What option counts only lines?

To count only the lines in a file, you can use the wc (word count) command with the -l option. This option counts the number of lines in the specified file. Here’s how to use it:

wc -l filename.txt

This command will output the number of lines in filename.txt. If you want to count lines from the output of another command, you can pipe it into wc -l. For example:

cat filename.txt | wc -l

This will also give you the count of lines in the file.