How do I make the apple terminal window auto change colour scheme when I ssh to a specific server

Question

When I ssh into a remote production server I would like the colour scheme of my terminal window to change to something brigh and scary, preferably red, to warn me that I am

Answer 1

Here's a combined solution based on a couple of existing answers that handles the exit. Also includes a little extra if you don't want to deal with 16 bit color values.

This should be put in your ~/.bash_profile

# Convert 8 bit r,g,b,a (0-255) to 16 bit r,g,b,a (0-65535)
# to set terminal background.
# r, g, b, a values default to 255
set_bg () {
    r=${1:-255}
    g=${2:-255}
    b=${3:-255}
    a=${4:-255}

    r=$(($r * 256 + $r))
    g=$(($g * 256 + $g))
    b=$(($b * 256 + $b))
    a=$(($a * 256 + $a))

    osascript -e "tell application \"Terminal\" to set background color of window 1 to {$r, $g, $b, $a}"
}

# Set terminal background based on hex rgba values
# r,g,b,a default to FF
set_bg_from_hex() {
    r=${1:-FF}
    g=${2:-FF}
    b=${3:-FF}
    a=${4:-FF}

    set_bg $((16#$r)) $((16#$g)) $((16#$b)) $((16#$s))
}

# Wrapping ssh command with extra functionality
ssh() {
    # If prod server of interest, change bg color
    if ...some check for server list
    then
        set_bg_from_hex 6A 05 0C
    end

    # Call original ssh command
    if command ssh "$@"
    then
        # on exit change back to your default
        set_bg_from_hex 24 34 52
    fi
}

• set_bg - takes 4 (8 bit) color values
• set_bg_from_hex - takes 4 hex values. most of my color references I use are in hex, so this just makes it easier for me. It could be taken a step further to actually parse #RRGGBB instead of RR GG BB, but it works well for me.
• ssh - wrapping the default ssh command with whatever custom logic you want. The if statement is used to handle the exit to reset the background color.