getopts(1) User Commands getopts(1)
getopts - parse utility options
/usr/bin/getopts optstring name [ arg...]
getopts optstring name [argument...]
getopts optstring name [arg...]
The getopts utility can be used to retrieve options and option-argu-
ments 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
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 stan-
dard error; otherwise, the shell variable OPTARG is unset and a diag-
nostic message is written to standard error. This condition is consid-
ered to be an error detected in the way arguments were presented to the
invoking application, but is not an error in getopts processing.
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 condi-
tion 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; a diagnostic 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 variable 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 spe-
cial 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 parameters or new arg val-
ues. 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
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 syntax standard (see Rules 3-10,
intro(1)). It should be used 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 arguments, 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
By default, getopts parses the positional parameters. If extra argu-
ments (argument ...) are given on the getopts command line, getopts
parses them instead.
/usr/lib/getoptcvt reads the shell script in filename, converts it to
use getopts instead of getopt, and writes the results on the standard
So that all new commands adhere to the command syntax standard
described in intro(1), they should use getopts or getopt to parse posi-
tional parameters and check for options that are valid for that com-
getopts prints an error message on the standard error when it encoun-
ters 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 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.
Checks arg for legal options. If arg is omitted, the positional parame-
ters are used. An option argument begins with a + or a -. An option not
beginning with + or - or the argument - 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 variable 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
getopts supports both traditional single-character short options and
long options defined by Sun's Command Line Interface Paradigm (CLIP).
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
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
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
The following operands are supported:
optstring A string containing the option characters recognised by
the utility invoking getopts. If a character is fol-
lowed by a colon, the option is expected to have an
argument, which should be supplied as a separate argu-
ment. Applications 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 explicit 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 application. The use of
other option characters that are not alphanumeric pro-
duces unspecified results. If the option-argument is
not supplied as a separate argument from the option
character, the value in OPTARG is stripped of the
option character and the -. The first character in opt-
string determines how getopts behaves if an option
character is not known or an option-argument is miss-
name The name of a shell variable that is set by the getopts
utility to the option character that was found.
The getopts utility by default parses positional parameters passed to
the invoking shell procedure. If args are given, they are parsed
instead of the positional parameters.
Since getopts affects the current shell execution environment, 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
(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.
Example 1: Parsing and Displaying Arguments
The following example script parses and displays its arguments:
while getopts ab: name
case $name in
?) printf "Usage: %s: [-a] [-b value] args\n" $0
if [ ! -z "$aflag" ]; then
printf "Option -a specified\n"
if [ ! -z "$bflag" ]; then
printf 'Option -b "%s" specified\n' "$bval"
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
case $c in
a | b) FLAG=$c;;
\?) echo $USAGE
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
See environ(5) for descriptions of the following environment variables
that affect the execution of getopts: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, 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.
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.
See attributes(5) for descriptions of the following attributes:
tab() allbox; cw(2.750000i)| cw(2.750000i) lw(2.750000i)|
lw(2.750000i). ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWcsu
intro(1), getoptcvt(1), ksh(1), sh(1), getopt(3C), attributes(5), envi-
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 message. The invok-
ing program name is the value of the shell special parameter 0 at
the time the getopts utility is invoked. A name equivalent to
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 5.10 21 Jul 2004 getopts(1)