make secure passwords with bash

#!/bin/bash
LC_ALL=C tr -dc '[:alnum:]' < /dev/urandom | head -c ${1:-16}; echo;
# might be better to use [:graph:] for some websites.
# LC_ALL=C is the simplest local and overrides every LC setting. https://unix.stackexchange.com/questions/87745/what-does-lc-all-c-do
# tr convertes the output of /dev/urandom the cryptographically strong random device to alnum which is all characters
# and numbers. graph uses all printables except space
# this is then truncated using head to 16 characters
# Strangely enough this cuts off the infinite spew from urandom in the first half.