Regular Expressions 101

Explanation

Pro

^start of string

Group 1(/dev/[\S]+|.*zroot\S*?)

1st Alternative/dev/[\S]+

/dev/the literal text /dev/ (case sensitive)

Character Class[\S]+

+matches at least one character from the set below:

\Sany character that is not Unicode whitespace

2nd Alternative.*zroot\S*?

.*any Unicode character (except for line terminators), repeated any number of times

zrootthe literal text zroot (case sensitive)

\S*?any character that is not Unicode whitespace, repeated any number of times

on the literal text on (case sensitive)

Group 2(/[\S]*)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

Character Class[\S]*

*matches any number of characters from the set below:

\Sany character that is not Unicode whitespace

the literal (32₁₀ / 40₈ / 20₁₆)

Positive Lookahead(?=(?:type)[\s]+([\S]+)|\(([^,]*))

1st Alternative(?:type)[\s]+([\S]+)

Non-Capturing Group(?:type)

typethe literal text type (case sensitive)

Character Class[\s]+

+matches at least one character from the set below:

\sa Unicode whitespace character

Group 3([\S]+)

Character Class[\S]+

+matches at least one character from the set below:

\Sany character that is not Unicode whitespace

2nd Alternative\(([^,]*)

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 4([^,]*)

Negated Character Class[^,]*

*matches any number of characters outside the set below:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

25 tokens

^(/dev/[\S]+|.*zroot\S*?) on (/[\S]*) (?=(?:type)[\s]+([\S]+)|\(([^,]*))

/dev/mapper/vg00-lv_root on / type ext4 (rw,errors=remount-ro)

/dev/mapper/vg00-lv_root on / type ext4 (rw,errors=remount-ro)