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

xmas.sh

#!/bin/bash

STAR=$' \u2605'
FSLASH=$'\uFF0F'
BSLASH=$'\uFF3C'
ORNAMENTS="\u0069 \u0020 \u0020 \u0020 \u0020 \u0020
    \u0020 \u0020 \u0020 \u0020 \u0020 \u0020
    \u0020 \u2E1B \u2042 \u2E2E \u0026 \u0040 \uFF61"
ORNAMENT_COLORS="21 33 34 35 36 37"
HAT=$'\u005e'

tree() {
    h=$1
    printf "\n%*s\e[33m${STAR}\n" $h ""
    m=$((h * 2 - 1))
    for ((l=1; l <= h; l++)); do
        o=$((l * 2 - 2))
	s=$(((m - o) / 2 + 1))
        printf "%*s\e[32m${FSLASH}" $s ""
	for ((j=0; j < o; j++)); do
	    or=$(shuf -n1 -e $ORNAMENTS)
	    oc=$(shuf -n1 -e $ORNAMENT_COLORS)
            printf "\e[${oc}m$or"
        done
        printf "\e[32m${BSLASH}\n"
    done
    h1=$((h - 1))
    hat=$(printf "%*s" $h1)
    hats="\e[32m${hat// /$HAT}"
    printf " ${hats}|  |${hats}"
    if (($h > 10)); then
        printf "\n %*s|  |%*s" $h1 "" $h1 ""
    fi
    printf "\n\n"
}

tree 20