linux 用grep匹配横线

file的内容如下：

ADSFADSFSDFASDFJKJK
----------------------------------------
ADSFADSFSDFASDFJKJK
----------------------------------------
ADSFADSFSDFASDFJKJK

linux 用grep匹配第2行和第4行横短线：

grep "^-*$" file

linux 用grep匹配不含横短线的行：
grep -v "^-*$" file


匹配多个字符串

grep 'string1\|string2' filename

grep -E "string1|string2" filename