wc
[options] [files]Word count. Print a character, word, and line count for files. If multiple files, print totals as well. If no files are given, read standard input. See other examples under ls and sort.
-c
Print byte count only.
-C
Print character count only. This will be different than -c
in a multibyte character environment. Solaris only.
-l
Print line count only.
-m
Same as -C
. Solaris only.
-w
Print word count only.
Count the number of users logged in:
who | wc -l
Count the words in three essay files:
wc -w essay.[123]
Count lines in file named by $file
(don't display filename):
wc -l < $file