A simple CLI password generator built on /dev/urandom and Unix tools

pwgen.sh

#!/bin/bash

# A simple password generator that uses a combination of /dev/urandom,
# tr, head, and xclip to quickly generate a reasonably random password

## strict bash mode
set -euo pipefail
IFS=$'\n\t'

## pwgen [count] [allowed-symbols]

### password length is 16 by default
readonly COUNT=${1:-16}

### use all symbols by default
readonly SYMBOLS=${2:-'/\-[]{};:",.<>?!@#$%^&*()=+\\'"'"}

### if you provide a non-empty value for the allowed symbols,
### guarantee that as least alphanumeric character will be in the
### password
readonly BASE_SYMBOLS='A-Za-z0-9'
readonly FULL_SYMBOLS="$BASE_SYMBOLS""$SYMBOLS"

## store generated password in clipboard
readonly PASS=$(< /dev/urandom tr -dc "$FULL_SYMBOLS" | head -c"$COUNT")
echo -n "$PASS" | xclip -sel clip