If you aren’t a Linux user and you watch someone who knows what they are doing use Bash — the popular command line interpreter — you might get the impression they type much faster than they actually ...

While Linux systems install with thousands of commands, bash also supplies a large number of “built-ins”—commands that are not sitting in the file system as separate files, but are part of bash itself ...

You probably use some bash builtins fairly often whether or not you think of them as builtins or simply as commands. After all, bash builtins are commands, but not implemented as separate executables.