Get a list of all shell built-ins

$ help --help
# or $ help help :)

help: help [-dms] [pattern ...]
    Display information about builtin commands.

    Displays brief summaries of builtin commands.  If PATTERN is
    specified, gives detailed help on all commands matching PATTERN,
    otherwise the list of help topics is printed.

    Options:
      -d        output short description for each topic
...Copy

$ help -d '*'

Shell commands matching keyword `*'

% - Resume job in foreground.
(( ... )) - Evaluate arithmetic expression.
. - Execute commands from a file in the current shell.
: - Null command.
[ - Evaluate conditional expression.
[[ ... ]] - Execute conditional command.
alias - Define or display aliases.
bg - Move jobs to the background.
bind - Set Readline key bindings and variables.
break - Exit for, while, or until loops.
builtin - Execute shell builtins.
caller - Return the context of the current subroutine call.
case - Execute commands based on pattern matching.
cd - Change the shell working directory.
...
until - Execute commands as long as a test does not succeed.
variables - Common shell variable names and usage.
wait - Wait for job completion and return exit status.
while - Execute commands as long as a test succeeds.
{ ... } - Group commands as a unit.Copy

$ type cd

cd is a shell builtin

$ type cp

cp is /usr/bin/cp
# cp is not a shell built-inCopy