GETOPTCVT(1) User Commands GETOPTCVT(1)


NAME


getoptcvt - convert to getopts to parse command options

SYNOPSIS


/usr/lib/getoptcvt [-b] filename


/usr/lib/getoptcvt


DESCRIPTION


/usr/lib/getoptcvt reads the shell script in filename, converts it to use
getopts instead of getopt, and writes the results on the standard output.


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. (See the
NOTES section below.) The syntax for the shell's built-in getopts command
is:


getopts optstring name [ argument...]


optstring must contain the option letters the command using getopts will
recognize; 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, ? will be placed in name.


When the end of options is encountered, getopts exits with a non-zero
exit status. The special option -- may be used to delimit the end of the
options.


By default, getopts parses the positional parameters. If extra arguments
(argument ...) are given on the getopts command line, getopts parses them
instead.


So that all new commands will adhere to the command syntax standard
described in Intro(1), they should use getopts or getopt to parse
positional parameters and check for options that are valid for that
command (see the NOTES section below).

OPTIONS


The following option is supported:

-b
Makes the converted script portable to earlier releases of the UNIX
system. /usr/lib/getoptcvt modifies the shell script in filename
so that when the resulting shell script is executed, it determines
at run time whether to invoke getopts or getopt.


EXAMPLES


Example 1: Processing the arguments for a command




The following fragment of a shell program shows how one might process the
arguments for a command that can take the options -a or -b, as well as
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 2: Equivalent code expressions




This code 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(7) for descriptions of the following environment variables
that affect the execution of getopts: LC_CTYPE, LC_MESSAGES, and NLSPATH.

OPTIND
This variable is used by getoptcvt as the index of the next
argument to be processed.


OPTARG
This variable is used by getoptcvt to store the argument if an
option is using arguments.


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.


ATTRIBUTES


See attributes(7) for descriptions of the following attributes:


+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|CSI | enabled |
+---------------+-----------------+

SEE ALSO


Intro(1), getopts(1), sh(1), shell_builtins(1), getopt(3C), attributes(7)

DIAGNOSTICS


getopts prints an error message on the standard error when it encounters
an option letter not included in optstring.

NOTES


Although the following command syntax rule (see Intro(1)) relaxations are
permitted under the current implementation, they should not be used
because they may not be supported in future releases of the system. As in
the EXAMPLES section above, -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 may lead to unexpected results.


January 7, 2000 GETOPTCVT(1)