Best one-liner

Dave Burton

Judges' comments:

To use:

make

Try:

./prog < prog.c

Selected Judges Remarks:

A tiny, but punctually correct way of POSIX counting for text files. This one line, one word, 127 character beauty continues to expand the number of classic unix utilities available as winning entries.

Author’s comments:

Synopsis

Feed it anything on stdin.
The output should look familiar.

Compiles cleanly with:

WARN="-Wno-implicit-int -Wno-missing-variable-declarations -Wno-parentheses"
clang -Wall -Wextra -Weverything -pedantic $WARN -include stdio.h -o prog prog.c

Description

Included is a test script, useful for the corner cases. As in all good Unix programs, it is silent upon success; any output demonstrates an error. Instead of checking correctness, the check script can simply output the results:
(The Makefile contains the spoiler):

out=cat ./check ./prog

Interestingly, and a spoiler here: MacOS and FreeBSD implement the common utility “correctly”. Centos and Ubuntu both share a “flawed” utility that changes output format based upon input redirection or pipeline(!). As well, the latter two also behave slightly differently on what they count as whitespace: \a and \b are both counted whitespace(!), even though the relevant man pages on these systems omit these characters from the description.

This program follows FreeBSD and MacOS, the arbiters of correct for these purposes.

Limits

Requires the C locale and ASCII character set.
Input should be less than ten million octets toavoidthisproblem.

Bonus

The script cow provides a closer analog, and perhaps a more useful interface.

Included is a version without compilation warnings:

clang -Wall -Wextra -Weverything -pedantic -include stdio.h -o prog.clean prog.clean.c

Bugs

The flags are not supported. Although they could easily be added into cow. This exercise left to the reader.