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.TH WHAT "1P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH 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.
.\"
.SH NAME
what
\(em identify SCCS files (\fBDEVELOPMENT\fP)
.SH SYNOPSIS
.LP
.nf
what \fB[\fR-s\fB] \fIfile\fR...
.fi
.SH DESCRIPTION
The
.IR what
utility shall search the given files for all occurrences of the pattern
that
.IR get
(see
.IR "\fIget\fR\^")
substitutes for the %\fBZ\fP% keyword (\c
.BR \(dq@(#)\(dq )
and shall write to standard output what follows until the first
occurrence of one of the following:
.sp
.RS 4
.nf

\&"   >   newline   \e   NUL
.fi
.P
.RE
.SH OPTIONS
The
.IR what
utility shall conform to the Base Definitions volume of POSIX.1\(hy2017,
.IR "Section 12.2" ", " "Utility Syntax Guidelines".
.P
The following option shall be supported:
.IP "\fB\-s\fP" 10
Quit after finding the first occurrence of the pattern in each file.
.SH OPERANDS
The following operands shall be supported:
.IP "\fIfile\fR" 10
A pathname of a file to search.
.SH STDIN
Not used.
.SH "INPUT FILES"
The input files shall be of any file type.
.SH "ENVIRONMENT VARIABLES"
The following environment variables shall affect the execution of
.IR what :
.IP "\fILANG\fP" 10
Provide a default value for the internationalization variables that are
unset or null. (See the Base Definitions volume of POSIX.1\(hy2017,
.IR "Section 8.2" ", " "Internationalization Variables"
for the precedence of internationalization variables used to determine
the values of locale categories.)
.IP "\fILC_ALL\fP" 10
If set to a non-empty string value, override the values of all the
other internationalization variables.
.IP "\fILC_CTYPE\fP" 10
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).
.IP "\fILC_MESSAGES\fP" 10
.br
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard error.
.IP "\fINLSPATH\fP" 10
Determine the location of message catalogs for the processing of
.IR LC_MESSAGES .
.SH "ASYNCHRONOUS EVENTS"
Default.
.SH STDOUT
The standard output shall consist of the following for each
.IR file
operand:
.sp
.RS 4
.nf

"%s:\en\et%s\en", <\fIpathname\fR>, <\fIidentification string\fR>
.fi
.P
.RE
.SH STDERR
The standard error shall be used only for diagnostic messages.
.SH "OUTPUT FILES"
None.
.SH "EXTENDED DESCRIPTION"
None.
.SH "EXIT STATUS"
The following exit values shall be returned:
.IP 0 6
Any matches were found.
.IP 1 6
Otherwise.
.SH "CONSEQUENCES OF ERRORS"
Default.
.LP
.IR "The following sections are informative."
.SH "APPLICATION USAGE"
The
.IR what
utility is intended to be used in conjunction with the SCCS command
.IR get ,
which automatically inserts identifying information, but it can also be
used where the information is inserted by any other means.
.P
When the string
.BR \(dq@(#)\(dq 
is included in a library routine in a shared library, it might not be
found in an
.BR a.out
file using that library routine.
.SH EXAMPLES
If the C-language program in file
.BR f.c
contains:
.sp
.RS 4
.nf

char ident[] = "@(#)identification information";
.fi
.P
.RE
.P
and
.BR f.c
is compiled to yield
.BR f.o
and
.BR a.out ,
then the command:
.sp
.RS 4
.nf

what f.c f.o a.out
.fi
.P
.RE
.P
writes:
.sp
.RS 4
.nf

f.c:
    identification information
    ...
f.o:
    identification information
    ...
a.out:
    identification information
    ...
.fi
.P
.RE
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIget\fR\^"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "Chapter 8" ", " "Environment Variables",
.IR "Section 12.2" ", " "Utility Syntax Guidelines"
.\"
.SH 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 .
.PP
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 .