wait_for_process

Simple utility to wait for matching running processes to finish and exit.

INTRODUCTION

If you have one or more processes running on the same machine but outside of your current tty this program provides a convenient way to wait for these other processes to finish before executing another command. For example, if we are running one or more instances of "analysis_command" that generates data we want to compress once completed, we might run something like the following:

wait_for_process -p analysis_command && tar -cjvf output.tar.bz2 /path/to/output_folder

REQUIREMENTS

This program is designed to work on Linux systems - it relies on the pgrep command and on the /proc folder. It is written in perl and should not require any additional software or modules other than that included in a most standard perl distributions bundled with your OS.

INSTALLATION

Clone this repo:

git clone https://github.com/david-a-parry/wait_for_process.git

Either run directly from the cloned repo:

./wait_for_process/wait_for_process [options]

Or add to/copy to somewhere in your PATH and invoke directly - e.g.

cp ./wait_for_process/wait_for_process $HOME/bin
wait_for_process [options]

BACKGROUND

A simple way to wait for a process to end without this script is the following:

tail --pid=${pid} -f /dev/null

Which works fine if you know the processes PID already. This program provides some convenience functions including:

• letting you specifying the process name(s) that you want to wait for
• letting you use any part of the full process name(s) that you want to wait for
• letting you continuously check for matching processes and wait for any newly spawned matching process

See the usage below for more details.

SYNOPSIS

    wait_for_process [program name]
    wait_for_process -p [program name]
    wait_for_process -f [pattern in full command line]
    wait_for_process -u [user]
    wait_for_process -i [pid]
    wait_for_process -h (display help message)
    wait_for_process -m (display manual page)

ARGUMENTS

• -p --process

  One or more programs to check processes for.

• -f --full

  One or more strings to search in full commands.

• -u --user

  One or more users to restrict search to. If used without --process or --full arguments will search all users processes (including logins!).

• -i --id

  One or more specific PIDs to check regardless of other options.

• -d --delay

  Delay in seconds between checks. Defaults to 10.

• -c --continuous

  Continuously check for new processes matching your criteria and wait for these to finish too.

• -q --quiet

  Suppress printing of matching/finished PIDs.

• -n --non_interactive

  Use this if for some reason you don't want to be able to exit the program by pressing the 'Q' key.

• -h --help

  Display help message and exit.

• -m --manual

  Show manual page and exit.

EXAMPLES

• wait_for_process -p cat

  wait for all 'cat' processes to finish

• wait_for_process cat

  as above, command line arguments are assumed to be processes if not preceded by one of the above argument categories

• wait_for_process -p cat -u bob

  wait for all 'cat' processes being run by user 'bob' to finish

• wait_for_process -u bob

  wait for all processes being run by user 'bob', including logins, to finish

• wait_for_process -f foo -c

  wait for all commands containing the word 'foo' to finish, including processes spawning while this program is running

• wait_for_process -p cat -f foo

  wait for all 'cat' processes AND all commands containing the word 'foo' to finish

• wait_for_process -p cat -f foo -u bob

  wait for all 'cat' processes by user 'bob' AND all commands containing the word 'foo' by user 'bob' to finish

• wait_for_process -i 1234

  wait for process 1234 to finish

DESCRIPTION

This program searches for running processes that match the provided arguments and waits until they have finished before exiting. It can be used to queue a command you want to run once one or more other processes in another session have finished.

e.g. wait_for_process -p [command generating big_text_file.txt] ; gzip -9 big_text_file.txt

You can exit manually at any time by pressing 'Q' (unless using the --non_interactive option).

Please note - this program only searches for processes running at the time of its execution unless using the --continuous flag.

AUTHOR

David A. Parry

COPYRIGHT AND LICENSE

Copyright 2021 David A. Parry

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.