bash: "command not found" when calling function defined in ~/.bashrc file in `bash -c` command while opening gnome-terminal 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

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 -c "source $HOME/.bashrc && set-title hey; exec bash"
gnome-terminal --tab -- bash -c "cd ~; 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! I get this error in that tab that opens:

bash: set-title: command not found

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!? I've tried exporting and sourceing and just don't know what I'm doing wrong here.

Related:

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

Answer 1

To get bash to read and execute ~/.bashrc on startup, start it as an interactive shell:

gnome-terminal --tab -- bash -ic "set-title hey; exec bash"

Now why didn’t your approach of sourcing the file in a non-interactive shell work? I strongly assume your ~/.bashrc begins with something like this:

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

This lets it return without doing anything if the shell where it is sourced doesn’t have “i” anywhere in its $-, i.e. it’s an interactive shell. $- is a special parameter, man bash says:

- Expands to the current option flags as specified upon invocation, by the set builtin command, or those set by the shell itself (such as the -i option).