WHAT(1P)                   POSIX Programmer's Manual                  WHAT(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
       what -- identify SCCS files (DEVELOPMENT)

SYNOPSIS
       what [-s] file...

DESCRIPTION
       The what utility shall search the given files for all occurrences of
       the pattern that get (see get) substitutes for the %Z% keyword ("@(#)")
       and shall write to standard output what follows until the first
       occurrence of one of the following:


           "   >   newline   \   NUL

OPTIONS
       The what utility shall conform to the Base Definitions volume of
       POSIX.1-2017, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -s        Quit after finding the first occurrence of the pattern in
                 each file.

OPERANDS
       The following operands shall be supported:

       file      A pathname of a file to search.

STDIN
       Not used.

INPUT FILES
       The input files shall be of any file type.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of what:

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base Definitions
                 volume of POSIX.1-2017, Section 8.2, Internationalization
                 Variables 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 input
                 files).

       LC_MESSAGES
                 Determine the locale that should be used to affect the format
                 and contents of diagnostic messages written to standard
                 error.

       NLSPATH   Determine the location of message catalogs for the processing
                 of LC_MESSAGES.

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       The standard output shall consist of the following for each file
       operand:


           "%s:\n\t%s\n", <pathname>, <identification string>

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     Any matches were found.

       1     Otherwise.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       The what utility is intended to be used in conjunction with the SCCS
       command get, which automatically inserts identifying information, but
       it can also be used where the information is inserted by any other
       means.

       When the string "@(#)" is included in a library routine in a shared
       library, it might not be found in an a.out file using that library
       routine.

EXAMPLES
       If the C-language program in file f.c contains:


           char ident[] = "@(#)identification information";

       and f.c is compiled to yield f.o and a.out, then the command:


           what f.c f.o a.out

       writes:


           f.c:
               identification information
               ...
           f.o:
               identification information
               ...
           a.out:
               identification information
               ...

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       get

       The Base Definitions volume of POSIX.1-2017, Chapter 8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                  2017                             WHAT(1P)