File: coreutils.info,  Node: wc invocation,  Next: sum invocation,  Up: Summarizing files

6.1 ‘wc’: Print newline, word, and byte counts
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‘wc’ counts the number of bytes, characters, words, and newlines in each
given FILE, or standard input if none are given or for a FILE of ‘-’.  A
word is a nonzero length sequence of printable characters delimited by
white space.  Synopsis:

     wc [OPTION]... [FILE]...

   ‘wc’ prints one line of counts for each file, and if the file was
given as an argument, it prints the file name following the counts.  By
default if more than one FILE is given, ‘wc’ prints a final line
containing the cumulative counts, with the file name ‘total’.  This
‘total’ line can be controlled with the ‘--total’ option, which is a GNU
extension.  The counts are printed in this order: newlines, words,
characters, bytes, maximum line length.  Each count is printed
right-justified in a field with at least one space between fields so
that the numbers and file names normally line up nicely in columns.  The
width of the count fields varies depending on the inputs, so you should
not depend on a particular field width.  However, as a GNU extension, if
only one count is printed, it is guaranteed to be printed without
leading spaces.

   By default, ‘wc’ prints three counts: the newline, words, and byte
counts.  Options can specify that only certain counts be printed.
Options do not undo others previously given, so

     wc --bytes --words

prints both the byte counts and the word counts.

   With the ‘--max-line-length’ option, ‘wc’ prints the length of the
longest line per file, and if there is more than one file it prints the
maximum (not the sum) of those lengths.  The line lengths here are
measured in screen columns, according to the current locale and assuming
tab positions in every 8th column.

   The program accepts the following options.  Also see *note Common
options::.

‘-c’
‘--bytes’
     Print only the byte counts.

‘-m’
‘--chars’
     Print only the character counts, as per the current locale.
     Invalid characters are not counted.

‘-w’
‘--words’
     Print only the word counts.  A word is a nonzero length sequence of
     printable characters separated by white space.

‘-l’
‘--lines’
     Print only the newline character counts.  Note a file without a
     trailing newline character, will not have that last portion
     included in the line count.

‘-L’
‘--max-line-length’
     Print only the maximum display widths.  Tabs are set at every 8th
     column.  Display widths of wide characters are considered.
     Non-printable characters are given 0 width.

‘--total=WHEN’
     Control when and how the final line with cumulative counts is
     printed.  WHEN is one of:
        • auto - This is the default mode of ‘wc’ when no ‘--total’
          option is specified.  Output a total line if more than one
          FILE is specified.
        • always - Always output a total line, irrespective of the
          number of files processed.
        • only - Only output total counts.  I.e., don’t print individual
          file counts, suppress any leading spaces, and don’t print the
          ‘total’ word itself, to simplify subsequent processing.
        • never - Never output a total line.

‘--files0-from=FILE’
     Disallow processing files named on the command line, and instead
     process those named in file FILE; each name being terminated by a
     zero byte (ASCII NUL). This is useful when the list of file names
     is so long that it may exceed a command line length limitation.  In
     such cases, running ‘wc’ via ‘xargs’ is undesirable because it
     splits the list into pieces and makes ‘wc’ print a total for each
     sublist rather than for the entire list.  One way to produce a list
     of ASCII NUL terminated file names is with GNU ‘find’, using its
     ‘-print0’ predicate.  If FILE is ‘-’ then the ASCII NUL terminated
     file names are read from standard input.

     For example, to find the length of the longest line in any ‘.c’ or
     ‘.h’ file in the current hierarchy, do this:

          find . -name '*.[ch]' -print0 |
            wc -L --files0-from=- | tail -n1

   An exit status of zero indicates success, and a nonzero value
indicates failure.