[unix-history] / usr.bin / getopt / getopt.1

.Dd June 21, 1993
.Dt GETOPT 1
.Os
.Sh NAME
.Nm getopt
.Nd parse command options
.Sh SYNOPSIS
.Nm set \-\- \`getopt optstring $*\`
.Sh DESCRIPTION
.Nm Getopt
is used to break up options in command lines for easy parsing by
shell procedures, and to check for legal options.
.Op Optstring
is a string of recognized option letters (see
.Xr getopt 3
);
if a letter is followed by a colon, the option
is expected to have an argument which may or may not be
separated from it by white space.
The special option
.B \-\-
is used to delimit the end of the options.
.Nm Getopt
will place
.B \-\-
in the arguments at the end of the options,
or recognize it if used explicitly.
The shell arguments
(\fB$1 $2\fR ...) are reset so that each option is
preceded by a
.B \-
and in its own shell argument;
each option argument is also in its own shell argument.
.Sh EXAMPLE
The following code fragment shows how one might process the arguments
for a command that can take the options
.Op a
and
.Op b ,
and the option
.Op o ,
which requires an argument.
.Pp
.Bd -literal -offset indent
set \-\- \`getopt abo: $*\`
if test $? != 0
then
	echo 'Usage: ...'
	exit 2
fi
for i
do
	case "$i"
	in
		\-a|\-b)
			flag=$i; shift;;
		\-o)
			oarg=$2; shift; shift;;
		\-\-)
			shift; break;;
	esac
done
.Ed
.Pp
This code will accept any of the following as equivalent:
.Pp
.Bd -literal -offset indent
cmd \-aoarg file file
cmd \-a \-o arg file file
cmd \-oarg -a file file
cmd \-a \-oarg \-\- file file
.Ed
.Sh SEE ALSO
.Xr sh 1 ,
.Xr getopt 3
.Sh DIAGNOSTICS
.Nm Getopt
prints an error message on the standard error output when it
encounters an option letter not included in
.Op optstring .
.Sh HISTORY
Written by Henry Spencer, working from a Bell Labs manual page.
Behavior believed identical to the Bell version.
.Sh BUGS
Whatever
.Xr getopt 3
has.
.Pp
Arguments containing white space or imbedded shell metacharacters
generally will not survive intact;  this looks easy to fix but isn't.
.Pp
The error message for an invalid option is identified as coming
from
.Nm getopt
rather than from the shell procedure containing the invocation
of
.Nm getopt ;
this again is hard to fix.
.Pp
The precise best way to use the
.Nm set
command to set the arguments without disrupting the value(s) of
shell options varies from one shell version to another.
Commit	Line	Data
7a2ca3d7 NW	1	.Dd June 21, 1993
	2	.Dt GETOPT 1
	3	.Os
	4	.Sh NAME
	5	.Nm getopt
	6	.Nd parse command options
	7	.Sh SYNOPSIS
	8	.Nm set \-\- \`getopt optstring $*\`
	9	.Sh DESCRIPTION
	10	.Nm Getopt
	11	is used to break up options in command lines for easy parsing by
	12	shell procedures, and to check for legal options.
	13	.Op Optstring
	14	is a string of recognized option letters (see
	15	.Xr getopt 3
	16	);
	17	if a letter is followed by a colon, the option
	18	is expected to have an argument which may or may not be
	19	separated from it by white space.
	20	The special option
	21	.B \-\-
	22	is used to delimit the end of the options.
	23	.Nm Getopt
	24	will place
	25	.B \-\-
	26	in the arguments at the end of the options,
	27	or recognize it if used explicitly.
	28	The shell arguments
	29	(\fB$1 $2\fR ...) are reset so that each option is
	30	preceded by a
	31	.B \-
	32	and in its own shell argument;
	33	each option argument is also in its own shell argument.
	34	.Sh EXAMPLE
	35	The following code fragment shows how one might process the arguments
	36	for a command that can take the options
	37	.Op a
	38	and
	39	.Op b ,
	40	and the option
	41	.Op o ,
	42	which requires an argument.
	43	.Pp
	44	.Bd -literal -offset indent
	45	set \-\- \`getopt abo: $*\`
	46	if test $? != 0
	47	then
	48	echo 'Usage: ...'
	49	exit 2
	50	fi
	51	for i
	52	do
	53	case "$i"
	54	in
	55	\-a\|\-b)
	56	flag=$i; shift;;
	57	\-o)
	58	oarg=$2; shift; shift;;
	59	\-\-)
	60	shift; break;;
	61	esac
	62	done
	63	.Ed
	64	.Pp
65	This code will accept any of the following as equivalent:
66	.Pp
67	.Bd -literal -offset indent
68	cmd \-aoarg file file
69	cmd \-a \-o arg file file
70	cmd \-oarg -a file file
71	cmd \-a \-oarg \-\- file file
72	.Ed
73	.Sh SEE ALSO
74	.Xr sh 1 ,
75	.Xr getopt 3
76	.Sh DIAGNOSTICS
77	.Nm Getopt
78	prints an error message on the standard error output when it
79	encounters an option letter not included in
80	.Op optstring .
81	.Sh HISTORY
82	Written by Henry Spencer, working from a Bell Labs manual page.
83	Behavior believed identical to the Bell version.
84	.Sh BUGS
85	Whatever
86	.Xr getopt 3
87	has.
88	.Pp
89	Arguments containing white space or imbedded shell metacharacters
90	generally will not survive intact; this looks easy to fix but isn't.
91	.Pp
92	The error message for an invalid option is identified as coming
93	from
94	.Nm getopt
95	rather than from the shell procedure containing the invocation
96	of
97	.Nm getopt ;
98	this again is hard to fix.
99	.Pp
100	The precise best way to use the
101	.Nm set
102	command to set the arguments without disrupting the value(s) of
103	shell options varies from one shell version to another.