The wc command computes the numbers of lines, words, and bytes in a file:
wc notes.txt
# > 3 7 35 /home/substack/notes.txt
Count words
wc -w notes.txt
# > 7 notes.txt
Count lines
wc -l notes.txt
3 notes.txt
Count bytes
wc -c notes.txt
# > 35 notes.txt
If you don't specify a file, wc will read from stdin. Type Ctrl+D (^D) to end the input.
wc -l
# > one
two
three
four
^D
4