Bash is still included with Catalina, but is no longer the default shell when you launch terminal, ZSH is. You can still call bash scripts by using #!/bin/bash at the top of your script. As far as the OP's script not running, it likely has to do with macOS privacy controls.

• Bash is a Unix shell, which is a command line interface (CLI) for interacting with an operating system (OS). Any command that you can run from the command line can be used in a bash script. Scripts are used to run a series of commands. Bash is available by default on Linux and macOS operating systems.
• A Guide for Upgrading macOS to Catalina and Migrating the Default Shell from Bash to Zsh. Tagged with macos, catalina, zsh, bash.

Terminal User Guide

Instead of entering commands and waiting for a response, you can compose shell scripts that run without direct interaction.

A shell script is a text file that contains one or more UNIX commands. You run a shell script to perform commands you might otherwise enter at the command line.

Shell scripts are useful because you can combine many common tasks into one script, saving you time and possible errors when performing similar tasks over and over. You can also automate shell scripts using tools such as launchd or Apple Remote Desktop.

A shell script begins with a character combination that identifies it as a shell script—specifically the characters # and ! (together called a shebang) followed by a reference to the shell the script should be run with. For example, here’s the first line of a shell script that would be run with sh:

How To Write A Bash Script For Macos Catalina Full

You should document your shell scripts with comments. To add a comment, start the line with the number sign (#). Every line of a comment needs to begin with the number sign:

How To Write A Bash Script For Macos Catalina Bay

You can put blank lines in a shell script to help visually distinguish different sections of the script.

You use the chmod tool to indicate that the text file is executable (that is, its contents can run as a program). See Make a file executable in Terminal on Mac.

How To Write A Bash Script For Macos Catalina Version

For information about how to write shell scripts, see the Shell Scripting Primer on the Apple Developer Connection website.

Bash Script For Loop