Recent versions of macOS now use zsh as the default command line shell. I typically use the bash shell on Linux servers, so I prefer using it on my Mac. However, zsh is a very good shell to use, especially for interactive use.

This post is going to describe how to switch from the zsh shell to the bash shell.

Before Starting

You should be familiar with using the macOS Terminal command line.

I am using Homebrew to install the latest bash version. The version that comes with macOS is very old, and it’s not being updated because of licensing issues. Homebrew is very easy to install; please refer to their website for instructions.

You may need to update your PATH variable to ensure that the path for Homebrew executables is at the beginning of your PATH:

$ echo $PATH
/opt/homebrew/bin:/usr/bin:/bin:/usr/sbin:/sbin/...

## If not, do:

$ PATH=/opt/homebrew/bin:$PATH

You can update your PATH at the beginning of your .bashrc file to make it permanent. After doing so, restart your terminal session (we’ll talk more about the .bashrc file).

If you are using zsh, update your PATH variable in your .zshrc file.

Install the bash Executable

First install bash and then update /etc/shells with the path to the newly installed bash version. This file contains the list of valid shells that a user may switch to. You must change to the root user to update this file.

$ brew install bash

$ sudo -i
Password:
mac1:~ root# echo /opt/homebrew/bin/bash >> /etc/shells
mac1:~ root# exit
logout

When sudo prompts you for a password, enter your user password. Verify that you have correctly updated /etc/shells.

$ cat /etc/shells
# List of acceptable shells for chpass(1).
# Ftpd will not allow users to connect who are not using
# one of these shells.

/bin/bash
/bin/csh
/bin/dash
/bin/ksh
/bin/sh
/bin/tcsh
/bin/zsh
/opt/homebrew/bin/bash

Activate the Homebrew bash Shell

Do the following to switch to the new shell.

$ chsh -s /opt/homebrew/bin/bash
Changing shell for george.
Password for george:

Restart your terminal session. Then you can verify that your new shell is active:

$ echo $SHELL
/opt/homebrew/bin/bash

Tweak the .profile and .bashrc Environment

Now that your bash shell is working, you will want to start customizing your shell environment. Here are some suggestions to get started with. The following .profile and .bashrc files will create a two-line shell prompt, command line aliases for the ls (list files) command, and set up some command history options.

Here is the .profile file:

# if running bash
if [ -n "$BASH_VERSION" ]; then
    # include .bashrc if it exists
    if [ -f "$HOME/.bashrc" ]; then
        . "$HOME/.bashrc"
    fi
fi

# user@system:~/user/working/directory
# $
PS1="\e[0;32m\u@\h\e[m:\w\n$ "

Here is the .bashrc file:

PATH=$HOME/bin:/opt/homebrew/bin:/opt/homebrew/sbin:$PATH

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

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

alias l='ls -CFG'
alias la='ls -AFG'
alias ll='ls -alFG'

Be sure to restart your terminal session after making any changes to your bash shell environment. Here are some examples for using the ls aliases:

george@macair1:~
$ mkdir tmpdir

george@macair1:~
$ cd tmpdir

george@macair1:~/tmpdir
$ touch .dotfile tmpfile

george@macair1:~/tmpdir
$ l
tmpfile
george@macair1:~/tmpdir

$ la
.dotfile  tmpfile

george@macair1:~/tmpdir
$ ll
total 0
drwxr-xr-x   4 george  staff   128 Apr  8 11:40 ./
drwxr-x---+ 54 george  staff  1728 Apr  8 16:26 ../
-rw-r--r-- 1 george  staff     0 Apr  8 11:40 .dotfile
-rw-r--r-- 1 george  staff     0 Apr  8 11:40 tmpfile

Final Thoughts

When a new Homebrew bash version becomes available (as noted by running brew update), be sure to only upgrade the bash package by doing:

$ brew upgrade bash

Then immediately restart your terminal session. Afterwards, you can upgrade any remaining brew packages.