用'grep'匹配文件中的空行

Question

Why does

grep -c '^\n' myfile.txt

return 0 when there are empty lines in the file?

If there is an empty line, it starts with a new line, right?

Please correct me if I am wrong.

Answer 1

匹配行尾的正则表达式是$ ，而不是\\n （因为grep一次只处理一行，它会忽略行之间的换行符）。

grep -c '^$' myfile.txt

Answer 2

grep and count empty lines like this:

grep -c "^$" myfile.txt

As \\n is considered end of line you need to use line start and line end "^$"

Answer 3

The other answers with -c are correct.

If you want to see what number is the empty line in the file:

grep -n '^$' myfile.txt

For example:

grep -n '^$' /usr/share/wordlists/rockyou.txt
4751:
34329:
50383:
99361:
154363:
231236:
562997:
2459758:
14344383:
14344384:
14344385:

(If you want to remove them: sed -i '/^$/d' myfile.txt )

:)