Counting things

wc is short for word count, but it actually gives you three numbers at once.

Left to right: lines, words, bytes. Despite the name, words are only one of them.

You rarely want all three, so people normally narrow it down with an option.

• -l — lines
• -w — words
• -c — bytes (the c is from characters, but what it counts is bytes)

-l is the one you use most, because "how many of them are there" comes up all the time.

What -c counts is bytes, not characters. Usually they look the same, but put in a letter with an accent and they part company.

café is four letters. But é is not in the plain alphabet, and it takes two bytes, so café is five bytes. Add the newline and that is six.

When you want the number of characters, use -m.

wc can count things poured into it with |, without being given a file name at all.

When you do that, the file name on the right stops appearing, because what it counted had no name.

That is a small thing but a useful one. When all you want is the number, pouring it in gives you something you can use as it is.

This might be the commonest use of wc -l there is.

ls | wc -l tells you how many things are in there. ls puts out one name per line, and wc -l counts them.

All it saves you is counting with your eyes, but with a hundred of them that is quite a saving.

Hand it two or more files and a total line gets added after the individual numbers.

That is the shape for "how many lines are there in this whole directory".

Marking looks at whether the number is right, so do not miscount.

Though counting is wc's job. Yours is only to decide what it should count.