[apple/system_cmds.git] / arch.tproj / arch.1

.\" Copyright (c) 1994 SigmaSoft, Th. Lockert
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"      This product includes software developed by SigmaSoft, Th. Lockert.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\"	$OpenBSD: arch.1,v 1.2 1996/06/29 20:29:34 tholo Exp $
.\"
.\" Modifications made 8/20/97 (c) Apple Computer, Inc.
.\" Modifications made 11/12/06 (c) Apple Computer, Inc.

.Dd July 8, 2010
.Dt ARCH 1
.Os "Mac OS X"
.Sh NAME
.Nm arch
.Nd print architecture type or run selected architecture of a universal binary
.Sh SYNOPSIS
.Nm arch
.Nm arch
.Op Fl 32
.Op Fl 64
.Oo
.Oo Fl Ns Ar arch_name | Fl arch Ar arch_name Oc Ns ...
.Oc
.Op Fl c
.Oo Fl d Ar envname Oc Ns ...
.Oo Fl e Ar envname=value Oc Ns ...
.Op Fl h
.Ar prog
.Op Ar args No ...
.Sh DESCRIPTION
The
.Nm arch
command with no arguments, displays the machine's architecture type.
.Pp
The other use of the
.Nm arch
command it to run a selected architecture of a universal binary.
A universal binary contains code that can run on different architectures.
By default, the operating system will select the architecture that most closely
matches the processor type.
This means that an intel architecture is selected on intel processors and a
powerpc architecture is selected on powerpc processors.
A 64-bit architecture is preferred over a 32-bit architecture on a 64-bit
processor, while only 32-bit architectures can run on a 32-bit processor.
.Pp
When the most natural architecture is unavailable, the operating system will
try to pick another architecture.
On 64-bit processors, a 32-bit architecture is tried.
If this is also unavailable, the operating system on an intel processor will
try running a 32-bit powerpc architecture.
Otherwise, no architecture is run, and an error results.
.Pp
The
.Nm arch
command can be used to alter the operating system's normal selection order.
The most common use is to select the 32-bit architecture on a 64-bit processor,
even if a 64-bit architecture is available.
.Pp
The
.Ar arch_name
argument must be one of the currently supported architectures:
.Bl -tag -width x86_64 -offset indent
.It i386
32-bit intel
.It x86_64
64-bit intel
.El
.Pp
Either prefix the architecture with a hyphen, or (for compatibility with
other commands), use
.Fl arch
followed by the architecture.
.Pp
If more than one architecture is specified, the operating system will try each
one in order, skipping an architecture that is not supported on the current
processor, or is unavailable in the universal binary.
.Pp
The other options are:
.Bl -tag -width ".Fl e Ar envname=value"
.It Fl 32
Add the native 32-bit architecture to the list of architectures.
.It Fl 64
Add the native 64-bit architecture to the list of architectures.
.It Fl c
Clears the environment that will be passed to the command to be run.
.It Fl d Ar envname
Deletes the named environment variable from the environment that will be passed
to the command to be run.
.It Fl e Ar envname=value
Assigns the given value to the named environment variable in the environment
that will be passed to the command to be run.
Any existing environment variable with the same name will be replaced.
.It Fl h
Prints a usage message and exits.
.El
.Pp
The
.Ar prog
argument is the command to run, followed by any arguments to pass to the
command.
It can be a full or partial path, while a lone name will be looked up in the user's
command search path.
.Pp
If no architectures are specified on the command line, the
.Nm arch
command takes the basename of the
.Ar prog
argument and searches for the first property list file with that basename and
the
.Pa \&.plist
suffix, in the
.Pa archSettings
sub-directory in each of the standard domains, in the following order:
.Bl -tag -width ".Pa /Network/Library/archSettings" -offset indent
.It ~/Library/archSettings
User settings
.It /Library/archSettings
Local settings
.It /Network/Library/archSettings
Network settings
.It /System/Library/archSettings
System settings
.El
.Pp
This property list contains the architecture order preferences, as well
as the full path to the real executable.
For examples of the property list format, look at the files in
.Pa /System/Library/archSettings .
.Ss Example
On an intel processor:
.Bd -literal -offset indent
% perl -MConfig -e 'printf "%s\\n", $Config{byteorder}'
1234
.Ed
.Pp
shows the intel little endian byte order.
.Ss Making links to the arch command
When a link is made to
.Nm arch
command with a different name, that name is used to find
the corresponding property list file.
Thus, other commands can be wrapped so that they have custom architecture
selection order.
.Pp
Because of some internal logic in the code, hard links to the
.Nm arch
command may not work quite right.
It is best to avoid using hard links, and only use symbolic links to the
.Nm arch
command.
.Ss Environment
The environment variable
.Ev ARCHPREFERENCE
can be used to provide architecture order preferences.
It is checked before looking for the corresponding property list file.
.Pp
The value of the environment variable
.Ev ARCHPREFERENCE
is composed of one or more specifiers, separated by semicolons.
A specifier is made up of one, two or three fields, separated by colons.
Architectures specified in order, are separated by commas and make up the last
(mandatory) field.
The first field, if specified, is a name of a program, which selects this
specifier if that name matches the program name in question.
If the name field is empty or there is no name field, the specifier matches
any program name.
Thus, ordering of specifiers is important, and the one with no name should
be last.
.Pp
When the
.Nm arch
command is called directly, the
.Ar prog
name provides the path information to the executable (possibly via the command
search path).
When a name is specified in a
.Ev ARCHPREFERENCE
specifier, the path information can alternately be specified as a second
field following the name.
When the
.Nm arch
command is called indirectly via a link, this path information must be
specified.
If not specified as a second field in a specifier, the executable path will
be looked up in the corresponding property list file.
.Ss Example ARCHPREFERENCE Values
.Bl -tag -width "    "
.It i386,x86_64
A specifier that matches any name.
.It foo:i386,x86_64
A specifier that matches the program named
.Nm foo
(the full executable path is in the
.Pa foo.plist
file).
.It foo:/op/bin/boo:i386,x86_64
A specifier with all fields specified.
.It baz:i386;x86_64
A specifier for
.Nm baz
and a second specifier that would match any other name.
.El
.Sh BUGS
Running the
.Nm arch
command on an interpreter script may not work if the interpreter is a link
to the arch command, especially if a 64-bit architecture is specified (since the
.Nm arch
command is 2-way universal, 32-bit only).
.Sh SEE ALSO
.Xr machine 1
Commit	Line	Data
b51d5b5f A	1	.\" Copyright (c) 1994 SigmaSoft, Th. Lockert
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by SigmaSoft, Th. Lockert.
	15	.\" 4. The name of the author may not be used to endorse or promote products
	16	.\" derived from this software without specific prior written permission
	17	.\"
	18	.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	19	.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	20	.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	21	.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	22	.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	23	.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	24	.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	25	.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	26	.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	27	.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	28	.\"
	29	.\" $OpenBSD: arch.1,v 1.2 1996/06/29 20:29:34 tholo Exp $
	30	.\"
	31	.\" Modifications made 8/20/97 (c) Apple Computer, Inc.
34d340d7	32	.\" Modifications made 11/12/06 (c) Apple Computer, Inc.
b51d5b5f	33
8459d725	34	.Dd July 8, 2010
b51d5b5f	35	.Dt ARCH 1
34d340d7	36	.Os "Mac OS X"
b51d5b5f A	37	.Sh NAME
b51d5b5f A	38	.Nm arch
34d340d7	39	.Nd print architecture type or run selected architecture of a universal binary
b51d5b5f A	40	.Sh SYNOPSIS
b51d5b5f A	41	.Nm arch
34d340d7	42	.Nm arch
8459d725 A	43	.Op Fl 32
8459d725 A	44	.Op Fl 64
34d340d7 A	45	.Oo
	46	.Oo Fl Ns Ar arch_name \| Fl arch Ar arch_name Oc Ns ...
	47	.Oc
8459d725 A	48	.Op Fl c
	49	.Oo Fl d Ar envname Oc Ns ...
	50	.Oo Fl e Ar envname=value Oc Ns ...
	51	.Op Fl h
34d340d7 A	52	.Ar prog
34d340d7 A	53	.Op Ar args No ...
b51d5b5f A	54	.Sh DESCRIPTION
	55	The
	56	.Nm arch
34d340d7 A	57	command with no arguments, displays the machine's architecture type.
	58	.Pp
	59	The other use of the
	60	.Nm arch
	61	command it to run a selected architecture of a universal binary.
	62	A universal binary contains code that can run on different architectures.
	63	By default, the operating system will select the architecture that most closely
	64	matches the processor type.
	65	This means that an intel architecture is selected on intel processors and a
	66	powerpc architecture is selected on powerpc processors.
ef8ad44b	67	A 64-bit architecture is preferred over a 32-bit architecture on a 64-bit
34d340d7 A	68	processor, while only 32-bit architectures can run on a 32-bit processor.
	69	.Pp
	70	When the most natural architecture is unavailable, the operating system will
	71	try to pick another architecture.
	72	On 64-bit processors, a 32-bit architecture is tried.
	73	If this is also unavailable, the operating system on an intel processor will
	74	try running a 32-bit powerpc architecture.
	75	Otherwise, no architecture is run, and an error results.
	76	.Pp
	77	The
	78	.Nm arch
ef8ad44b	79	command can be used to alter the operating system's normal selection order.
34d340d7 A	80	The most common use is to select the 32-bit architecture on a 64-bit processor,
	81	even if a 64-bit architecture is available.
	82	.Pp
	83	The
34d340d7 A	84	.Ar arch_name
	85	argument must be one of the currently supported architectures:
	86	.Bl -tag -width x86_64 -offset indent
	87	.It i386
	88	32-bit intel
34d340d7 A	89	.It x86_64
	90	64-bit intel
	91	.El
	92	.Pp
	93	Either prefix the architecture with a hyphen, or (for compatibility with
	94	other commands), use
	95	.Fl arch
	96	followed by the architecture.
	97	.Pp
	98	If more than one architecture is specified, the operating system will try each
	99	one in order, skipping an architecture that is not supported on the current
	100	processor, or is unavailable in the universal binary.
	101	.Pp
8459d725 A	102	The other options are:
	103	.Bl -tag -width ".Fl e Ar envname=value"
	104	.It Fl 32
	105	Add the native 32-bit architecture to the list of architectures.
	106	.It Fl 64
	107	Add the native 64-bit architecture to the list of architectures.
	108	.It Fl c
	109	Clears the environment that will be passed to the command to be run.
	110	.It Fl d Ar envname
	111	Deletes the named environment variable from the environment that will be passed
	112	to the command to be run.
	113	.It Fl e Ar envname=value
	114	Assigns the given value to the named environment variable in the environment
	115	that will be passed to the command to be run.
	116	Any existing environment variable with the same name will be replaced.
	117	.It Fl h
	118	Prints a usage message and exits.
	119	.El
	120	.Pp
34d340d7 A	121	The
	122	.Ar prog
	123	argument is the command to run, followed by any arguments to pass to the
	124	command.
ef8ad44b	125	It can be a full or partial path, while a lone name will be looked up in the user's
34d340d7 A	126	command search path.
	127	.Pp
	128	If no architectures are specified on the command line, the
	129	.Nm arch
	130	command takes the basename of the
	131	.Ar prog
	132	argument and searches for the first property list file with that basename and
	133	the
	134	.Pa \&.plist
	135	suffix, in the
	136	.Pa archSettings
	137	sub-directory in each of the standard domains, in the following order:
	138	.Bl -tag -width ".Pa /Network/Library/archSettings" -offset indent
	139	.It ~/Library/archSettings
	140	User settings
	141	.It /Library/archSettings
	142	Local settings
	143	.It /Network/Library/archSettings
	144	Network settings
	145	.It /System/Library/archSettings
	146	System settings
	147	.El
	148	.Pp
	149	This property list contains the architecture order preferences, as well
	150	as the full path to the real executable.
	151	For examples of the property list format, look at the files in
	152	.Pa /System/Library/archSettings .
	153	.Ss Example
	154	On an intel processor:
	155	.Bd -literal -offset indent
	156	% perl -MConfig -e 'printf "%s\\n", $Config{byteorder}'
	157	1234
	158	.Ed
	159	.Pp
8459d725	160	shows the intel little endian byte order.
34d340d7 A	161	.Ss Making links to the arch command
	162	When a link is made to
	163	.Nm arch
	164	command with a different name, that name is used to find
	165	the corresponding property list file.
	166	Thus, other commands can be wrapped so that they have custom architecture
	167	selection order.
	168	.Pp
	169	Because of some internal logic in the code, hard links to the
	170	.Nm arch
	171	command may not work quite right.
	172	It is best to avoid using hard links, and only use symbolic links to the
	173	.Nm arch
	174	command.
	175	.Ss Environment
	176	The environment variable
	177	.Ev ARCHPREFERENCE
	178	can be used to provide architecture order preferences.
	179	It is checked before looking for the corresponding property list file.
	180	.Pp
	181	The value of the environment variable
	182	.Ev ARCHPREFERENCE
	183	is composed of one or more specifiers, separated by semicolons.
	184	A specifier is made up of one, two or three fields, separated by colons.
	185	Architectures specified in order, are separated by commas and make up the last
	186	(mandatory) field.
	187	The first field, if specified, is a name of a program, which selects this
	188	specifier if that name matches the program name in question.
	189	If the name field is empty or there is no name field, the specifier matches
	190	any program name.
	191	Thus, ordering of specifiers is important, and the one with no name should
	192	be last.
	193	.Pp
	194	When the
	195	.Nm arch
	196	command is called directly, the
	197	.Ar prog
	198	name provides the path information to the executable (possibly via the command
	199	search path).
	200	When a name is specified in a
	201	.Ev ARCHPREFERENCE
	202	specifier, the path information can alternately be specified as a second
	203	field following the name.
	204	When the
	205	.Nm arch
	206	command is called indirectly via a link, this path information must be
	207	specified.
	208	If not specified as a second field in a specifier, the executable path will
	209	be looked up in the corresponding property list file.
	210	.Ss Example ARCHPREFERENCE Values
	211	.Bl -tag -width " "
8459d725	212	.It i386,x86_64
34d340d7	213	A specifier that matches any name.
8459d725	214	.It foo:i386,x86_64
34d340d7 A	215	A specifier that matches the program named
	216	.Nm foo
	217	(the full executable path is in the
	218	.Pa foo.plist
	219	file).
8459d725	220	.It foo:/op/bin/boo:i386,x86_64
34d340d7	221	A specifier with all fields specified.
8459d725	222	.It baz:i386;x86_64
34d340d7 A	223	A specifier for
	224	.Nm baz
	225	and a second specifier that would match any other name.
	226	.El
	227	.Sh BUGS
	228	Running the
	229	.Nm arch
	230	command on an interpreter script may not work if the interpreter is a link
	231	to the arch command, especially if a 64-bit architecture is specified (since the
	232	.Nm arch
	233	command is 2-way universal, 32-bit only).
b51d5b5f A	234	.Sh SEE ALSO
b51d5b5f A	235	.Xr machine 1