grep

Question 1

grep

Answer 1

displays lines in a file or stream that match a pattern expressed as a regular expression

Question 2

grep command syntax

Answer 2

grep options ‘regular expression’ file(s)

Question 3

-i

Answer 3

ignores case for matching

Question 4

-v

Answer 4

Doesn’t display lines matching expression

Question 5

-n

Answer 5

Displays line and n lines after matching lines (linux)

Question 6

-c

Answer 6

Displays count of number of occurrences

Question 7

-l

Answer 7

Displays list of filenames only

Question 8

-e exp

Answer 8

Specifies given expression and can use multiple times

Question 9

-x

Answer 9

Matches pattern with entire line (doesn’t match embedded patterns)

Question 10

-f file

Answer 10

Takes pattern from file, one per line

Question 11

-E or egrep

Answer 11

Treats pattern as an extended regular expression (ERE)

Question 12

-F

Answer 12

Matches multiple fixed strings (in fgrep-style)

Question 13

-A n

Answer 13

Display line and n lines after matching lines (linux)

Question 14

-B n

Answer 14

Display line and n lines before matching line (linux)

Answer 15

matches a pattern at the beginning of a line

Question 16

The caret has a triple role to play in regular expressions. When placed at the beginning of a character class (e.g., [^a-z]), it _____ every character of the class. When placed outside it, and at the beginning of the expression (e.g., ^2…), the pattern is matched at the ____ of the line. At any other location (e.g., a^b), it matches ____ literally.

Answer 16

The caret has a triple role to play in regular expressions. When placed at the beginning of a character class (e.g., [^a-z]), it negates every character of the class. When placed outside it, and at the beginning of the expression (e.g., ^2…), the pattern is matched at the beginning of the line. At any other location (e.g., a^b), it matches itself literally.

Question 17

grep special character (for making Basic Regular Expressions)

The end of a line

Answer 17

$

Question 18

*

Answer 18

zero or more occurrences of the previous character

Question 19

grep special character

(for making Basic Regular Expressions)

a single character that is one of the ones listed in

Answer 19

[ ]

a single character that is one of the ones listed in
[ … ].

(similar to [ … ] for shell
file matching)

Question 20

.

Answer 20

Matches single character

Question 21

[abc]

Answer 21

a single character a, b, c

Question 22

[c1-c2]

Answer 22

A single character with the ASCII range represented by c1 and c2

Question 23

[^abc]

Answer 23

A single character that is not a, b, or

Question 24

^pat

Answer 24

Pattern pat at the beginning of a line

Question 25

pat$

Answer 25

Pattern pat at the end of line

Question 26

-F

Answer 26

Matches multiple fixed strings (in fgrep-style)

Question 27

A regular expression uses an elaborate metacharacter set that overshadows the shell’s ____ _____.

Answer 27

A regular expression uses an elaborate metacharacter set that overshadows the shell’s wild cards.

Question 28

Define: A regular expression

Answer 28

A regular expression uses an elaborate metacharacter set that overshadows the shell’s wild cards. grep uses this expression to match multiple similar patterns

Question 29

Unlike wild cards, however, a regular expression is a feature of the _____ that uses it and has nothing to do with the _____. Quoting ensures that the _____ isn’t able to interfere and interpret the metacharacters in its own way.

Answer 29

Regular expressions are interpreted by the command and not by the shell. Quoting ensures that the shell isn’t able to interfere and interpret the meta-characters in its own way.

Question 30

How does the command interpret the the following BRE: g*

Answer 30

Nothing or g, gg, ggg, etc

Question 31

How does the command interpret the the following BRE: gg*

Answer 31

g, gg, ggg, etc

Question 32

How does the command interpret the the following BRE: .*

Answer 32

Any number of characters, or none

Question 33

How does the command interpret the the following BRE: [1-3]

Answer 33

A digit between 1 and 3

Question 34

How does the command interpret the the following BRE: [^a-zA-Z]

Answer 34

A non alphanumeric character

Question 35

How does the command interpret the the following BRE: bash$

Answer 35

bash at the end of a line

Question 36

How does the command interpret the the following BRE: ^bash$

Answer 36

bash as the only word in line

Question 37

How does the command interpret the the following BRE: ^$

Answer 37

Lines containing nothing

Question 38

Define: a character class

Answer 38

A regular expression lets you specify a group of characters enclosed within a pair of rectangular brackets, [ ]. The match is then performed for any single character in the group. This form resembles the one used by the shell’s wild cards.

Question 39

match a string beginning with e

Answer 39

ee*

Question 40

How do you match trueman and truman from emp.1st

Answer 40

grep “true*man” emp.lst

Question 41

How do you match match wilcocks and wilcox from emp.1st

Answer 41

grep “wilco[cx]k*s*” emp.lst The expression k*s* means that k and s may not occur at all (or as many times as possible); that’s why the expression used with grep also matches wilcox.

Question 42

$

Answer 42

Matches a pattern at the end of a line

Question 43

Extended regular expressions (ERE) make it possible to

Answer 43

match dissimilar patterns with a single expression.

Question 44

The ERE set includes two special characters, (?) and (?). They are often used in place of the * to restrict the matching scope

Answer 44

+ & -

Question 45

(egrep) +

Answer 45

Matches one or more occurrences of the previous character.

Question 46

(egrep) ?

Answer 46

Matches zero or one occurrence of the previous character.

Question 47

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk ch+

Answer 47

Matches one or more occurrences of character ch

Question 48

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk ch?

Answer 48

Matches zero or more occurrence of character ch

Question 49

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk exp1|exp2

Answer 49

Matches exp1 or exp2

Question 50

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk (x1|x2)x3

Answer 50

Matches x1x3 or x2x3

Question 51

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk g+

Answer 51

Matches at least one g

Question 52

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk g?

Answer 52

Matches at least one g

Question 53

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk g?

Answer 53

Matches nothing or one g

Question 54

The Extended Regular Expression (ERE) Set Used by grep, egrep and awk GIF|JPEG

Answer 54

Matches GIF or JPEG

Question 55

(lock|ver) wood

Answer 55

Matches lockwood or verwood