#

| Appendix B Reference Lists |

## B.2 Built-in Commands and Keywords

Here is a summary of all built-in commands and keywords.

Command | Chapter | Summary
--- | --- | ---
: | 7 | Do nothing (just do expansions of arguments).
. | 4 | Read file and execute its contents in current shell.
alias | 3 | Set up shorthand for command or command line.
bg | 8 | Put job in background.
break | 5 | Exit from surrounding for, select, while, or until loop.
case | 5 | Multi-way conditional construct.
cd | 1 | Change working directory.
continue |  | Skip to next iteration of for, select, while, or until loop.
echo | 4 | Expand and print arguments (obsolete).
exec | 9 | Replace shell with given program.
exit | 5 | Exit from shell.
export | 3 | Create environment variables.
eval | 7 | Process arguments as a command line.
fc | 2 | Fix command (edit history file).
fg | 8 | Put background job in foreground.
for | 5 | Looping construct.
function | 4 | Define function.
getopts | 6 | Process command-line options.
if | 5 | Conditional construct.
jobs | 1 | List background jobs.
kill | 8 | Send signal to process.
let | 6 | Arithmetic variable assignment.
newgrp |  | Start new shell with new group ID.
print | 1 | Expand and print arguments on standard output.
pwd | 1 | Print working directory.
read | 7 | Read a line from standard input.
readonly | 6 | Make variables read-only (unassignable).
return | 5 | Return from surrounding function or script.
select | 5 | Menu generation construct.
set | 3 | Set options.
shift | 6 | Shift command-line arguments.
time |  | Run command and print execution times.
trap | 8 | Set up signal-catching routine.
typeset | 6 | Set special characteristics of variables.
ulimit | 10 | Set/show process resource limits.
umask | 10 | Set/show file permission mask.
unalias | 3 | Remove alias definitions.
unset | 3 | Remove definitions of variables or functions.
until | 5 | Looping construct.
wait | 8 | Wait for background job(s) to finish.
whence | 3 | Identify source of command.
while | 5 | Looping construct.

B.1 Invocation Options |  | B.3 Built-in Shell Variables