Custom Prompt When Connected Over SSH

Table of Contents

I use zsh with a theme called robbyrussell that makes my prompt very minimalistic. I already know who I am, and what machine I’m on, so the standard user@host prompt is just noisy.

➜  ~ echo "Hello"

I quite like it, except when I SSH to my main machine at work, then it suddenly becomes difficult to remember which terminal is which.

Let’s prefix my prompt with the hostname, but only if I’m connected over SSH.

Customizing the prompt #

TL;DR: Add this snippet to your ~/.zshrc or ~/.bashrc (on the remote machine)

if [[ -n $SSH_CONNECTION ]] ; then
    PS1="[$(hostname)] $PS1"
fi

And your prompt will look like this when you connect to it

[some-pc-name] ➜  ~ echo "Hello"

But why stop there? It’s always nice with a bit of flair! So I came up with this:

if [[ -n $SSH_CONNECTION ]]; then
    hostname_string="%{$fg_bold[blue]%}[%{$fg_bold[yellow]%}%U$(hostname)%u%{$fg_bold[blue]%}]%{$reset_color%}"
    PS1="$hostname_string $PS1"
fi

And how we end up with this when I SSH into my laptop.

Ant that’s good enough for me.

How does it work? #

SSH_CONNECTION is an environment variable that is set when you connect via SSH. We’re just using it as a flag, but it contains the IP of the remote and local machine (see man ssh).

PS1 is another environment variable, the primary prompt string. This string is what defines your prompt.

In the first example, I’m simply prepending the existing PS1 variable with [$(hostname)]. In the second example, it’s a bit more complicated. There hostname_string is formatted according to the section EXPANSION OF PROMPT SEQUENCES in man zshmisc.

But we also make use of the variables fg_bold and reset_color. Which you can read more about in man zshcontrib under OTHER FUNCTIONS.

Customizing the prompt #

How does it work? #

Further reading #