Generate ULID in bash

generate-ulid.sh

#!/bin/bash

# taken from https://www.usefulids.com/resources/generate-ulid-in-bash

# Function to convert timestamp to ULID-compatible format
timestamp_to_ulid() {
  local timestamp=$1
  # ULID timestamp is milliseconds since UNIX epoch
  printf '%010X' $((timestamp * 1000))
}

# Function to generate random part of ULID
random_part() {
  # Generate 16 random bytes and encode them in base32 (remove padding)
  openssl rand -out /dev/stdout -hex 10 | xxd -r -p | base32 | tr -d '=' | head -c 16
}

# Get current timestamp in milliseconds
current_timestamp=$(date +%s)

# Convert timestamp to ULID-compatible format
timestamp_ulid=$(timestamp_to_ulid $current_timestamp)

# Generate random part of ULID
random_ulid=$(random_part)

# Combine timestamp and random part to form ULID
ulid="${timestamp_ulid}${random_ulid}"

echo $ulid