man-pages/man1p/wc.1p

.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "WC" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" wc 
.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
wc \- word, line, and byte or character count
.SH SYNOPSIS
.LP
\fBwc\fP \fB[\fP\fB-c|-m\fP\fB][\fP\fB-lw\fP\fB][\fP\fIfile\fP\fB...\fP\fB]\fP
.SH DESCRIPTION
.LP
The \fIwc\fP utility shall read one or more input files and, by default,
write the number of <newline>s, words, and bytes
contained in each input file to the standard output.
.LP
The utility also shall write a total count for all named files, if
more than one input file is specified.
.LP
The \fIwc\fP utility shall consider a \fIword\fP to be a non-zero-length
string of characters delimited by white space.
.SH OPTIONS
.LP
The \fIwc\fP utility shall conform to the Base Definitions volume
of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
.LP
The following options shall be supported:
.TP 7
\fB-c\fP
Write to the standard output the number of bytes in each input file.
.TP 7
\fB-l\fP
Write to the standard output the number of <newline>s in each input
file.
.TP 7
\fB-m\fP
Write to the standard output the number of characters in each input
file.
.TP 7
\fB-w\fP
Write to the standard output the number of words in each input file.
.sp
.LP
When any option is specified, \fIwc\fP shall report only the information
requested by the specified options.
.SH OPERANDS
.LP
The following operand shall be supported:
.TP 7
\fIfile\fP
A pathname of an input file. If no \fIfile\fP operands are specified,
the standard input shall be used.
.sp
.SH STDIN
.LP
The standard input shall be used only if no \fIfile\fP operands are
specified. See the INPUT FILES section.
.SH INPUT FILES
.LP
The input files may be of any type.
.SH ENVIRONMENT VARIABLES
.LP
The following environment variables shall affect the execution of
\fIwc\fP:
.TP 7
\fILANG\fP
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 Variables
for
the precedence of internationalization variables used to determine
the values of locale categories.)
.TP 7
\fILC_ALL\fP
If set to a non-empty string value, override the values of all the
other internationalization variables.
.TP 7
\fILC_CTYPE\fP
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) and
which characters are defined as white space characters.
.TP 7
\fILC_MESSAGES\fP
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.
.TP 7
\fINLSPATH\fP
Determine the location of message catalogs for the processing of \fILC_MESSAGES
\&.\fP 
.sp
.SH ASYNCHRONOUS EVENTS
.LP
Default.
.SH STDOUT
.LP
By default, the standard output shall contain an entry for each input
file of the form:
.sp
.RS
.nf

\fB"%d %d %d %s\\n", <\fP\fInewlines\fP\fB>, <\fP\fIwords\fP\fB>, <\fP\fIbytes\fP\fB>, <\fP\fIfile\fP\fB>
\fP
.fi
.RE
.LP
If the \fB-m\fP option is specified, the number of characters shall
replace the <\fIbytes\fP> field in this format.
.LP
If any options are specified and the \fB-l\fP option is not specified,
the number of <newline>s shall not be written.
.LP
If any options are specified and the \fB-w\fP option is not specified,
the number of words shall not be written.
.LP
If any options are specified and neither \fB-c\fP nor \fB-m\fP is
specified, the number of bytes or characters shall not be
written.
.LP
If no input \fIfile\fP operands are specified, no name shall be written
and no <blank>s preceding the pathname shall be
written.
.LP
If more than one input \fIfile\fP operand is specified, an additional
line shall be written, of the same format as the other
lines, except that the word \fBtotal\fP (in the POSIX locale) shall
be written instead of a pathname and the total of each column
shall be written as appropriate. Such an additional line, if any,
is written at the end of the output.
.SH STDERR
.LP
The standard error shall be used only for diagnostic messages.
.SH OUTPUT FILES
.LP
None.
.SH EXTENDED DESCRIPTION
.LP
None.
.SH EXIT STATUS
.LP
The following exit values shall be returned:
.TP 7
\ 0
Successful completion.
.TP 7
>0
An error occurred.
.sp
.SH CONSEQUENCES OF ERRORS
.LP
Default.
.LP
\fIThe following sections are informative.\fP
.SH APPLICATION USAGE
.LP
The \fB-m\fP option is not a switch, but an option at the same level
as \fB-c\fP. Thus, to produce the full default output
with character counts instead of bytes, the command required is:
.sp
.RS
.nf

\fBwc -mlw
\fP
.fi
.RE
.SH EXAMPLES
.LP
None.
.SH RATIONALE
.LP
The output file format pseudo- \fIprintf\fP() string differs from
the System V version
of \fIwc\fP:
.sp
.RS
.nf

\fB"%7d%7d%7d %s\\n"
\fP
.fi
.RE
.LP
which produces possibly ambiguous and unparsable results for very
large files, as it assumes no number shall exceed six
digits.
.LP
Some historical implementations use only <space>, <tab>, and <newline>
as word separators. The equivalent of
the ISO\ C standard \fIisspace\fP() function is more appropriate.
.LP
The \fB-c\fP option stands for "character" count, even though it counts
bytes. This stems from the sometimes erroneous
historical view that bytes and characters are the same size. Due to
international requirements, the \fB-m\fP option (reminiscent
of "multi-byte") was added to obtain actual character counts.
.LP
Early proposals only specified the results when input files were text
files. The current specification more closely matches
historical practice. (Bytes, words, and <newline>s are counted separately
and the results are written when an end-of-file is
detected.)
.LP
Historical implementations of the \fIwc\fP utility only accepted one
argument to specify the options \fB-c\fP, \fB-l\fP, and
\fB-w\fP. Some of them also had multiple occurrences of an option
cause the corresponding count to be written multiple times and
had the order of specification of the options affect the order of
the fields on output, but did not document either of these.
Because common usage either specifies no options or only one option,
and because none of this was documented, the changes required
by this volume of IEEE\ Std\ 1003.1-2001 should not break many historical
applications (and do not break any historical
conforming applications).
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIcksum\fP
.SH 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 .