wc — count lines, words, and characters

What it does

wc (word count) reads input — a file or stdin — and reports how many lines, words, bytes, and characters it contains. By default it prints all three counts at once, in the order lines, words, bytes. Because it accepts a filename or reads from a pipe, it slots into almost any shell one-liner where you need a quick measurement.

Why it matters

wc is the universal measuring stick of the Unix text toolkit. It powers things like 'how many lines did this log have?', 'how many source files match this pattern?', and 'how many words is this document?' when piped after other commands. It is the natural partner of sort, uniq, and grep for turning raw text into concrete numbers.

Example

$ wc README.md

$ wc README.md\n  42  198 1320 README.md\n\n$ wc -l README.md\n42 README.md

$ grep -c 'error' server.log | wc -l

$ grep 'error' server.log | wc -l\n17

Common flags

-l

count newlines (lines) only

-w

count words only

-c

count bytes only (the raw size of the file)

-m

count characters instead of bytes (differs for multi-byte UTF-8)

-L

print the length of the longest line

-lw

combine flags — e.g. lines and words together