A. Shell Summary

This appendix summarizes the main features of the standard POSIX shell as per IEEE Std 1003.1-2001.


The shell can be given the same options on the command line as can be specified with the set command. In addition, the following options can be specified:



The general format of a command typed to the shell is

command arguments

where command is the name of the program to be executed, and arguments are its arguments. The command name and the arguments are delimited by whitespace characters, normally the space, tab, and newline characters (changing the variable IFS affects this).

Multiple commands can be typed ...

Get Shell Programming in Unix, Linux and OS X, Fourth Edition now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.