Quickly create a visual representation of a hash checksum in bash using Unicode color-coded characters

visual_hash.sh

#!/bin/bash

# outputs a visual hash for the system is running on:
# useful to identify which system you are running your commands on

# first two bytes for the unicode sequence, by default we use 28
# since the braille character set is fully compliant and easy to identify
# the characters will be: u+${BASE_UNICODE}${first_hex}${second_hex}
# good values are: 14, 22, 25, 28, 2F, 34, A5, FB, 106, 131
BASE_UNICODE=14

# create a temp file for the system info
FILE_TMP=$(mktemp)

# gather some info to identify the system
hostname -f > "$FILE_TMP"
ip link show 2>/dev/null | grep link | awk {'print $2'} | sort  >> "$FILE_TMP"
lspci 2>/dev/null | sort  >> "$FILE_TMP"
grep bogomips /proc/cpuinfo | head -n1 >> "$FILE_TMP"
find /sys -print | sort >> "$FILE_TMP"
head -n4096 /dev/sda >> "$FILE_TMP"
date >> "$FILE_TMP"

# calculate a checksum of the system info
SUM=$(md5sum "$FILE_TMP" | cut -b1-32)
#SUM=$(sha256sum "$FILE_TMP" | cut -b1-64)

# we don't need the info anymore
rm -f "$FILE_TMP"

# create an empty visual sum to start with
VISUAL_SUM=""

# iterate over the checksum
for (( i=0; i<${#SUM}; i++ )); do
        first=${SUM:$i:1}       # get the first hex value
        (( i++ ))
        second=${SUM:$i:1}  # get the second hex value
        if [ -z "$second" ]; then
                second=0  # default value
        fi

        (( i++ ))
        color=${SUM:$i:1}  # get the color shade hex value

        if [ -z "$color" ]; then
                CL="\[\e[90;40m\]"  # default value
        else
                # if we have data, we convert it to a bash color code
                case $color in
                        0)
                                CL="\[\e[30;39m\]"
                                ;;
                        1)
                                CL="\[\e[31;40m\]"
                                ;;
                        2)
                                CL="\[\e[32;40m\]"
                                ;;
                        3)
                                CL="\[\e[33;40m\]"
                                ;;
                        4)
                                CL="\[\e[34;40m\]"
                                ;;
                        5)
                                CL="\[\e[35;40m\]"
                                ;;
                        6)
                                CL="\[\e[36;40m\]"
                                ;;
                        7)
                                CL="\[\e[37;40m\]"
                                ;;
                        8)
                                CL="\[\e[90;40m\]"
                                ;;
                        9)
                                CL="\[\e[91;40m\]"
                                ;;
                        [aA])
                                CL="\[\e[92;40m\]"
                                ;;
                        [bB])
                                CL="\[\e[93;40m\]"
                                ;;
                        [cC])
                                CL="\[\e[94;40m\]"
                                ;;
                        [dD])
                                CL="\[\e[95;40m\]"
                                ;;
                        [eE])
                                CL="\[\e[96;40m\]"
                                ;;
                        [fF])
                                CL="\[\e[97;40m\]"
                                ;;
                        *)
                                CL="\[\e[0m\]"
                                ;;
                esac
        fi

        # queue up the current character
        VISUAL_SUM="${VISUAL_SUM}${CL}$(echo -e "\u${BASE_UNICODE}${first}${second}")"
done

echo $VISUAL_SUM