Linux Admin Interview Questions

The reasoning or logic behind interviewing tactics is probably one of the most trivial issues I've encountered in my career. Everyone has their method, and most of them do not work.

I have compiled few Interview Questions for Linux Admins. I will keep adding to this in the future, complete work in progress...

Questions:

Where are user accessible binaries are stored?

How do you check mounted filesystem usage?

How do you check size of folder?

How to get free inodes in filesystem?

What command do you use to verify a file type?

Command used to check all the mounted partitions?

Which command will show me the mounted filesystem is read only or read-write enabled?

What are the steps to create a persistent mount within a Linux system?

Which scripts execute at last when system gets startup?

Which script initialize the System Daemon?

What file do you edit to create message displayed on the console for every login?

Command to check which packages are installed in a Fedora based Linux system?

How do you delete a directory?

How do you delete a directory and it's recursive assets?

Where are the samba configuration files are generally stored in Fedora based Linux system?

How to start Networking service in Debian based Linux?

How do you show the IP configuration in a Debian based Linux system?

How do you list hidden files inside /abc directory?

Tell me the command to compare two ASCII files.

Tell me the filename to edit for adding NFS share?

Which Linux modules get loaded after starting NFS?

What is the command to check partition sizes?

How do you get the path of a command ?

How do you display the environment variables?
How do you set environment variables?

Explain the output of uptime command.

How do you display a list of modules loaded in memory?

What is the partition id of swap partition?

What is the LVM?

How do you create a new file with rwx-r—r-- permissions ?

What is proc?

How do you display PCI device information on Debian Linux a system?

What is the difference between Absolute & Relative Path ?

How to get only last column of ls -l output

What is and how do you add the sticky bit?

Where MBR typically stored in Linux?
What are the common log files for a Linux system?

If there are any hardware related issues, then which command you will run first to check the status?

If you exported NFS share but you are not able to access it on client then how will you troubleshoot?

How will you check the process eating up more CPU?

How do you verify if a port is open ?

If I am not able to create a single file on mounted filesystem, what can be the reasons?

Where are the kernel tunable parameters?

In which logs you will see login failure messages?

Explain a primary performance monitoring tool in Linux and how it can be used to determine any resource constraints.

How do you add a default route in Linux?

Which command is used to check Network Link is up or not?

What port does SSH protocol use by default?
What are iptables ? What are the default tables in iptables?

What is the difference between stateless & stateful firewall?

what is tcp_syncookies?

How to enable tcp_windowscalling?

Difference between Active & Passive

On which port does the FTP Server listen?

What is TCP handshaking?

How do you monitor a networking Device using SNMP ? What tools or commands?

What is the tolarance value for RAID6
What are the basic types of Virtual Hosting in Apache?
On what port does the SMB/Samba Service Listen?

When you add any user ,which files will get modified? 

What command do you use in Linux to add a user?
How do you change the user password?
How do you give a user root privileges?