grep

Question 1

What does the -i option do in grep?

Answer 1

The -i option makes the search case-insensitive. For example, ‘grep -i error file.txt’ matches ‘error’, ‘Error’, and ‘ERROR’.

Question 2

What does the -v option do in grep?

Answer 2

The -v option inverts the match, displaying lines that do NOT match the pattern. For example, ‘grep -v DEBUG file.txt’ excludes lines containing ‘DEBUG’.

Question 3

What does the -c option do in grep?

Answer 3

The -c option counts the number of matching lines instead of displaying them. For example, ‘grep -c keyword file.txt’ outputs the number of lines containing ‘keyword’.

Question 4

What does the -n option do in grep?

Answer 4

The -n option displays line numbers alongside matching lines. For example, ‘grep -n "pattern" file.txt’ shows matching lines with their line numbers.

Question 5

What does the -l option do in grep?

Answer 5

The -l option lists only the names of files containing matches. For example, ‘grep -l "error" *.log’ lists log files containing ‘error’.

Question 6

What does the -L option do in grep?

Answer 6

The -L option lists only the names of files that do NOT contain any matches. For example, ‘grep -L "keyword" *.txt’ lists files that do not contain ‘keyword’.

Question 7

What does the -r option do in grep?

Answer 7

The -r option enables recursive search through directories. For example, ‘grep -r "keyword" /project’ searches all files in the /project directory and subdirectories.

Question 8

What does the -w option do in grep?

Answer 8

The -w option matches whole words only. For example, ‘grep -w "cat" file.txt’ matches ‘cat’ as a whole word but not ‘category’.

Question 9

What does the -A option do in grep?

Answer 9

The -A option displays ‘n’ lines after each match. For example, ‘grep -A 3 "error" file.log’ shows the matching lines and 3 lines after each match.

Question 10

What does the -B option do in grep?

Answer 10

The -B option displays ‘n’ lines before each match. For example, ‘grep -B 2 "404" file.log’ shows 2 lines before each matching line.

Question 11

What does the -C option do in grep?

Answer 11

The -C option displays ‘n’ lines of context before and after each match. For example, ‘grep -C 1 "failed" file.log’ shows 1 line before and 1 line after each match.

Question 12

What does the -e option do in grep?

Answer 12

The -e option allows specifying multiple patterns. For example, ‘grep -e "pattern1" -e "pattern2" file.txt’ matches lines containing ‘pattern1’ or ‘pattern2’.

Question 13

What does the -f option do in grep?

Answer 13

The -f option allows reading patterns from a file. For example, ‘grep -f patterns.txt file1.txt’ matches lines containing patterns listed in patterns.txt.

Question 14

What does the –color option do in grep?

Answer 14

The –color option highlights matching text in the output. For example, ‘grep –color "keyword" file.txt’ highlights ‘keyword’ in the results.

Question 15

What does the -q option do in grep?

Answer 15

The -q option runs grep quietly, suppressing all output. For example, ‘grep -q "ERROR" file.txt && echo "Error found"’ outputs ‘Error found’ if ‘ERROR’ exists.

Question 16

What does the grep command ‘grep -i "error" /var/log/syslog’ do?

Answer 16

It performs a case-insensitive search for the word ‘error’ in the /var/log/syslog file and displays all matching lines.

Question 17

What does the grep command ‘grep -v "debug" /var/log/messages’ do?

Answer 17

It displays all lines from /var/log/messages that do not contain the word ‘debug’.

Question 18

What does the grep command ‘grep -c "timeout" application.log’ do?

Answer 18

It counts the number of lines in application.log that contain the word ‘timeout’.

Question 19

What does the grep command ‘grep -n "keyword" notes.txt’ do?

Answer 19

It searches for the word ‘keyword’ in notes.txt and displays the matching lines along with their line numbers.

Question 20

What does the grep command ‘grep -l "failure" /var/log/*.log’ do?

Answer 20

It lists the names of log files in /var/log that contain the word ‘failure’.

Question 21

What does the grep command ‘grep -L "success" results.txt’ do?

Answer 21

It lists the names of files that do not contain the word ‘success’ in results.txt.

Question 22

What does the grep command ‘grep -r -i "critical" /etc’ do?

Answer 22

It recursively searches for the word ‘critical’ in all files under the /etc directory, case-insensitively.

Question 23

What does the grep command ‘grep -w "error" /var/log/syslog’ do?

Answer 23

It searches for whole-word occurrences of ‘error’ in /var/log/syslog and excludes matches where ‘error’ is part of another word.

Question 24

What does the grep command ‘grep -A 2 "failed" logs.txt’ do?

Answer 24

It searches for lines containing ‘failed’ in logs.txt and displays each matching line along with the 2 lines after it.

Question 25

What does the grep command ‘grep -B 3 "denied" auth.log’ do?

Answer 25

It searches for lines containing ‘denied’ in auth.log and displays each matching line along with the 3 lines before it.

Question 26

What does the grep command ‘grep -C 3 "password" server.log’ do?

Answer 26

It searches for lines containing ‘password’ in server.log and displays each matching line along with 3 lines of context before and after the match.

Question 27

What does the grep command ‘grep -f patterns.txt -i /var/log/syslog’ do?

Answer 27

It reads patterns from patterns.txt and performs a case-insensitive search for those patterns in the /var/log/syslog file.

Question 28

What does the grep command ‘grep –color -n "login" access.log’ do?

Answer 28

It searches for the word ‘login’ in access.log, displays matching lines with their line numbers, and highlights the matches in color.

Question 29

What does the grep command ‘grep -q "error" application.log && echo "Error found"’ do?

Answer 29

It performs a quiet search for ‘error’ in application.log. If a match is found, it outputs ‘Error found’.

Question 30

What does the grep command ‘grep -r -l "connection lost" /var/log/’ do?

Answer 30

It recursively searches for ‘connection lost’ in all files under /var/log and lists the names of the files containing the match.

Question 31

What does the -d option do in the cut command?

Answer 31

The -d option specifies the delimiter used to separate fields. For example, ‘cut -d , -f 1 file.csv’ extracts the first field from a CSV file.

Question 32

What does the -f option do in the cut command?

Answer 32

The -f option selects which fields to display from a delimited file. For example, ‘cut -f 2 file.txt’ displays the second field from a tab-delimited file.

Question 33

What does the -c option do in the cut command?

Answer 33

The -c option selects specific characters from a line. For example, ‘cut -c 1-5 file.txt’ displays the first 5 characters of each line in file.txt.

Question 34

What does the -b option do in the cut command?

Answer 34

The -b option selects specific bytes from a line. For example, ‘cut -b 1-4 file.txt’ displays the first 4 bytes of each line in file.txt.

Question 35

What does the -d option do in the sort command?

Answer 35

The -d option sorts input data by considering only alphanumeric characters, ignoring non-alphanumeric characters. For example, ‘sort -d file.txt’ sorts the file with alphanumeric sorting.

Question 36

What does the -n option do in the sort command?

Answer 36

The -n option sorts the input numerically. For example, ‘sort -n numbers.txt’ sorts the lines of numbers.txt in ascending numerical order.

Question 37

What does the -r option do in the sort command?

Answer 37

The -r option reverses the order of the sort. For example, ‘sort -r file.txt’ sorts the contents of file.txt in descending order.

Question 38

What does the -u option do in the sort command?

Answer 38

The -u option removes duplicate lines from the sorted output. For example, ‘sort -u file.txt’ sorts file.txt and removes any duplicate lines.

Question 39

What does the -k option do in the sort command?

Answer 39

The -k option allows sorting by specific fields. For example, ‘sort -k 2 file.txt’ sorts file.txt based on the second field of each line.

Question 40

What does the -t option do in the sort command?

Answer 40

The -t option specifies the delimiter for sorting fields. For example, ‘sort -t , -k 2 file.csv’ sorts the file by the second field in CSV format.

Question 41

What does the –version option do in the sort command?

Answer 41

The –version option displays the version of the sort command. For example, ‘sort –version’ outputs the version information for the sort utility.

Question 42

What does the –check option do in the sort command?

Answer 42

The –check option checks if the input is already sorted without sorting it. For example, ‘sort –check file.txt’ returns an error if the file is not sorted.

Question 43

What does the -f option do in the sort command?

Answer 43

The -f option ignores case when sorting. For example, ‘sort -f file.txt’ sorts file.txt in a case-insensitive manner.

Question 44

What does the -b option do in the sort command?

Answer 44

The -b option ignores leading spaces when sorting. For example, ‘sort -b file.txt’ will sort the lines of file.txt while ignoring any leading whitespace.

Question 45

What does the -M option do in the sort command?

Answer 45

The -M option sorts by month names. For example, ‘sort -M months.txt’ sorts months.txt by the month names (e.g., Jan, Feb, Mar).

Question 46

What does the -z option do in the sort command?

Answer 46

The -z option sets the input and output to be delimited by null characters instead of newlines. For example, ‘sort -z file.txt’ treats nulls as delimiters in file.txt.

Question 47

cut -d , -f 1 employees.csv

Answer 47

This command extracts the first column from a comma-separated CSV file named employees.csv.

Question 48

cut -d : -f 2 password_file.txt

Answer 48

This command extracts the second field (usually the password) from a colon-separated file such as a password file.

Question 49

cut -f 1-3 data.txt

Answer 49

This command extracts the first three fields from a tab-delimited text file named data.txt.

Question 50

cut -c 1-5 log.txt

Answer 50

This command extracts the first five characters from each line in log.txt.

Question 51

cut -b 1-4 report.txt

Answer 51

This command extracts the first 4 bytes from each line of report.txt.

Question 52

sort -d names.txt

Answer 52

This command sorts the lines of names.txt alphabetically, considering only alphanumeric characters.

Question 53

sort -n numbers.txt

Answer 53

This command sorts the contents of numbers.txt numerically, from lowest to highest.

Question 54

sort -r reverse.txt

Answer 54

This command sorts the contents of reverse.txt in reverse (descending) order.

Question 55

sort -u list.txt

Answer 55

This command sorts list.txt and removes any duplicate lines.

Question 56

sort -k 2 people.txt

Answer 56

This command sorts people.txt based on the second field (e.g., last names).

Question 57

sort -t , -k 3 data.csv

Answer 57

This command sorts data.csv by the third field using a comma as the delimiter.

Question 58

sort -f names.txt

Answer 58

This command sorts names.txt in a case-insensitive manner.

Question 59

sort -b input.txt

Answer 59

This command sorts input.txt while ignoring leading spaces.

Question 60

sort -M months.txt

Answer 60

This command sorts the months.txt file containing month names in chronological order.

Question 61

sort -z file.txt

Answer 61

This command sorts file.txt where records are separated by null characters instead of newlines.