Do nothing, returning a non-zero (false) exit status
`false' does nothing except return an exit status of 1, meaning
"failure". It can be used as a place holder in shell scripts where an
unsuccessful command is needed.
`false' ignores all command line arguments, since to do otherwise would change expected behavior that some programmers might be relying on.
"False in one thing, false in everything" ~ Legal maxim
true - Do nothing, successfully.
yes - Print a string until interrupted.