Linux getopt Command

What is Linux getopt Command?

In this tutorial we learn how to use getopt command in Linux. getopt command is getopt - parse command options (enhanced).

getopt Syntax

getopt optstring parameters
getopt [options] [--] optstring parameters
getopt [options] -o|--options optstring [options] [--] parameters

The parameters getopt is called with can be divided into two parts: options which modify the way getopt will do the parsing (the options and the optstring in the SYNOPSIS), and the parameters which If the environment variable GETOPT_COMPATIBLE is set, or if the first parameter is not an option (does not start with a ‘-’, the first format in the SYNOPSIS), getopt will generate output that is compatible with that of other versions of getopt(1). It will still do parameter shuffling and recognize optional arguments (see section COMPATIBILITY for more information). Traditional implementations of getopt(1) are unable to cope with whitespace and other (shell-specific) special characters in arguments and non-option parameters. To solve this problem, this imple‐ getopt in a way that is no longer compatible with other versions (the second or third format in the SYNOPSIS). To determine whether this enhanced version of getopt(1) is installed, a special test The name that will be used by the getopt(3) routines when it reports errors. Note that errors of getopt(1) are still reported as coming from getopt. The short (one-character) options to be recognized. If this option is not found, the first parameter of getopt that does not start with a ‘-’ (and is not an option argument) is used as the Disable error reporting by getopt(3). Do not generate normal output. Errors are still reported by getopt(3), unless you also use -q. Test if your getopt(1) is this enhanced version or an old version. This generates no output, and sets the error status to 4. Other implementations of getopt(1), and this version if the en‐ Do not quote the output. Note that whitespace and special (shell-dependent) characters can cause havoc.

getopt Examples

getopt Command Manual / Help

We can use man and info command to see the manual page of getopt command. getopt command also have --help option to show list of options.

To open man page for getopt command we can use command below. To exit man or info page you can press q.

man getopt

To open info page for getopt command we can use command below.

info getopt

To open help page from getopt command we can run command below.

getopt --help