grep 的常用元字元

^

Beginning-of-line anchor

'^love'

Matches all lines beginning with love.

$

End-of-line anchor

'love$'

Matches all lines ending with love.

.

Matches one character

'l..e'

Matches lines containing an l, followed by two characters, followed by an e.

*

Matches zero or more characters preceding the asterisk

' *love'

Matches lines with zero or more spaces, followed by the pattern love.

[ ]

Matches one character in the set

'[Ll]ove'

Matches lines containing love or Love.

[^]

Matches one character not in the set

'[^A–K]ove'

Matches lines not containing a character in the range A through K, followed by ove.

<

Beginning-of-word anchor

'

Matches lines containing a word that begins with love.

>

End-of-word anchor

'love>'

Matches lines containing a word that ends with love.

(..)

Tags matched characters

'(love)ing'

Tags marked portion in a register to be remembered later as number 1. To reference later, use 1 to repeat the pattern. May use up to nine tags, starting with the first tag at the leftmost part of the pattern. For example, the pattern love is saved in register 1 to be referenced later as 1.

x{m}

x{m,}

x{m,n}[a]

Repetition of character x: m times, at least m times, or between m and n times

'o{5}'

'o{5,}'

'o{5,10}'

Matches if line has 5 occurences of o, at least 5 occurences of o, or between 5 and 10 occurrences of