Use a Modern Bash Shell on macOS

macOS ships with an older version of the Bash shell, because newer versions use a license that makes it more difficult for Apple to integrate into their OS. In macOS Catalina, Apple changed the default shell to ZSH for this reason.

But by using Homebrew, you can install the latest version of Bash and use its features.

What You Need

To complete this tutorial, you’ll need Homebrew installed, which you can do by following the Install Homebrew tutorial.

Finding Your Current Bash Version

First, check your current Bash version:

echo $BASH_VERSION

If you see a version like the following, you’re running a very old version:

3.2.57(1)-release

Use Homebrew to get a newer version.

Installing the Latest Bash with Homebrew

Ensure you have Homebrew installed, which you can do by following Installing Homebrew.

Then use Homebrew to install Bash:

brew install bash

To see where Homebrew installed Bash, run the following command:

ls "$(brew --prefix)/bin/bash"

You’ll see a result similar to this:

/usr/local/bin/bash

On M1 macs, the path will be /opt/local/homebrew/bin/bash instead.

Next, add the path to Homebrew’s version of Bash to the /etc/shells file. Display the contents of the file to ensure that it’s not already listed:

cat /etc/shells

You’ll see something like this:

# 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/ksh
/bin/sh
/bin/tcsh
/bin/zsh

Use the following command to add the newer version of Bash to the /etc/shells file:

echo "$(brew --prefix)/bin/bash" | sudo tee -a /etc/shells

Since the file is owned by the administrator, you can’t redirect text using standard redirection, but you can work around it by using tee to send output to a file as it’s run with sudo. The -a flag appends text rather than overwriting the existing file.

Ensure the file now contains the new shell:

cat /etc/shells

You’ll find the new shell at the end of the file:

# 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/ksh
/bin/sh
/bin/tcsh
/bin/zsh
/usr/local/bin/bash

Now you can change your shell.

Switching to the Newest Bash Shell

To switch shells, use the chsh command to change the shell for your user. Use the following command to specify the version you installed with Homebrew:

chsh -s "$(brew --prefix)/bin/bash"

The system will prompt you for your password. Enter it and your shell will change:

Changing shell for brianhogan.
Password for brianhogan:

The current shell doesn’t change, so open a new Terminal and use the following command to check your Bash version:

echo $BASH_VERSION

You’ll see the newer version appear:

5.0.11(1)-release

You now have the latest version installed.

To change back to the system-installed version of Bash, use chsh -s /bin/bash.

Conclusion

You’ve changed your shell to the latest version of Bash, and you know how to change it back to the default. You can use the same approach to install the latest version of ZSH, or other shells like Fish. Install the shell, add the path to its binary to /etc/shells, and use chsh to switch the shell.