Linux Questions 1

Question 1

How do you copy all .txt files from /home/user/docs to /backup while preserving file attributes?

Answer 1

cp -p /home/user/docs/*.txt /backup/

cp -p preserves timestamps, ownership, and permissions. *.txt selects all text files in /home/user/docs.

Question 2

How do you find all files modified in the last 7 days within /var/log?

Answer 2

find /var/log -type f -mtime -7

-type f ensures only files (not directories) are found. -mtime -7 filters files modified in the last 7 days.

Question 3

How can you recursively change ownership of all files inside /data to user:group?

Answer 3

chown -R user:group /data

-R makes the command recursive, changing ownership of all files and subdirectories.

Question 4

How do you kill a process by name instead of PID (e.g., firefox)?

Answer 4

pkill firefox

pkill searches for the process by name and terminates it.

Question 5

How do you find and delete all .log files larger than 100MB inside /var/log?

Answer 5

find /var/log -name “*.log” -type f -size +100M -exec rm -f {} \;

-size +100M finds files larger than 100MB. -exec rm -f {} \; deletes each matching file.

Question 6

How do you display a real-time list of running processes sorted by CPU usage?

Answer 6

top

top provides a real-time view. An alternative is ps aux --sort=-%cpu | head -10 which lists the top 10 CPU-consuming processes.

Question 7

How do you extract only the first 3 columns from data.csv and save it as new_data.csv?

Answer 7

cut -d’,’ -f1-3 data.csv > new_data.csv

-d',' sets , as the delimiter. -f1-3 selects the first three fields.

Question 8

How do you archive all files in /project modified in the last 3 days into backup.tar?

Answer 8

find /project -type f -mtime -3 | tar -cvf backup.tar -T -

find /project -type f -mtime -3 finds files modified in the last 3 days. tar -cvf backup.tar -T - archives those files.

Question 9

How do you display the first 20 lines of the largest file in /var/log?

Answer 9

ls -S /var/log/* | head -1 | xargs head -20

ls -S lists files sorted by size (largest first). head -1 selects the largest file. xargs head -20 extracts the first 20 lines.

Question 10

How do you monitor a growing log file in real-time while highlighting “ERROR” messages?

Answer 10

tail -f /var/log/syslog | grep –color=auto “ERROR”

tail -f follows live updates. grep --color=auto "ERROR" highlights matches in color.