How to change your shell in Linux

Sometimes you want to change your default shell on your Linux system to a different one. This is a step-by-step guide.

✅ Check Your Current Shell

You can check what shell you’re currently using with:

echo $SHELL

You can also view the default login shell for your user by checking /etc/passwd:

grep "^$USER" /etc/passwd

🔄 Change Your Default Shell (per user)

To change your default shell, use the chsh (change shell) command:

chsh -s /path/to/shell

• The -s option means “set shell”.
• The change applies at next login.
• You’ll likely be prompted for your user password.

⚠️ Common Issue

If you see this error:

chsh: /bin/fish is an invalid shell

…it means the shell binary is not listed in /etc/shells (the list of allowed login shells).

You can inspect it with:

cat /etc/shells

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📦 Installing Zsh and Fish on Ubuntu

First, update your package list:

sudo apt update

Then install either shell:

🌀 Install Zsh:

sudo apt install zsh

🐟 Install Fish:

sudo apt install fish

Check again:

cat /etc/shells

Example output:

/bin/zsh
/usr/bin/zsh
/usr/bin/fish

NOTE

• fish is not considered essential for boot/recovery, so it’s installed in /usr/bin.
• This follows Linux conventions: essential tools → /bin, user-space tools → /usr/bin.

Now set your default shell:

chsh -s /bin/zsh     # For Zsh
chsh -s /usr/bin/fish  # For Fish

Logout and log back in to see the change.

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👥 Changing Shell for Another User (as root)

If you’re root, you can change another user’s shell like this:

sudo chsh -s /bin/bash carlos

Or, more dangerously, by editing /etc/passwd manually (not recommended).

# Be cautious with:
sudo nano /etc/passwd

👀 Prompt Differences Between Bash, Zsh, and Fish (Quick Peek)

One of the most obvious differences between the different shells is the prompt

Bash prompt

• Classical

• It is customizable via .bashrc.

  

Fish prompt

• Colorful
• Auto-suggestions by default

Zsh prompt

• Support themes like agnoster, robbyrussell

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Related Note

Customizing Your Linux Shell: Oh My Zsh, Oh My Bash, and Prompt Styling