Q1. What is Kernel Panic Error and How to troubleshoot it ? Explain step by step. Q2. How to reset Root user Password ? Q3. Explain Boot Process step by [ … ]

1. How to set a username and password to NEVER EXPIRE? Ans: Command to check expiration date: chage -l username -l: Lists account aging information. Command to set account to [ … ]

*File System & Disk Management** 1. **Scenario**: `df` shows 100% disk usage, but `du -sh /` reports only 60% usage. What’s  happening? **Fix**: `lsof +L1 | grep deleted` → Find [ … ]

1) What is `at` command used for? Ans:-The at command is used to schedule a one-time task at a specific time. Unlike cron, which is recurring, at runs the job [ … ]

📌 TCP/IP & Troubleshooting 1) What is the TCP 3-way handshake? Ans:-The TCP 3-way handshake is the process used to establish a reliable connection between a client and a server [ … ]

1) How do you fix a corrupted file system using fsck? Ans:- To fix a corrupted filesystem, unmount it first(umount /dev/sda1), then run fsck -y /dev/sdXN to check and repair [ … ]

1. A user complains they cannot log in. How will you troubleshoot? A)  I will first check if the user account exists and is not locked ( passwd -S username [ … ]

1. What is Nagios? A) Nagios is an open-source monitoring tool used to monitor servers, network devices, applications, and services. It alerts administrators about system issues before they become critical. [ … ]

1. What is a hard link in Linux? A) A hard link is a directory entry that directly points to the inode of a file. Multiple hard links can exist [ … ]

1. What is fdisk in Linux? A) fdisk is a command-line utility used to create, delete, view, and manage disk partitions on Linux systems. 2. How do you list all [ … ]