https://gist.github.com/1011836 を bashで

xmas.sh

#!/bin/bash

STAR=$' \u2605'
FSLASH=$'\uFF0F'
BSLASH=$'\uFF3C'
ORNAMENTS=(0069 0020 0020 0020 0020 0020
    0020 0020 0020 0020 0020 0020
    0020 2E1B 2042 2E2E 0026 0040 FF61)
ORNAMENT_COLORS=(21 33 34 35 36 37)
HAT='^'

tree() {
    h=$1
    printf "\n%${h}s\e[33m${STAR}\n"
    m=$((h * 2 - 1))
    eval set {1..$h}
    for l; do
        o=$((l * 2 - 2))
	s=$(((m - o) / 2 + 1))
        printf "%${s}s\e[32m${FSLASH}"
	for ((j=0; j < o; j++)); do
            or=${ORNAMENTS[${#ORNAMENTS[@]}*$RANDOM/32767]}
            oc=${ORNAMENT_COLORS[${#ORNAMENT_COLORS[@]}*$RANDOM/32767]}
            printf "\e[${oc}m\u$or"
        done
        printf "\e[32m${BSLASH}\n"
    done
    h1=$((h - 1))
    spaces=$(printf "%*s" $h1)
    hats="\e[32m${spaces// /$HAT}"
    printf " ${hats}|  |${hats}"
    if (($h > 10)); then
        printf "\n $spaces|  |$spaces"
    fi
    printf "\n\n"
}

tree 20