GNU Screen – How to Execute a Command and Detach

You have to make the file executable. You can do that with

chmod +x <filename>

where is the name of your script and then you have to prepend it with ./ to instruct the shell to run a file in the local directory, like:

./script.sh

You can only run files that are in your PATH or that you specify a path to them. ./, the local directory, is not in the PATH by default because someone may use it for nefarious purposes. Imagine a script called ls dropped in a directory, you go inside that directory, run ls and that script does something bad.

While you are at it you may want to make it more portable by running shell instead of bash by using:

#!/bin/sh

or by running bash no matter where it is installed as long as it is installed:

#!/usr/bin/env bash

Start a named screen session (-S) with a named window (-t) adapting to the terminal size (-A) in detached mode (-d -m):

screen -S mySessionName -t myWinName0 -A -d -m

Start another named window (-t) in the same screen session (-S):

screen -S mySessionName -X screen -t myWinName2

Stuff a few commands (-X stuff $'cmds') into the first named window (-p) in the session (-S):

screen -S mySessionName -p myWinName0 -X stuff $'echo myWinName0\necho cmd1\necho cmd2\n'

Stuff a few commands (-X stuff $'cmds') into the second named window (-p) in the session (-S):

screen -S mySessionName -p myWinName1 -X stuff $'echo myWinName1\necho cmd1\necho cmd2\n'

List the screen sessions and reattach to see what happened:

screen -ls
screen -r mySessionName

Note: The linefeed (\n) simulates pressing Enter. You could use semicolons to separate commands as well.