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TCS · Linux & Shell Scripting
Practice Linux & Shell Scripting questions specifically asked in TCS interviews – ideal for online test preparation, technical rounds and final HR discussions.
Questions
24
Tagged for this company + subject
Company
TCS
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Subject
Linux & Shell Scripting
Explore topic-wise practice
Go through each question and its explanation. Use this page for targeted revision just before your TCS Linux & Shell Scripting round.
Linux permissions are divided into read (r), write (w), and execute (x). Read allows viewing file contents, write allows modifications, and execute lets you run the file if it’s a program or script. Each type applies separately to owner, group, and others.
For complete preparation, combine this company + subject page with full company-wise practice and subject-wise practice. You can also explore other companies and topics from the links below.
grep stands for 'global regular expression print'. It searches for specific patterns of text within one or more files. It is often used in pipelines to filter command output.
grep 'error' app.log
chown means 'change owner'. It allows an administrator to change the file owner and optionally its group. Only the root user or the file’s current owner can modify ownership permissions.
sudo chown ubuntu:devops app.log
In Bash, variables are declared without spaces around the equal sign. To use a variable later, prefix it with a dollar sign — for example, echo $var.
name=Vipul echo $name
The special variable $? holds the exit status of the most recent command. A value of 0 means success, while any non-zero value indicates an error or failure.
cp file.txt /backup/ echo $?
The cron daemon runs scheduled commands defined in crontab files. It is used for automating backups, reports, and maintenance tasks at fixed times or dates.
crontab -e 0 2 * * * /home/user/backup.sh
logrotate automatically rotates, compresses, and deletes old logs to prevent disk overuse. It’s configured using /etc/logrotate.conf and is essential for server maintenance.
First, write a shell script that copies important files to a backup directory with a timestamp. Then, schedule it in crontab to run every night using a 0 2 * * * entry for 2 AM backups.
0 2 * * * /home/admin/backup.sh
The uptime command displays the current time, system uptime, number of logged-in users, and the system load averages. It helps assess whether the machine is under heavy load or has been running continuously.
uptime
traceroute traces each hop packets pass through to reach a target. It’s useful for identifying where network delays or failures occur.
traceroute 8.8.8.8
The du command is used to measure disk usage recursively. Combine it with sort to list directories from largest to smallest, helping clean up space efficiently.
du -h --max-depth=1 /var | sort -hr | head
yum (Yellowdog Updater Modified) is used for package management on Red Hat-based systems. It handles installation, dependency resolution, and updates automatically.
sudo yum install httpd -y
systemctl status displays whether a service is active, inactive, or failed. It also shows logs from the systemd journal, helping quickly diagnose service issues.
sudo systemctl status nginx
On Debian systems, use apt update to refresh the package index, then apt upgrade to install new versions. On RHEL or CentOS, use yum update. Always run updates with sudo to apply them system-wide.
sudo apt update && sudo apt upgrade -y
The ip a command lists all network interfaces, their assigned IP addresses, and their operational states. It replaces older tools like ifconfig in modern Linux systems.
ip a
SSH (Secure Shell) connects securely to remote systems over the network. It encrypts both authentication and data transfer to protect communication from eavesdropping.
ssh user@192.168.1.10
Use ufw status numbered to list all active rules with indexes. To remove a rule, run ufw delete <rule_number>. You can add rules with ufw allow or ufw deny for specific ports or services.
sudo ufw status numbered sudo ufw delete 2
lsblk shows information about all storage devices such as disks, partitions, and mount points. It’s a quick way to check attached drives and where they are mounted.
lsblk
Use rsync or tar to perform daily backups of key directories like /etc, /home, and /var. Automate the process with cron and store backups on an external drive or remote storage. Always test restore procedures regularly.
rsync -av /var/www /backup/webdata/
Use the jobs command to list all background or stopped processes in the current shell. Bring one back to the foreground using fg %job_number or resume it in the background using bg %job_number.
jobs fg %1
bg resumes a stopped job in the background, while fg brings it back to the foreground. They are used in interactive shell sessions to manage job execution.
bg %1 fg %1
The command ls -a shows all files, including hidden ones that start with a dot. It is commonly used to inspect configuration files like .bashrc or .gitignore.
ls -a
The ps command shows currently running processes along with their process IDs. You can use options like ps aux to view all system processes.
ps aux
tar is used to group multiple files or directories into one archive file. It’s often used with gzip for compressed backups, using the -czf option.
tar -czf backup.tar.gz /home/user/