Learning the Korn Shell

Appendix B. Reference Lists

Invocation Options

Here is a list of the options you can use when invoking the Korn shell. In addition to these, any set option can be used on the command line; see the table on options later in this appendix. Login shells are usually invoked with the options -i (interactive), -s (read from standard input), and -m -able job control).

Option	Meaning
-c string	Execute string, then exit.
-s	Read commands from the standard input. If an argument is given, this flag takes precedence (i.e., the argument won’t be treated as a script name and standard input will be read).
-i	Interactive shell. Ignore signals TERM, INTR, and QUIT.
-r	Restricted shell. See Chapter 10.

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. ...