getopt
(1g)
Name
getopt - parse command options (enhanced)
Synopsis
getopt optstring parameters
getopt [options] [--] optstring parameters
getopt [options] -o|--options optstring [options] [--]
parameters
Description
User Commands GETOPT(1)
NAME
getopt - parse command options (enhanced)
SYNOPSIS
getopt optstring parameters
getopt [options] [--] optstring parameters
getopt [options] -o|--options optstring [options] [--]
parameters
DESCRIPTION
getopt is used to break up (parse) options in command lines
for easy parsing by shell procedures, and to check for legal
options. It uses the GNU getopt(3) routines to do this.
The parameters getopt is called with can be divided into two
parts: options which modify the way getopt will parse
(options and -o|--options optstring in the SYNOPSIS), and
the parameters which are to be parsed (parameters in the
SYNOPSIS). The second part will start at the first
non-option parameter that is not an option argument, or
after the first occurrence of `--'. If no `-o' or
`--options' option is found in the first part, the first
parameter of the second part is used as the short options
string.
If the environment variable GETOPT_COMPATIBLE is set, or if
its first parameter is not an option (does not start with a
`-', this is the first format in the SYNOPSIS), getopt will
generate output that is compatible with that of other ver-
sions 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 charac-
ters in arguments and non-option parameters. To solve this
problem, this implementation can generate quoted output
which must once again be interpreted by the shell (usually
by using the eval command). This has the effect of preserv-
ing those characters, but you must call 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
option (-T) can be used.
OPTIONS
-a, --alternative
Allow long options to start with a single `-'.
-h, --help
Output a small usage guide and exit successfully. No
other output is generated.
Linux Last change: May 31, 1997 1
User Commands GETOPT(1)
-l, --longoptions longopts
The long (multi-character) options to be recognized.
More than one option name may be specified at once, by
separating the names with commas. This option may be
given more than once, the longopts are cumulative.
Each long option name in longopts may be followed by
one colon to indicate it has a required argument, and
by two colons to indicate it has an optional argument.
-n, --name progname
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.
-o, --options shortopts
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 short options string. Each
short option character in shortopts may be followed by
one colon to indicate it has a required argument, and
by two colons to indicate it has an optional argument.
The first character of shortopts may be `+' or `-' to
influence the way options are parsed and output is gen-
erated (see section SCANNING MODES for details).
-q, --quiet
Disable error reporting by getopt(3).
-Q, --quiet-output
Do not generate normal output. Errors are still
reported by getopt(3), unless you also use -q.
-s, --shell shell
Set quoting conventions to those of shell. If no -s
argument is found, the BASH conventions are used. Valid
arguments are currently `sh' `bash', `csh', and `tcsh'.
-u, --unquoted
Do not quote the output. Note that whitespace and spe-
cial (shell-dependent) characters can cause havoc in
this mode (like they do with other getopt(1) implemen-
tations).
-T, --test
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 environment variable
GETOPT_COMPATIBLE is set, will return `--' and error
status 0.
Linux Last change: May 31, 1997 2
User Commands GETOPT(1)
-V, --version
Output version information and exit successfully. No
other output is generated.
PARSING
This section specifies the format of the second part of the
parameters of getopt (the parameters in the SYNOPSIS). The
next section (OUTPUT) describes the output that is gener-
ated. These parameters were typically the parameters a shell
function was called with. Care must be taken that each
parameter the shell function was called with corresponds to
exactly one parameter in the parameter list of getopt (see
the EXAMPLES). All parsing is done by the GNU getopt(3)
routines.
The parameters are parsed from left to right. Each parameter
is classified as a short option, a long option, an argument
to an option, or a non-option parameter.
A simple short option is a `-' followed by a short option
character. If the option has a required argument, it may be
written directly after the option character or as the next
parameter (ie. separated by whitespace on the command line).
If the option has an optional argument, it must be written
directly after the option character if present.
It is possible to specify several short options after one
`-', as long as all (except possibly the last) do not have
required or optional arguments.
A long option normally begins with `--' followed by the long
option name. If the option has a required argument, it may
be written directly after the long option name, separated by
`=', or as the next argument (ie. separated by whitespace on
the command line). If the option has an optional argument,
it must be written directly after the long option name, sep-
arated by `=', if present (if you add the `=' but nothing
behind it, it is interpreted as if no argument was present;
this is a slight bug, see the BUGS). Long options may be
abbreviated, as long as the abbreviation is not ambiguous.
Each parameter not starting with a `-', and not a required
argument of a previous option, is a non-option parameter.
Each parameter after a `--' parameter is always interpreted
as a non-option parameter. If the environment variable
POSIXLY_CORRECT is set, or if the short option string
started with a `+', all remaining parameters are interpreted
as non-option parameters as soon as the first non-option
parameter is found.
OUTPUT
Output is generated for each element described in the
Linux Last change: May 31, 1997 3
User Commands GETOPT(1)
previous section. Output is done in the same order as the
elements are specified in the input, except for non-option
parameters. Output can be done in compatible (unquoted)
mode, or in such way that whitespace and other special char-
acters within arguments and non-option parameters are pre-
served (see QUOTING). When the output is processed in the
shell script, it will seem to be composed of distinct ele-
ments that can be processed one by one (by using the shift
command in most shell languages). This is imperfect in
unquoted mode, as elements can be split at unexpected places
if they contain whitespace or special characters.
If there are problems parsing the parameters, for example
because a required argument is not found or an option is not
recognized, an error will be reported on stderr, there will
be no output for the offending element, and a non-zero error
status is returned.
For a short option, a single `-' and the option character
are generated as one parameter. If the option has an argu-
ment, the next parameter will be the argument. If the option
takes an optional argument, but none was found, the next
parameter will be generated but be empty in quoting mode,
but no second parameter will be generated in unquoted (com-
patible) mode. Note that many other getopt(1) implementa-
tions do not support optional arguments.
If several short options were specified after a single `-',
each will be present in the output as a separate parameter.
For a long option, `--' and the full option name are gener-
ated as one parameter. This is done regardless whether the
option was abbreviated or specified with a single `-' in the
input. Arguments are handled as with short options.
Normally, no non-option parameters output is generated until
all options and their arguments have been generated. Then
`--' is generated as a single parameter, and after it the
non-option parameters in the order they were found, each as
a separate parameter. Only if the first character of the
short options string was a `-', non-option parameter output
is generated at the place they are found in the input (this
is not supported if the first format of the SYNOPSIS is
used; in that case all preceding occurrences of `-' and `+'
are ignored).
QUOTING
In compatible mode, whitespace or 'special' characters in
arguments or non-option parameters are not handled cor-
rectly. As the output is fed to the shell script, the script
does not know how it is supposed to break the output into
separate parameters. To circumvent this problem, this
Linux Last change: May 31, 1997 4
User Commands GETOPT(1)
implementation offers quoting. The idea is that output is
generated with quotes around each parameter. When this out-
put is once again fed to the shell (usually by a shell eval
command), it is split correctly into separate parameters.
Quoting is not enabled if the environment variable
GETOPT_COMPATIBLE is set, if the first form of the SYNOPSIS
is used, or if the option `-u' is found.
Different shells use different quoting conventions. You can
use the `-s' option to select the shell you are using. The
following shells are currently supported: `sh', `bash',
`csh' and `tcsh'. Actually, only two `flavors' are distin-
guished: sh-like quoting conventions and csh-like quoting
conventions. Chances are that if you use another shell
script language, one of these flavors can still be used.
SCANNING MODES
The first character of the short options string may be a `-'
or a `+' to indicate a special scanning mode. If the first
calling form in the SYNOPSIS is used they are ignored; the
environment variable POSIXLY_CORRECT is still examined,
though.
If the first character is `+', or if the environment vari-
able POSIXLY_CORRECT is set, parsing stops as soon as the
first non-option parameter (ie. a parameter that does not
start with a `-') is found that is not an option argument.
The remaining parameters are all interpreted as non-option
parameters.
If the first character is a `-', non-option parameters are
outputted at the place where they are found; in normal oper-
ation, they are all collected at the end of output after a
`--' parameter has been generated. Note that this `--'
parameter is still generated, but it will always be the last
parameter in this mode.
COMPATIBILITY
This version of getopt(1) is written to be as compatible as
possible to other versions. Usually you can just replace
them with this version without any modifications, and with
some advantages.
If the first character of the first parameter of getopt is
not a `-', getopt goes into compatibility mode. It will
interpret its first parameter as the string of short
options, and all other arguments will be parsed. It will
still do parameter shuffling (ie. all non-option parameters
are outputted at the end), unless the environment variable
POSIXLY_CORRECT is set.
Linux Last change: May 31, 1997 5
User Commands GETOPT(1)
The environment variable GETOPT_COMPATIBLE forces getopt
into compatibility mode. Setting both this environment vari-
able and POSIXLY_CORRECT offers 100% compatibility for `dif-
ficult' programs. Usually, though, neither is needed.
In compatibility mode, leading `-' and `+' characters in the
short options string are ignored.
RETURN CODES
getopt returns error code 0 for successful parsing, 1 if
getopt(3) returns errors, 2 if it does not understand its
own parameters, 3 if an internal error occurs like
out-of-memory, and 4 if it is called with -T.
EXAMPLES
Example scripts for (ba)sh and (t)csh are provided with the
getopt(1) distribution, and are optionally installed in
/usr/local/share/getopt or /usr/share/getopt.
ENVIRONMENT
POSIXLY_CORRECT
This environment variable is examined by the getopt(3)
routines. If it is set, parsing stops as soon as a
parameter is found that is not an option or an option
argument. All remaining parameters are also interpreted
as non-option parameters, regardless whether they start
with a `-'.
GETOPT_COMPATIBLE
Forces getopt to use the first calling format as speci-
fied in the SYNOPSIS.
BUGS
getopt(3) can parse long options with optional arguments
that are given an empty optional argument (but can not do
this for short options). This getopt(1) treats optional
arguments that are empty as if they were not present.
The syntax if you do not want any short option variables at
all is not very intuitive (you have to set them explicitly
to the empty string).
AUTHOR
Frodo Looijaard <frodo@frodo.looijaard.name>
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
Linux Last change: May 31, 1997 6
User Commands GETOPT(1)
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | shell/gnu-getopt |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
getopt(3), bash(1), tcsh(1).
NOTES
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from http://soft-
ware.frodo.looijaard.name/getopt/files/getopt-1.1.5.tar.gz
Further information about this software can be found on the
open source community website at http://software.frodo.looi-
jaard.name/getopt/.
Linux Last change: May 31, 1997 7