Changes iTerm2's background color based on host configuration

ssh-background

#!/usr/bin/env bash
# Installation:
# 1. Save this script to /some/bin/ssh-background
# 2. chmod 755 /some/bin/ssh-background
# 3. alias ssh='. /some/bin/ssh-background'
# 4. Configure your host colors below.
# 5. Define environment variables ssh_<colour>=( host1 hostmatch1 ... )
# 6. Or just type ssh <colour> hostname

set_color() {
    local HEX_FG=$1
    local HEX_BG=$2
    local OPACITY=$3
    if [[ "$TERM_PROGRAM" != "iTerm.app" ]]; then
        return
    fi

    local FG_R=`echo $HEX_FG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$1 * 257)}'`
    local FG_G=`echo $HEX_FG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$2 * 257)}'`
    local FG_B=`echo $HEX_FG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$3 * 257)}'`
    local BG_R=`echo $HEX_BG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$1 * 257)}'`
    local BG_G=`echo $HEX_BG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$2 * 257)}'`
    local BG_B=`echo $HEX_BG | sed 's/../0x&,/g' | awk -F "," '{printf("%d",$3 * 257)}'`

    /usr/bin/osascript <<EOF
    tell application "iTerm"
        tell current session of current terminal
        set foreground color to {$FG_R, $FG_G, $FG_B}
        set background color to {$BG_R, $BG_G, $BG_B}
        set transparency to "$OPACITY"
        end tell
    end tell
EOF
}

bgc=( ffffff ffe5e9 e9ffe5 e5e9ff f0f0f0 000000 )
fgc=( 000000 000000 000000 000000 000000 111111 )
trn=( 0 0 0 0 0 0 )
names=( white red green blue grey black )

index=-1
colour_index=-1
for colour in ${names[@]}; do
    ((colour_index += 1))
    if [[ "$1" == "$colour" ]]; then
        index=$colour_index
        shift 1
        break
    fi
    vname="ssh_${colour}[@]"
    for machine_prefix in ${!vname}; do
        if [[ "$@" =~ "$machine_prefix" ]]; then
            index=$colour_index
            break
        fi
        [[ $index -ge 0 ]] && break
    done
done

if [[ index -ge 0 ]]; then
    set_color ${fgc[$index]} ${bgc[$index]} ${trn[$index]}
fi

echo ssh $@
\ssh $@

set_color 000000 ffffff 0.0