How can I automatically change terminal colors when I ssh a server?

I'm frequently logging into different servers from my os x terminal window.

I'd like to assign a color scheme for different hosts so that my terminal windows are easier to tell apart. Can this be done automatically?

Here's a complete solution. Keep a list of your servers ip addresses and/or domains and the colors you want for them in in ~/.server_colors:

192.168.122.102,Red Sands
192.168.122.103,Ocean
www.foo.com,Grass
foo.com,Grass

Then add this line to ~/.profile to hijack the ssh command:

alias ssh="~/bin/safe_ssh $1"

Then compare whatever's after the @ in your ssh target to your list. If there's a match, run an AppleScript to change the screen to the corresponding color. Here's ~/bin/safe_ssh:

#!/bin/bash
ip=`echo $1 | cut -d"@" -f2`
match=`cat ~/.server_colors | grep $ip | wc -l`
if [ $match -gt 0 ]
then
    color=`cat ~/.server_colors | grep $ip | cut -f2 -d","`
    osascript ~/bin/change_terminal_color.scpt "$color" 2>/dev/null
fi
/usr/bin/ssh $1

And last, here's ~/bin/change_terminal_color.scpt

on run argv
    tell application "Terminal" to set current settings of selected tab of window 1 to (first settings set whose name is (item 1 of argv))
end run

I took most of this code from this blog post.

The solution of @muirbot works really well for me. I made some little improvements to that. I'll add it below his post once I have enough reputation.

Replace the line

ip=echo $1 | cut -d"@" -f2

ip=echo $@ | grep -Eio [[:alnum:]_.-]+@[[:alnum:]_.-]+ | cut -d@ -f2

This change allows for giving additional arguments to your ssh command like "ssh -p 1111 userName@host"

The regular expression allows for simple ipv4 addresses and domain names.

To further support multiple arguments change the last line into

/usr/bin/ssh $@

Update 2021-03-03:

When you are having domains like example.com and www.example.com with different colors, then the script will not work as expected.

Make sure you place the shortest URL on top and then change

color=cat ~/.server_colors | grep $ip | cut -f2 -d","

color=cat ~/.server_colors | grep -m 1 $ip | cut -f2 -d","

The grep -m 1 command will stop when it finds the first match.

Yes.

Either you use e.g. "screen" and customize it: http://www.slac.stanford.edu/comp/unix/package/epics/extensions/iocConsole/screen.1.html

Or you manage to do it on your SSH Client, if possible.

You could also try this: http://www.cyberciti.biz/faq/bash-shell-change-the-color-of-my-shell-prompt-under-linux-or-unix/