Shell script: monitor task launch

Question

Hi,

In a script I'd like to monitor the process list in a way that, in order to continue the execution of the script, a certain process has to be started.

I came up with something like:

while ! pgrep "process_to_match"
do
  sleep 10
done;

# the rest of the script

The problem with that script is that if the "process_to_match" is started for less than 10ms the "rest of the script" won't be executed.

An even better solution for me would be to trigger the execution of a script on "process_to_match" launch.

Any ideas? Thanks.

Answer 1

Can you check in another way that the process has been executed? I mean does this process logs or modifies anything?

If not, you can replace the process by a shell script (rename the process and create a shell with the process file name) that will log something after running the process you are waiting for.

Answer 2

What is your actual need?

If you know the PID of the process you are monitoring, then you just have to wait for it:

wait $pid

Obtaining this PID is as simple as:

process_to_match & pid=$!