MAN(1P) - phpMan

MAN(1P)                    POSIX Programmer's Manual                   MAN(1P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       man - display system documentation
SYNOPSIS
       man [-k] name...
DESCRIPTION
       The man utility shall write information about each of  the  name  oper-
       ands. If name is the name of a standard utility, man at a minimum shall
       write a message describing the syntax used by the standard utility, its
       options,  and operands. If more information is available, the man util-
       ity shall provide it in an implementation-defined manner.
       An implementation may provide information for values of name other than
       the  standard utilities. Standard utilities that are listed as optional
       and that are not supported by the implementation either shall  cause  a
       brief  message  indicating  that  fact to be displayed or shall cause a
       full display of information as described previously.
OPTIONS
       The man utility  shall  conform  to  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
       The following option shall be supported:
       -k     Interpret  name  operands  as keywords to be used in searching a
              utilities summary database that contains a brief  purpose  entry
              for each standard utility and write lines from the summary data-
              base that match any of the keywords. The  keyword  search  shall
              produce  results  that  are  the equivalent of the output of the
              following command:

              grep -Ei 'name name...'  summary-database
       This assumes that the summary-database is a text  file  with  a  single
       entry per line; this organization is not required and the example using
       grep -Ei is merely illustrative of the type  of  search  intended.  The
       purpose  entry  to be included in the database shall consist of a terse
       description of the purpose of the utility.

OPERANDS
       The following operand shall be supported:
       name   A keyword or the name of a standard  utility.  When  -k  is  not
              specified and name does not represent one of the standard utili-
              ties, the results are unspecified.

STDIN
       Not used.
INPUT FILES
       None.
ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of man:
       LANG   Provide a default value for the  internationalization  variables
              that  are  unset  or  null.  (See the Base Definitions volume of
              IEEE Std 1003.1-2001, Section  8.2,  Internationalization  Vari-
              ables  for the precedence of internationalization variables used
              to determine the values of locale categories.)
       LC_ALL If set to a non-empty string value, override the values  of  all
              the other internationalization variables.
       LC_CTYPE
              Determine  the  locale  for  the  interpretation of sequences of
              bytes of text data as characters (for  example,  single-byte  as
              opposed to multi-byte characters in arguments and in the summary
              database).  The value of LC_CTYPE need not affect the format  of
              the information written about the name operands.
       LC_MESSAGES
              Determine  the  locale  that should be used to affect the format
              and contents of diagnostic messages written  to  standard  error
              and informative messages written to standard output.
       NLSPATH
              Determine the location of message catalogs for the processing of
              LC_MESSAGES .
       PAGER  Determine an output filtering command for writing the output  to
              a terminal. Any string acceptable as a command_string operand to
              the sh -c command shall be valid. When standard output is a ter-
              minal  device,  the reference page output shall be piped through
              the command.  If the PAGER variable is null or not set, the com-
              mand  shall  be  either  more or another paginator utility docu-
              mented in the system documentation.

ASYNCHRONOUS EVENTS
       Default.
STDOUT
       The man utility shall write text describing the syntax of  the  utility
       name,  its  options  and  its operands, or, when -k is specified, lines
       from the summary database. The format of this text  is  implementation-
       defined.
STDERR
       The standard error shall be used only for diagnostic messages.
OUTPUT FILES
       None.
EXTENDED DESCRIPTION
       None.
EXIT STATUS
       The following exit values shall be returned:
        0     Successful completion.
       >0     An error occurred.

CONSEQUENCES OF ERRORS
       Default.
       The following sections are informative.
APPLICATION USAGE
       None.
EXAMPLES
       None.
RATIONALE
       It  is recognized that the man utility is only of minimal usefulness as
       specified. The opinion of the standard developers was strongly  divided
       as to how much or how little information man should be required to pro-
       vide. They considered, however, that the provision of some portable way
       of  accessing  documentation  would aid user portability. The arguments
       against a fuller specification were:
        * Large quantities of documentation should not be required on a system
          that does not have excess disk space.
        * The  current  manual system does not present information in a manner
          that greatly aids user portability.
        * A "better help system" is currently an area in  which  vendors  feel
          that they can add value to their POSIX implementations.
       The -f option was considered, but due to implementation differences, it
       was not included in this volume of IEEE Std 1003.1-2001.
       The description was changed to be more specific about what  has  to  be
       displayed for a utility. The standard developers considered it insuffi-
       cient to allow a display of only the synopsis without  giving  a  short
       description of what each option and operand does.
       The  "purpose"  entry  to be included in the database can be similar to
       the section title  (less  the  numeric  prefix)  from  this  volume  of
       IEEE Std 1003.1-2001  for  each  utility.  These  titles are similar to
       those used in historical systems for this purpose.
       See mailx for rationale concerning the default paginator.
       The caveat in the LC_CTYPE description was added because it  is  not  a
       requirement  that  an implementation provide reference pages for all of
       its supported locales on each system; changing LC_CTYPE does not neces-
       sarily  translate  the  reference  page  into another language. This is
       equivalent    to    the    current    state    of    LC_MESSAGES     in
       IEEE Std 1003.1-2001-locale-specific  messages  are  not yet a require-
       ment.
       The historical MANPATH variable is not included  in  POSIX  because  no
       attempt is made to specify naming conventions for reference page files,
       nor even to mandate that they are files at all.   On  some  implementa-
       tions  they  could  be a true database, a hypertext file, or even fixed
       strings within the man executable.  The standard developers  considered
       the  portability  of reference pages to be outside their scope of work.
       However, users should be aware that MANPATH is implemented on a  number
       of historical systems and that it can be used to tailor the search pat-
       tern for reference pages from the various categories (utilities,  func-
       tions,  file  formats, and so on) when the system administrator reveals
       the location and conventions for reference pages on the system.
       The keyword search can rely on at least the text of the section  titles
       from  these  utility  descriptions, and the implementation may add more
       keywords. The term "section titles" refers to the strings such as:

              man - Display system documentation
              ps - Report process status
FUTURE DIRECTIONS
       None.
SEE ALSO
       more
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                              MAN(1P)