Open terminal with multiple tabs and execute application which uniquely modifies PS1 variable for each tab

Question

What I'm trying to do:

1. Write a script to open 3 tabs.
2. cd into a different folder in each tab (ie: run a unique command).
3. get each tab to have a unique title by modifying its local PS1 variable
4. Ensure each tab stays open after the script is run

I want this scripted so I can click the script on my Desktop and have it open up terminals as I'd like for my daily development environment.

Description:

I have this script to try and open 3 terminal tabs with unique commands to be run in the tabs:

open_tabs.sh

#!/bin/bash

gnome-terminal --tab -- bash -ic "set-title title 1; exec bash"
gnome-terminal --tab -- bash -ic "cd ~; set-title title 2; exec bash"
gnome-terminal --tab

When I run it with ./open_tabs.sh, it opens up 3 new tabs, but unfortunately set-title doesn't work to set the tab title! It appears the PS1 variable isn't staying set with my set-title call. The exec bash is there to keep the tab open, per this answer and comments underneath it.

I have set-title defined as a function in ~/.bashrc like this. Its purpose is to set the title string at the top of any terminal window. It works perfectly when I use it manually. Ex: set-title hey how are you? will put "hey how are you?" at the top of my terminal window.

# From: https://unix.stackexchange.com/questions/177572/how-to-rename-terminal-tab-title-in-gnome-terminal/566383#566383
set-title() {
    # If the length of string stored in variable `PS1_BAK` is zero...
    # - See `man test` to know that `-z` means "the length of STRING is zero"
    if [[ -z "$PS1_BAK" ]]; then
        # Back up your current Bash Prompt String 1 (`PS1`) into a global backup variable `PS1_BAK`
        PS1_BAK=$PS1 
    fi

    # Set the title escape sequence string with this format: `\[\e]2;new title\a\]`
    # - See: https://wiki.archlinux.org/index.php/Bash/Prompt_customization#Customizing_the_terminal_window_title
    TITLE="\[\e]2;$@\a\]"
    # Now append the escaped title string to the end of your original `PS1` string (`PS1_BAK`), and set your
    # new `PS1` string to this new value
    PS1=${PS1_BAK}${TITLE}
}

How do I fix this so that each tab runs a command, sets its title by modifying its PS1 variable, and stays open?

Note that gnome-terminal has deprecated its --title and --command options, hence these work-arounds.

Related:

1. bash: "command not found" when calling function defined in ~/.bashrc file in `bash -c` command while opening gnome-terminal tab
2. https://unix.stackexchange.com/questions/177572/how-to-rename-terminal-tab-title-in-gnome-terminal/566383#566383

3. Open Terminal with multiple tabs and execute application <== this is what I'm really trying to solve, but gnome-terminal's --command (-e) option is now deprecated!

   # Option “--command” is deprecated and might be removed in a later version of gnome-terminal.
   # Use “-- ” to terminate the options and put the command line to execute after it.
   

4. How to run a script without closing the terminal?

Answer 1

As is the case with most programming, solving the problem was extremely hard. I had to study a bunch about Bash variables, and how to use export and source (or the POSIX dot operator, .), and how bash loads, and what interactive -i bash mode was, etc etc.

I found man bash and man test to also be useful. Here's how to do what I want to do, which is:

1. Write a script to open 3 tabs.
2. cd into a different folder in each tab (ie: run a unique command).
3. get each tab to have a unique title by modifying its local PS1 variable
4. Ensure each tab stays open after the script is run

1st, add this to the bottom of your ~/.bashrc file:

# Function to allow a user to arbitrarily set the terminal title to anything
# Example: `set-title this is title 1`
set-title() {
    # Set the PS1 title escape sequence; see "Customizing the terminal window title" here: 
    # https://wiki.archlinux.org/index.php/Bash/Prompt_customization#Customizing_the_terminal_window_title
    TITLE="\[\e]2;$@\a\]" 
    PS1=${PS1_BAK}${TITLE}
}

# Back up original PS1 Prompt 1 string when ~/.bashrc is first sourced upon bash opening
if [[ -z "$PS1_BAK" ]]; then # If length of this str is zero (see `man test`)
    PS1_BAK=$PS1 
fi

# Set the title to a user-specified value if and only if TITLE_DEFAULT has been previously set and
# exported by the user. This can be accomplished as follows:
#   export TITLE_DEFAULT="my title"
#   . ~/.bashrc
# Note that sourcing the ~/.bashrc file is done automatically by bash each time you open a new bash 
# terminal, so long as it is an interactive (use `bash -i` if calling bash directly) type terminal
if [[ -n "$TITLE_DEFAULT" ]]; then # If length of this is NONzero (see `man test`)
    set-title "$TITLE_DEFAULT"
fi

2nd, create this script to open 3 unique tabs with 3 unique cd commands and 3 unique titles:

open_tabs.sh:

gnome-terminal --tab -- bash -ic "export TITLE_DEFAULT='title 1'; cd ..; exec bash;"
gnome-terminal --tab -- bash -ic "export TITLE_DEFAULT='title 2'; cd ../..; exec bash;"
gnome-terminal --tab -- bash -ic "export TITLE_DEFAULT='title 3'; cd ../../..; exec bash;"

Now open up a terminal and run the open_tabs.sh script:

./open_tabs.sh

Voila! It's magical! These 3 new tabs are now shown at the top of my terminal, and each has done the proper cd command I set, and each has the proper title I set!

This will all be placed into my dotfiles project: https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles.

Full and final solution: see here: Open Terminal with multiple tabs and execute application

Answer 2

I think you should use & to get your processes to run in background.

https://www.tecmint.com/run-linux-command-process-in-background-detach-process/