Text processing

Question 1

What is the ‘cut’ command used for?

Answer 1

Used for extracting text by splitting lines on delimiters/byte positions/character patterns

Question 2

How can you get the nth character from each line with ‘cut’?

Answer 2

cut -c<n> <filename></filename></n>

Question 3

How can you get the multiple characters from each line with ‘cut’?

Answer 3

cut -c1,3,4 <filename> (returns 1st 3rd and 4th characters)</filename>

Question 4

How do you get a range of characters from each line using ‘cut’?

Answer 4

cut -c1-3,6-10 <filename></filename>

Question 5

How do you get a range of bytes from each line using ‘cut’?

Answer 5

cut -b1-8 <filename> (first 8 bytes)</filename>

Question 6

How can you split lines into columns on a colon (:) delimiter and select the 5th column using ‘cut’?

Answer 6

cut -d: -f 5 <filename></filename>

Question 7

How can you use ‘cut’ on the output of another command?

Answer 7

<command></command>

[OPTIONS] | cut [OPTIONS] <filename></filename>

Question 8

What is the ‘awk’ command used for?

Answer 8

Text processing utility/language used to extract text from files or command output

Question 9

How do you out space separated columns lines of text using ‘awk’?

Answer 9

awk ‘{print $1}’ <filename> ($n is the column number)</filename>

Question 10

How can you get multiple columns using ‘awk’?

Answer 10

awk ‘{print $1,$2,$3}’ <filename></filename>

Question 11

How can you get the last column using ‘awk’?

Answer 11

awk ‘{print $NF}’ <filename></filename>

Question 12

How can you search for text using ‘awk’?

Answer 12

awk ‘/<text_search>/ {print}' <filename></filename></text_search>

Question 13

How can you split text on a delimiter using ‘awk’?

Answer 13

awk -F<delimiter> '{print $1}' <filename></filename></delimiter>

Question 14

How can you replace text using ‘awk’?

Answer 14

echo “One” | awk ‘{$1=”Two”; print $0}’ (replaces One with Two)

Question 15

How can you get all file lines longer than n bytes with ‘awk’?

Answer 15

cat <filename> | awk 'length($0) > <n>'</n></filename>

Question 16

Detail the syntax of an ‘if’ statement in ‘awk’

Answer 16

ls -l | awk ‘{if($9 == “username”) print $0;}’ - ‘{if(something) something $n;}’

Question 17

How do you print the number of fields per line using ‘awk’?

Answer 17

awk ‘{print NF}’

Question 18

What is the command ‘grep’ used for?

Answer 18

Advanced pattern matching tool for finding text within files and output

Question 19

What does ‘grep’ stand for?

Answer 19

Global Regular Expression Print

Question 20

What is the basic syntax of ‘grep’?

Answer 20

grep <search_term> <filename></filename></search_term>

Question 21

How can count occurrences of a search term in ‘grep’?

Answer 21

grep -c <search_term> <filename></filename></search_term>

Question 22

How can you ignore case in the search term in ‘grep’?

Answer 22

grep -i <search_term> <filename></filename></search_term>

Question 23

How can get matched line numbers in ‘grep’?

Answer 23

grep -n <search_term> <filename></filename></search_term>

Question 24

How can get all non-matched lines in ‘grep’?

Answer 24

grep -v <search_term> <filename></filename></search_term>

Question 25

How can use ‘grep’ on the output of another command?

Answer 25

<command></command>

[OPTIONS] | grep <search_term></search_term>

Question 26

How can you search for multiple terms with ‘egrep’?

Answer 26

egrep -i “<keyword1>|<keyword2>" <filename></filename></keyword2></keyword1>

Question 27

What is the ‘sort’ command used for?

Answer 27

Sorting text in alphabetical order

Question 28

What is the ‘uniq’ command used for?

Answer 28

Filtering out lines with repeated text

Question 29

What is the basic syntax of ‘sort’?

Answer 29

sort <filename> or <command></command> [OPTIONS] | sort</filename>

Question 30

How do list in reverse order using ‘sort’?

Answer 30

sort -r <filename></filename>

Question 31

How can you order by space-separated column number using ‘sort’?

Answer 31

sort -k2 <filename></filename>

Question 32

Detail a limitation of ‘uniq’ that means it will still sometimes display duplicate lines.

Answer 32

Input to ‘uniq’ must be sorted. ‘uniq’ does not guarantee that duplicates are removed unless they are adjacent

Question 33

How are ‘sort’ and ‘uniq’ used together?

Answer 33

sort <filename> | uniq</filename>

Question 34

How can you display duplicate counts with ‘uniq’?

Answer 34

sort <filename> | uniq -c</filename>

Question 35

How can you display only duplicated text with ‘uniq’?