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

     -v    Write a string to standard output that  indicates  the
           path or command that will be used by the shell, in the
           current  shell   execution   environment   to   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    Write 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  execu-
           tion  environment.  Although the format of this string
           is unspecified, it will indicate in which of the  fol-
           lowing  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: Make a version of cd that always prints  out  the
     new working directory exactly once:

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

     Example 2: Start 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 functions to exist when
     it  is  invoked.  This  capability  is not specified by this
     document, 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

     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  util-
           ity 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  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|
    | Interface Stability         | Standard                    |
    |_____________________________|_____________________________|

SEE ALSO

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