STANDARD INPUT

The standard input shall be used only if no file operands are specified. See Input Files.

INPUT FILES

The input files may be of any type.

ENVIRONMENT VARIABLES

The following environment variables shall affect the execution of wc:

LANG

This variable shall determine the locale to use for the locale categories when both LC_ALL and the corresponding environment variable (beginning with LC_ ) do not specify a locale. See 2.6.

LC_ALL

This variable shall determine the locale to be used to override any values for locale categories specified by the settings of LANG or any environment variables beginning with LC_.

LC_CTYPE

This variable shall determine the locale for the interpretation of sequences of bytes of text data as characters (e.g., single- versus multibyte characters in arguments and input files) and which characters are defined as ‘‘white space’’ characters.

LC_MESSAGES

This variable shall determine the language in which messages should be written.

ASYNCHRONOUS EVENTS

Default.

STANDARD OUTPUT

By default, the standard output shall contain a line for each input file of the form: "%d %d %d %s\n", <newlines>, <words>, <bytes>, <file> If any options are specified and the −l option is not specified, the number of <newline>s shall not be written.

If any options are specified and the −w option is not specified, the number of words shall not be written. If any options are specified and the −c option is not specified, the number of bytes shall not be written. If no input file operands are specified, no name shall be written and no <blank>s preceding the pathname shall be written. If more than one input file operand is specified, an additional line shall be written, of the same format as the other lines, except that the word total (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, shall be written at the end of the output.

STANDARD ERROR

Used only for diagnostic messages.

OUTPUT FILES

None.

EXAMPLES

None.

HISTORY OF DECISIONS MADE

The output file format pseudo- printf(3) string was derived from the HP-UX version of wc; the System V version: "%7d%7d%7d %s\n" produces possibly ambiguous and unparsable results for very large files, as it assumes no number will exceed six digits. Some historical implementations use only <space>, <tab>, and <newline> as word separators. The equivalent of the C Standard {7} isspace() function is more appropriate. The −c 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. Earlier drafts only specified the results when input files were text files. The current specification more closely matches existing practice. (Bytes, words, and <newline>s are counted separately and the results are written when an end-offile is detected.) Historical implementations of the wc utility only accepted one argument to specify the options −c, −l, and −w. Some of them also had multiple occurrences of an option cause the corresponding count to be output multiple times and having 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 standard should not break many existing applications (and does not break any historical portable applications.)