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)