Regex

Question 1

Definition and Purpose of Regex

Answer 1

■ Regular expressions or regex is a specialized language and essential administrator tool used to describe and match patterns within text

■ Regex is not a command

■ Regex is a series of character-based structures that define patterns used for searching text

■ Regex allows rapid location of specific patterns in large amounts of text

■ Regex is useful for troubleshooting and incident response

■ Regex is used to filter command output and automate text processing tasks

Question 2

Wildcard character

Answer 2

. matches any single character

Question 3

. example

Answer 3

c.t matches cat cot or c-t

Question 4

\ character

Answer 4

treats the next character as a literal

Question 5

\ character example

Answer 5

cowa.bunga matches only cowa.bunga not cowaabunga or cowa-bunga

Question 6

^ anchor

Answer 6

anchors pattern to beginning of line

Question 7

^ example

Answer 7

^Hello matches lines beginning with Hello

Question 8

$ anchor

Answer 8

anchors pattern to end of line

Question 9

$ example

Answer 9

world$ matches lines ending with world

Question 10

[a-z]

Answer 10

matches any single lowercase letter a to z

Question 11

[0-9]

Answer 11

matches any single digit

Question 12

[a-z] example

Answer 12

ox matches fox box and pox

Question 13

?

Answer 13

matches zero or one occurrence of the preceding element

Question 14

*

Answer 14

matches zero or more occurrences of the preceding element

Question 15

+

Answer 15

matches one or more occurrences of the preceding element

Question 16

{n}

Answer 16

matches exactly n occurrences of the preceding element