Change terminal colour based on SSH session

Question

Is it possible to automatically change the color of the terminal based on which server I am connected to through SSH?

For instance, when I fire up the terminal it has the standard colors defined under my profile. Then I ssh to ssh.example.com and the color changes to black & green instead. Then I exit the session and the color returns to the standard color theme.

I know that you could do this manually. But I'm looking for an automated way.

Answer 1

Yes, you can by changing the PS1 value in .bashrc file on every hostname where you are connecting with ssh.

See this answer to view how to costumize as you like the bash changing the PS1 value.

On my machine (radu@Radu) I have in .bashrc:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;35m\]\u@\h\[\033[00m\]:\[\033[01;34m\] \w\[\033[01;37m\] > '

On the hosted machine (radu@ubuntu) I have:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;35;40m\]\u@ubuntu\[\033[00;40m\]:\[\033[01;34;40m\] \w\[\033[01;32;40m\] > '

Answer 2

If you are using xterm, this works great: https://github.com/fboender/sshbg

How does it work?

Black unix magic. Well, not really. Well, kinda...

SSH lets you run a local command before the connection to the remote host is established. Some terminals allow you to set the background color with an escape sequence. It's possible to detect if the SSH command has exited from the locally executed command by polling the parent process PID in the background. Combine the three and presto! Background colors.

sshbg matches (regex) entries in a configuration file against the provided hostname. That results in a profile name, which has a background color associated with it. See the "Config file" section at the bottom of this page for more info.

Installation and usage

Requirements:

• Python v3.x+
• A supported terminal

Clone this repo:

git clone [email protected]:fboender/sshbg.git
cd sshbg

Copy the sshbg script to some dir in your PATH, for example:

sudo cp sshbg /usr/local/bin/

Copy the sshbg.conf file to ~/.config/sshbg.conf:

cp sshbg.conf ~/.config/

Enable the LocalCommand configuration setting in your SSH config. You can do this on a host-by-host basis, or with wildcards. To enable it for all hosts, make your SSH config look like this:

$ cat ~/.ssh/config
PermitLocalCommand yes
Host *
    LocalCommand sshbg "%n"