wc.1

早期freebsd实现

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.\"     @(#)wc.1	8.2 (Berkeley) 4/19/94
.\"
.Dd April 19, 1994
.Dt WC 1
.Os
.Sh NAME
.Nm wc
.Nd word, line, and byte count
.Sh SYNOPSIS
.Nm wc
.Op Fl clw
.Op Ar file ...
.Sh DESCRIPTION
The
.Nm wc
utility displays the number of lines, words, and bytes contained in each
input
.Ar file
(or standard input, by default) to the standard output.
A line is defined as a string of characters delimited by a <newline>
character,
and a word is defined as a string of characters delimited by white space
characters.
White space characters are the set of characters for which the
.Xr isspace 3
function returns true.
If more than one input file is specified, a line of cumulative counts
for all the files is displayed on a separate line after the output for
the last file.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl c
The number of bytes in each input file
is written to the standard output.
.It Fl l
The number of lines in each input file
is written to the standard output.
.It Fl w
The number of words in each input file
is written to the standard output.
.El
.Pp
When an option is specified,
.Nm wc
only reports the information requested by that option.
The default action is equivalent to specifying all of the flags.
.Pp
If no files are specified, the standard input is used and no
file name is displayed.
.Pp
The
.Nm wc
utility exits 0 on success, and >0 if an error occurs.
.Sh SEE ALSO
.Xr isspace 3
.Sh COMPATIBILITY
Historically, the
.Nm wc
utility was documented to define a word as a ``maximal string of
characters delimited by <space>, <tab> or <newline> characters''.
The implementation, however, didn't handle non-printing characters
correctly so that ``  ^D^E  '' counted as 6 spaces, while ``foo^D^Ebar''
counted as 8 characters.
4BSD systems after 4.3BSD modified the implementation to be consistent
with the documentation.
This implementation defines a ``word'' in terms of the
.Xr isspace 3
function, as required by
.St -p1003.2 .
.Sh STANDARDS
The
.Nm wc
function conforms to
.St -p1003.2 .