User Commands getopts(1)
NAME
getopts - parse utility options
SYNOPSIS
/usr/bin/getopts optstring name [arg...]
sh
getopts optstring name [argument]...
ksh
getopts optstring name [arg]...
ksh93
getopts [-a name] optstring name [arg]...
DESCRIPTION
/usr/bin/getopts
The getopts utility can be used to retrieve options and
option-arguments from a list of parameters.
Each time it is invoked, the getopts utility places the
value of the next option in the shell variable specified by
the name operand and the index of the next argument to be
processed in the shell variable OPTIND. Whenever the shell
is invoked, OPTIND is initialized to 1.
When the option requires an option-argument, the getopts
utility places it in the shell variable OPTARG. If no option
was found, or if the option that was found does not have an
option-argument, OPTARG is unset.
If an option character not contained in the optstring
operand is found where an option character is expected, the
shell variable specified by name is set to the question-mark
( ? ) character. In this case, if the first character in
optstring is a colon (:, the shell variable OPTARG is set to
the option character found, but no output is written to
standard error; otherwise, the shell variable OPTARG is
unset and a diagnostic message is written to standard error.
This condition is considered to be an error detected in the
way arguments were presented to the invoking application,
but is not an error in getopts processing.
SunOS 5.11 Last change: 2 Nov 2007 1
User Commands getopts(1)
If an option-argument is missing:
o If the first character of optstring is a colon, the
shell variable specified by name is set to the
colon character and the shell variable OPTARG is
set to the option character found.
o Otherwise, the shell variable specified by name is
set to the question-mark character (?), the shell
variable OPTARG is unset, and a diagnostic message
is written to standard error. This condition is
considered to be an error detected in the way argu-
ments were presented to the invoking application,
but is not an error in getopts processing; a diag-
nostic message is written as stated, but the exit
status is zero.
When the end of options is encountered, the getopts utility
exits with a return value greater than zero; the shell vari-
able OPTIND is set to the index of the first non-option-
argument, where the first -- argument is considered to be an
option-argument if there are no other non-option-arguments
appearing before it, or the value $# ] 1 if there are no
non-option-arguments; the name variable is set to the
question-mark character. Any of the following identifies the
end of options: the special option --, finding an argument
that does not begin with a -, or encountering an error.
The shell variables OPTIND and OPTARG are local to the
caller of getopts and are not exported by default.
The shell variable specified by the name operand, OPTIND and
OPTARG affect the current shell execution environment.
If the application sets OPTIND to the value 1, a new set of
parameters can be used: either the current positional param-
eters or new arg values. Any other attempt to invoke getopts
multiple times in a single shell execution environment with
parameters (positional parameters or arg operands) that are
not the same in all invocations, or with an OPTIND value
modified to be a value other than 1, produces unspecified
results.
sh
getopts is a built-in Bourne shell command used to parse
positional parameters and to check for valid options. See
sh(1). It supports all applicable rules of the command syn-
tax standard (see Rules 3-10, Intro(1)). It should be used
SunOS 5.11 Last change: 2 Nov 2007 2
User Commands getopts(1)
in place of the getopt command.
optstring must contain the option letters the command using
getopts recognizes. If a letter is followed by a colon, the
option is expected to have an argument, or group of argu-
ments, which must be separated from it by white space.
Each time it is invoked, getopts places the next option in
the shell variable name and the index of the next argument
to be processed in the shell variable OPTIND. Whenever the
shell or a shell script is invoked, OPTIND is initialized to
1.
When an option requires an option-argument, getopts places
it in the shell variable OPTARG.
If an illegal option is encountered, ? is placed in name.
When the end of options is encountered, getopts exits with a
non-zero exit status. The special option - can be used to
delimit the end of the options.
By default, getopts parses the positional parameters. If
extra arguments (argument ...) are specified on the getopts
command line, getopts parses them instead.
/usr/lib/getoptcvt reads the shell script in filename, con-
verts it to use getopts instead of getopt, and writes the
results on the standard output.
So that all new commands adhere to the command syntax stan-
dard described in Intro(1), they should use getopts or
getopt to parse positional parameters and check for options
that are valid for that command.
getopts prints an error message on the standard error when
it encounters an option letter not included in optstring.
Although the following command syntax rule (see Intro(1))
relaxations are permitted under the current implementation,
they should not be used because they can not be supported in
future releases of the system. As in the EXAMPLES section
SunOS 5.11 Last change: 2 Nov 2007 3
User Commands getopts(1)
below, -a and -b are options, and the option -o requires an
option-argument.
The following example violates Rule 5: options with option-
arguments must not be grouped with other options:
example% cmd -aboxxx filename
The following example violates Rule 6: there must be white
space after an option that takes an option-argument:
example% cmd -ab oxxx filename
Changing the value of the shell variable OPTIND or parsing
different sets of arguments can lead to unexpected results.
ksh
Checks arg for legal options. If arg is omitted, the posi-
tional parameters are used. An option argument begins with a
] or a -. An option not beginning with ] or - or the argu-
ment - ends the options. optstring contains the letters that
getopts recognizes. If a letter is followed by a :, that
option is expected to have an argument. The options can be
separated from the argument by blanks.
getopts places the next option letter it finds inside vari-
able name each time it is invoked with a ] prepended when
arg begins with a ]. The index of the next arg is stored in
OPTIND. The option argument, if any, gets stored in OPTARG.
A leading : in optstring causes getopts to store the letter
of an invalid option in OPTARG, and to set name to ? for an
unknown option and to : when a required option is missing.
Otherwise, getopts prints an error message. The exit status
is non-zero when there are no more options.
getopts supports both traditional single-character short
options and long options defined by Sun's Command Line
Interface Paradigm (CLIP).
SunOS 5.11 Last change: 2 Nov 2007 4
User Commands getopts(1)
Each long option is an alias for a short option and is
specified in parentheses following its equivalent short
option. For example, you can specify the long option file as
an alias for the short option f using the following script
line:
getopts "f(file)" opt
Precede long options on the command line with -- or ]. In
the example above, --file on the command line would be the
equivalent of -f, and ]file on the command line would be
the equivalent of ]f.
Each short option can have multiple long option equivalents,
although this is in violation of the CLIP specification and
should be used with caution. You must enclose each long
option equivalent parentheses, as follows:
getopts "f:(file)(input-file)o:(output-file)"
In the above example, both --file and --input-file are the
equivalent of -f, and --output-file is the equivalent of -o.
The variable name is always set to a short option. When a
long option is specified on the command line, name is set to
the short-option equivalent.
For a further discussion of the Korn shell's getopts built-
in command, see the previous discussion in the Bourne shell
(sh) section of this manpage.
ksh93
The getopts utility can be used to retrieve options and
arguments from a list of arguments specified by args or the
positional parameters if arg is omitted. It can also gen-
erate usage messages and a manual page for the command based
on the information in optstring.
Each time it is invoked, the getopts utility places the
value of the next option in the shell variable specified by
the name operand and the index of the next argument to be
processed in the shell variable OPTIND. When the shell is
SunOS 5.11 Last change: 2 Nov 2007 5
User Commands getopts(1)
invoked OPTIND is initialized to 1. When an option requires
or permits an option argument, getopts places the option
argument in the shell variable OPTARG. Otherwise OPTARG is
set to 1 when the option is set and 0 when the option is
unset.
The optstring string consists of alphanumeric characters,
the special characters ], -, ?, :, and SPACE or character
groups enclosed in [...]. Character groups can be nested in
{...}. Outside of a [...] group, a single NEWLINE followed
by zero or more blanks is ignored. One or more blank lines
separate the options from the command argument synopsis.
Each [...] group consists of an optional label, optional
attributes separated by :, and an optional description
string following ?. The characters from the ? to the end of
the next ] are ignored for option parsing and short usage
messages. They are used for generating verbose help or man
pages. The : character can not appear in the label. The ?
character must be specified as ?? in the label and the ]
character must be specified as ] in the description string.
Text between two \b (backspace) characters indicates that
the text should be emboldened when displayed. Text between
two \a (bell) characters indicates that the text should be
emphasized or italicized when displayed. Text between two \v
(vertical tab) characters indicates that the text should
displayed in a fixed-width font. Text between two \f (form
feed) characters is replaced by the output from the shell
function whose name is that of the enclosed text.
All output from this interface is written to the standard
error.
There are several group types:
1. A group of the form
[-[version][flag[number]...[?text]
which appears as the first group enables the
extended interface.
version specifies the interface version, currently
1. The latest version is assumed if version is
omitted. Future enhancements can increment version,
but all versions are supported. text typically
specifies an SCS or CVS identification string.
SunOS 5.11 Last change: 2 Nov 2007 6
User Commands getopts(1)
Zero or more flags with optional number values can
be specified to control option parsing. The flags
are:
Cache this optstring for multiple passes. Used to
optimize built-ins that can be called many times
within the same process.
i Ignore this optstring when generating help. Used
when combining optstring values from multiple
passes.
l Display only long option names in help messages.
o The - option character prefix is optional. This
supports the obsolete ps(1) option syntax.
p The number specifies the number of - characters
that must prefix long option names. The default is
2. 0, 1 or 2 are accepted, for example p0 for
dd(1M) and p1 for find(1).
s The number specifies the manual page section
number, 1 by default.
2. An option specification of the form
[option[!][=number][:longname][?text]. In this
case the first field is the option character, which
is the value returned in the name operand when the
option is matched. If there is no option character
then a two or more digit number should be speci-
fied. This number is returned as the value of the
name operand if the long option is matched. If
option is followed by a ! then the option character
sense is the inverse of the longname sense. For
options that do not take values OPTARG is set to 0
for ! inverted option characters and 1 otherwise.
=number optionally specifies a number to be
returned in the name operand instead of the option
character. A longname is specified by --longname
and is matched by the shortest non-ambiguous prefix
of all long options. An * in the longname field
indicates that only characters up to that point
need to match, provided any additional characters
match exactly. The enclosing [ and ] can be omitted
for an option that does not have a longname or
SunOS 5.11 Last change: 2 Nov 2007 7
User Commands getopts(1)
descriptive text.
3. An option argument specification. Options that take
arguments can be followed by :, indicating a string
value or #, indicating a numeric value, and an
option argument specification. An option argument
specification consists of the option argument name
as field 1. The remaining : separated fields are a
type name and zero or more of the special attribute
words listof, oneof, and ignorecase. A default
option value can be specified in the final field as
:=default. The option argument specification can be
followed by a list of option value descriptions
enclosed in braces. A long option that takes an
argument is specified as --longname=value. If the :
or # is followed by ?, the option argument is
optional. If only the option character form is
specified then the optional argument value is not
set if the next argument starts with - or ].
4. An option value description.
5. An argument specification. A list of valid option
argument values can be specified by enclosing them
inside a {...} following the option argument
specification. Each of the permitted values can be
specified with a [...] containing the value fol-
lowed by a description.
6. A group of the form []\n...] displays the charac-
ters representing ... in fixed-width font without
adding line breaks.
7. A group of the form []name?text] specifies a sec-
tion name with descriptive text. If name is omit-
ted, text is placed in a new paragraph.
8. A group of the form [-name?text] specifies entries
for the IMPLEMENTATION section.
If the leading character of optstring is ], arguments begin-
ning with ] are also be considered options.
A leading : character or a : following a leading ] in opt-
string affects the way errors are handled. If an option
character or longname argument not specified in optstring is
encountered when processing options, the shell variable
whose name is name is set to the ? character. The shell
variable OPTARG is set to the character found. If an option
argument is missing or has an invalid value, then name is
SunOS 5.11 Last change: 2 Nov 2007 8
User Commands getopts(1)
set to the : character and the shell variable OPTARG is set
to the option character found. Without the leading :, name
is set to the ? character, OPTARG is unset, and an error
message is written to standard error when errors are encoun-
tered.
The end of options occurs when:
1. The special argument -- is encountered.
2. An argument that does not begin with a - is encoun-
tered.
3. A help argument is specified.
4. An error is encountered.
If OPTIND is set to the value 1, a new set of arguments can
be used.
getopts can also be used to generate help messages contain-
ing command usage and detailed descriptions. Specify args
as:
-? Use this to generate a usage synopsis.
--?? Use this to generate a verbose usage message.
--??man Use this to generate a formatted manual page.
--??api Use this to generate an easy to parse usage
message.
--??html Use this to generate a man page in html format.
--??nroff Use this to generate a man page in nroff for-
mat.
--??usage Use this to list the current optstring.
--???name Use this to list version=n, where n is greater
than 0, if the option name is recognized by
SunOS 5.11 Last change: 2 Nov 2007 9
User Commands getopts(1)
getopts.
When the end of options is encountered, getopts exits with a
non-zero return value and the variable OPTIND is set to the
index of the first non-option argument.
OPTIONS
ksh93
The following options are supported by ksh93:
-a name Use name instead of the command name in usage
messages.
OPERANDS
The following operands are supported:
optstring A string containing the option characters
recognised by the utility invoking getopts. If
a character is followed by a colon, the option
is expected to have an argument, which should
be supplied as a separate argument. Applica-
tions should specify an option character and
its option-argument as separate arguments, but
getopts interprets the characters following an
option character requiring arguments as an
argument whether or not this is done. An expli-
cit null option-argument need not be recognised
if it is not supplied as a separate argument
when getopts is invoked; see getopt(3C). The
characters question-mark (?) and colon (:) must
not be used as option characters by an applica-
tion. The use of other option characters that
are not alphanumeric produces unspecified
results. If the option-argument is not supplied
as a separate argument from the option charac-
ter, the value in OPTARG is stripped of the
option character and the -. The first character
in optstring determines how getopts behaves if
an option character is not known or an option-
argument is missing.
name The name of a shell variable that is set by the
getopts utility to the option character that
was found.
SunOS 5.11 Last change: 2 Nov 2007 10
User Commands getopts(1)
The getopts utility by default parses positional parameters
passed to the invoking shell procedure. If args are speci-
fied, they are parsed instead of the positional parameters.
USAGE
Since getopts affects the current shell execution environ-
ment, it is generally provided as a shell regular built-in.
If it is called in a subshell or separate utility execution
environment, such as one of the following:
(getopts abc value "$@")
nohup getopts ...
find . -exec getopts ... \;
it does not affect the shell variables in the caller's
environment.
Notice that shell functions share OPTIND with the calling
shell even though the positional parameters are changed.
Functions that want to use getopts to parse their arguments
usually want to save the value of OPTIND on entry and
restore it before returning. However, there are cases when a
function wants to change OPTIND for the calling shell.
EXAMPLES
Example 1 Parsing and Displaying Arguments
The following example script parses and displays its argu-
ments:
aflag=
bflag=
while getopts ab: name
do
case $name in
a) aflag=1;;
b) bflag=1
bval="$OPTARG";;
?) printf "Usage: %s: [-a] [-b value] args\n" $0
exit 2;;
esac
done
if [ ! -z "$aflag" ]; then
printf "Option -a specified\n"
fi
if [ ! -z "$bflag" ]; then
printf 'Option -b "%s" specified\n' "$bval"
SunOS 5.11 Last change: 2 Nov 2007 11
User Commands getopts(1)
fi
shift $(($OPTIND - 1))
printf "Remaining arguments are: %s\n" "$*"
Example 2 Processing Arguments for a Command with Options
The following fragment of a shell program processes the
arguments for a command that can take the options -a or -b.
It also processes the option -o, which requires an option-
argument:
while getopts abo: c
do
case $c in
a b) FLAG=$c;;
o) OARG=$OPTARG;;
\?) echo $USAGE
exit 2;;
esac
done
shift `expr $OPTIND - 1`
Example 3 Equivalent Code Expressions
This code example accepts any of the following as
equivalent:
cmd -a -b -o "xxx z yy" filename
cmd -a -b -o "xxx z yy" -- filename
cmd -ab -o xxx,z,yy filename
cmd -ab -o "xxx z yy" filename
cmd -o xxx,z,yy -b -a filename
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of getopts: LANG,
LCAL, LCTYPE, LCMESAGES, and NLSPATH.
OPTIND This variable is used by getopts as the index of
the next argument to be processed.
OPTARG This variable is used by getopts to store the
argument if an option is using arguments.
SunOS 5.11 Last change: 2 Nov 2007 12
User Commands getopts(1)
EXIT STATUS
The following exit values are returned:
0 An option, specified or unspecified by optstring, was
found.
>0 The end of options was encountered or an error
occurred.
ksh93
The following exit values are returned by ksh93:
0 A specified option was found.
1 An end of options was encountered.
2 A usage or information message was generated.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/getopts, sh, ksh
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
Interface Stability Committed
Standard See standards(5).
ksh93
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
Interface Stability Uncommitted
SEE ALSO
Intro(1), getoptcvt(1), ksh(1), ksh93(1), ps(1), sh(1),
getopt(3C), attributes(5), environ(5), standards(5)
SunOS 5.11 Last change: 2 Nov 2007 13
User Commands getopts(1)
DIAGNOSTICS
Whenever an error is detected and the first character in the
optstring operand is not a colon (:), a diagnostic message
is written to standard error with the following information
in an unspecified format:
o The invoking program name is identified in the mes-
sage. The invoking program name is the value of the
shell special parameter 0 at the time the getopts
utility is invoked. A name equivalent to
basename "$0"
can be used.
o If an option is found that was not specified in
optstring, this error is identified and the invalid
option character is identified in the message.
o If an option requiring an option-argument is found,
but an option-argument is not found, this error is
identified and the invalid option character is
identified in the message.
SunOS 5.11 Last change: 2 Nov 2007 14
|
