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OpenSolaris 2009.06 - man page for command (opensolaris section 1)

command(1)				  User Commands 			       command(1)

NAME
       command - execute a simple command

SYNOPSIS
   /usr/bin/command
       command [-p] command_name [argument]...

       command [-v | -V] command_name

   ksh93
       command [-pvxV] [command_name [argument...]]

DESCRIPTION
       The command utility causes the shell to treat the arguments as a simple command, suppress-
       ing the shell function lookup.

       If the command_name is the same as the name of one of the special built-in utilities,  the
       special	properties  do not occur. In every other respect, if command_name is not the name
       of a function, the effect of command (with no options) are the same as omitting command.

       The command utility also provides information concerning how a command name is interpreted
       by the shell. See -v and -V.

   ksh93
       Without	the  -v  or  -V option, command executes command_name with arguments specified by
       argument, suppressing the shell function lookup that normally occurs. In addition, if com-
       mand is a special built-in command, the special properties are removed so that failures do
       not cause the script that executes it to terminate.

       If the -v or -V options are specified, command is equivalent to whence(1).

OPTIONS
       The following options are supported by /usr/bin/command:

       -p    Performs the command search using a default value for PATH  that  is  guaranteed  to
	     find all of the standard utilities.

       -v    Writes  a	string	to  standard output that indicates the path or command that is be
	     used by the shell, in  the  current  shell  execution  environment  to  invoke  com-
	     mand_name, but does not invoke command_name.

		 o	Utilities,  regular  built-in  utilities, command_names including a slash
			character, and any implementation-provided functions that are found using
			the PATH variable is written as absolute path names.

		 o	Shell  functions,  special built-in utilities, regular built-in utilities
			not associated with a PATH search, and shell reserved words  are  written
			as just their names.

		 o	An  alias  is written as a command line that represents its alias defini-
			tion.

		 o	Otherwise, no output is written and the exit  status  reflects	that  the
			name was not found.

       -V    Writes a string to standard output that indicates how the name specified in the com-
	     mand_name operand is interpreted by the shell, in the current shell execution  envi-
	     ronment,  but  does  not  invoke command_name. Although the format of this string is
	     unspecified, it indicates in which of the following  categories  command_name  falls
	     and include the information stated:

		 o	Utilities,  regular  built-in  utilities, and any implementation-provided
			functions that are found using the PATH variable is  identified  as  such
			and include the absolute path name in the string.

		 o	Other shell functions is identified as functions.

		 o	Aliases  are  identified as aliases and their definitions are included in
			the string.

		 o	Special built-in utilities are identified as special built-in utilities.

		 o	Regular built-in utilities not associated with a PATH search  is  identi-
			fied as regular built-in utilities.

		 o	Shell reserved words are identified as reserved words.

   ksh93
       The following options are supported by ksh93 command:

       -p    Causes  a	default  path  to be searched rather than the one defined by the value of
	     PATH.

       -v    Equivalent to:

	       whence command [argument ...]

       -V    Equivalent to:

	       whence -v command [argument ...]

       -x    If command fails because there are too many arguments, it is invoked multiple  times
	     with a subset of the arguments on each invocation. Arguments that occur prior to the
	     first word that expand to multiple arguments and arguments that occur after the last
	     word that expands to multiple arguments are passed on each invocation. The exit sta-
	     tus is the maximum invocation exit status.

OPERANDS
       The following operands are supported:

       argument        One of the strings treated as an argument to command_name.

       command_name    The name of a utility or a special built-in utility.

EXAMPLES
       Example 1 Making a Version of cd That Always Prints Out the New Working Directory

       The following example takes a version of cd that always prints out the new working  direc-
       tory exactly once:

	 cd() {
	      command cd "$@" >/dev/null
	      pwd
	 }

       Example	2  Starting Off a secure shell script in Which the Script Avoids Being Spoofed by
       Its Parent

       The following example starts off a secure shell script in which the  script  avoids  being
       spoofed by its parent:

	 IFS='
	 '
	 #    The preceding value should be <space><tab><newline>.
	 #    Set IFS to its default value.
	 \unalias -a
	 #    Unset all possible aliases.
	 #    Note that unalias is escaped to prevent an alias
	 #    being used for unalias.
	 unset -f command
	 #    Ensure command is not a user function.
	 PATH="$(command -p getconf _CS_PATH):$PATH"
	 #    Put on a reliable PATH prefix.
	 #    ...

       At this point, given correct permissions on the directories called by PATH, the script has
       the ability to ensure that any utility it calls is the intended one. It is being very cau-
       tious  because  it  assumes that implementation extensions can be present that would allow
       user functions to exist when it is invoked. This capability is not specified by this docu-
       ment, but it is not prohibited as an extension. For example, the ENV variable precedes the
       invocation of the script with a user startup script. Such a script could define	functions
       to spoof the application.

ENVIRONMENT VARIABLES
       See  environ(5)	for  descriptions  of the following environment variables that affect the
       execution of command: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

       PATH    Determine the search path used during the  command  search,  except  as	described
	       under the -p option.

EXIT STATUS
   /usr/bin/command
       When the -v or -V options are specified, the following exit values are returned:

       0     Successful completion.

       >0    The command_name could not be found or an error occurred.

       Otherwise, the following exit values are returned:

       126    The utility specified by command_name was found but could not be invoked.

       127    An  error  occurred in the command utility or the utility specified by command_name
	      could not be found.

       Otherwise, the exit status of command is that of the simple command specified by the argu-
       ments to command.

   ksh93
       If command is invoked, the exit status of command is that of command. Otherwise, it is one
       of the following:

       0      command_name completed successfully.

       >0     -v or -V has been specified and an error occurred.

       126    command_name was found but could not be invoked.

       127    command_name could not be found.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

   /usr/bin/command
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

   ksh93
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Uncommitted		   |
       +-----------------------------+-----------------------------+

SEE ALSO
       ksh93(1), sh(1), type(1), whence(1), attributes(5), environ(5), standards(5)

SunOS 5.11				    8 Apr 2008				       command(1)


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