Topic 9 - Regular Expressions

Question 1

”.”

Answer 1

matches any single character except newline

Question 2

“*”

Answer 2

matches zero or more occurrence of the previous single character

Question 3

\ (backslash)

Answer 3

escape character

Question 4

^ (caret)

Answer 4

matches the beginning of a line

Question 5

$

Answer 5

matches the end of a line

do not use $ with double quotes - problems with the shell

Question 6

[…]

Answer 6

• matches a single character in a set or range of characters

- combine […] with * to match repeated sets

Question 7

[^…]

Answer 7

matches the complement of whats inside the square brackets

Question 8

\less-than-sign

Answer 8

matches the BEGINNING of a regular expression word

Question 9

>

Answer 9

matches the END of a regex word

Question 10

(….)

\n

Answer 10

• remembers a portion of regular expression

- recalls the remembered portion where n is a digit from 1 to 9

Question 11

X{m}

X{m,n}

Answer 11

• matches exactly m repeated of the one character regular expression X
• matches m to n repeats of X

Question 12

X{m,}

Answer 12

matches m or more repeats of X

Question 13

X{,m}

Answer 13

matches simply m or fewer repeats of X