command(1)							   User Commands							command(1)

NAME

       command - execute a simple command

SYNOPSIS

       command [-p] command_name [argument...]

       command [-v | -V]  command_name

DESCRIPTION

       The command utility causes the shell to treat the arguments as a simple command, suppressing 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 will not occur. In every other
       respect, if command_name is not the name of a function, the effect of command (with no options) will be the same as omitting command.

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

OPTIONS

       The following options are supported:

       -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 will be used by the shell, in the current shell  execu-
		tion environment to invoke command_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 will be 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 will be written as just their names.

		  o  An alias will be written as a command line that represents its alias definition.

		  o  Otherwise, no output will be written and the exit status will reflect that the name was not found.

       -V	Writes a string to standard output that indicates how the name given in the command_name operand will be interpreted by the shell,
		in the current shell execution environment, but does not invoke command_name. Although the format of this string  is  unspecified,
		it will indicate 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  will
		     be identified as such and include the absolute path name in the string.

		  o  Other shell functions will be identified as functions.

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

		  o  Special built-in utilities will be identified as special built-in utilities.

		  o  Regular built-in utilities not associated with a PATH search will be identified as regular built-in utilities.

		  o  Shell reserved words will be identified as reserved words.

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 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

       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 cautious because it assumes that implementation extensions may be present that would allow user func-
       tions to exist when it is invoked. This capability is not specified by this document, but it is not prohibited as an extension.	For  exam-
       ple,  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

       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 will be that of the simple command specified by the arguments to command.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       sh(1), type(1), attributes(5), environ(5), standards(5)

SunOS 5.10							    17 Jul 2002 							command(1)