
    isthere=`top -b -n 1 | grep -w chromium`
    if [ -n $isthere ]; then
        count=$((count+1))
    fi
    if [ $count -eq 10 ]; then
        echo "You found the process 10 times"
        exit 50
    fi
done

Upvotes: 1

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