Set avatar for Discord bot

avatar.sh

#!/bin/bash

# This script allows you to update the avatar for a Discord bot you created
# (regardless of whether your framework includes that feature or not). Discord
# uses the App Icon when you first create a bot, but after that it requires an
# API call if you want to change it. This script performs that API call.

if [ $# -lt 2 ]; then
    echo
    echo "Usage: $0 bot-token filename"
    echo
    echo "To get your bot token, got to the My Apps section of Discord, pull up your bot, look under APP BOT USER for the Token line. You may need to click a link to get the token to display."
    echo
    echo "Per the Discord API, filename should be a JPEG, PNG, or GIF image."
    echo
    exit 1
fi
if ! [ -r $2 ]; then
    echo "$2 is not readable"
    exit 2
fi

TYPE=$(file -b --mime-type $2)
DATA=$(base64 -w 0 $2)

# Run the cURL command and output to STDOUT, but grab the HTTP code in a variable
# Thanks https://superuser.com/a/862395/740441
exec 3>&1
HTTP_STATUS=$(curl -isw '%{http_code}' -o >(cat >&3) \
                   --request PATCH \
                   --header "Authorization: Bot $1" \
                   --header 'User-Agent: AvatarScript (https://gist.github.com/eslindsey/43560a77612e8e8dc703c93dafe371d9, 0.1)' \
                   --header 'Content-Type: application/json' \
                   --data "{\"avatar\":\"data:$TYPE;base64,$DATA\"}" \
                   'https://discordapp.com/api/users/@me')
echo
echo

if [ "$HTTP_STATUS" -ne 200 ]; then
    echo "ERROR: There was a problem setting the avatar."
    echo "The server's response is displayed above, which should tell you why the request failed."
    exit 3
fi

echo "SUCCESS: Avatar set successfully!"