Simplest way to simulate a coin flip or toss on the Linux command line (in Bash; may work in other shells)

coinflip.bash

# return code is either 0 (success) or 1 (fail), so you can use it straight-up in logical statements
coinflip() { return $(($RANDOM%2)); }

coinflip && echo "heads" || echo "tails"

You can use the shuf command to do that

info '(coreutils) shuf invocation'
shuf -r -n 1 -e heads tails

True. I guess the advantage of mine is that you can directly use it in conditionals, and it has no external dependencies. Yours possibly also uses a higher quality source of randomness. Thanks for the tip regarding info '(coreutils) shuf invocation', I was only familiar with man primarily!