Script for setting up multiple terminals.

16.09.2016 19:04

Sometimes I'm working on software that requires running a lot of different inter-dependent processes (are microservices still a thing?). Using systemd or some other init system for starting up such systems is fine for production. While debugging something on my laptop however it's useful to have each process running in its own X terminal. This allows me to inspect any debug output and to occasionally restart something. I used to have scripts that would run commands in individual GNU screen sessions, but that had a number of annoying problems.

I've recently came up with the following:

#!/bin/bash

set -ue

if [ "$#" -ne 1 ]; then
	echo "USAGE: $0 path_to_file"
	echo "File contains one command per line to be started in a terminal window."
	exit 1
fi

cat "$1" | while read CMD; do
	if [ -z "$CMD" -o "${CMD:0:1}" = "#" ]; then
		continue
	fi

	RCFILE=`tempfile`

	cat > "$RCFILE" <<END
source ~/.bashrc
history -s $CMD
echo $CMD
$CMD
END

	gnome-terminal -e "/bin/bash --rcfile \"$RCFILE\""
	rm "$RCFILE"
done

This script reads a file that contains one command per line. Empty lines and lines starting with a hash sign are ignored. For each line it opens a new gnome-terminal (adjust as needed - most terminal emulators support the -e argument) and runs the command in a way that:

  • The terminal doesn't immediately close after the command exits. Instead it drops back to bash. This allows you to inspect any output that got printed right before the process died.
  • The command is printed on top of the terminal before the command runs. This allows you to identify the terminal running a particular process in case that is not obvious from the command output. For some reason, gnome-terminal's --title doesn't work.
  • The command is appended on top of bash' history list. This allows you to easily restart the process that died (or you killed with Ctrl-C) by simply pressing the up cursor and enter keys.
Posted by Tomaž | Categories: Code

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