Linux Administrator Interview questions

Linux Administrator Interview questions
1)Advantages/disadvantages of script vs compiled program.
2)Name a replacement for PHP/Perl/MySQL/Linux/Apache and show main differences.
3)Why have you choosen such a combination of products?
4)Differences between two last MySQL versions. Which one would you choose and when/why?
5)Main differences between Apache 1.x and 2.x. Why is 2.x not so popular? Which one would you choose and when/why?
6)Which Linux distros do you have experience with?
7)Which distro you prefer? Why?
8)Which tool would you use to update Debian / Slackware / RedHat / Mandrake / SuSE ?
9)You're asked to write an Apache module. What would you do?
10)Which tool do you prefer for Apache log reports?
11)Your portfolio. (even a PHP guest book may work well)
12)What does "route" command do?
13)Differences between ipchains and iptables.
14)What's eth0, ppp0, wlan0, ttyS0, etc.
15)What are different directories in / for?
16)Partitioning scheme for new webserver. Why?

How to check all open ports on linux machine and block unused ports?

netstat -t
#nmap -v localhost for tcp
#nmap -sU localhost for udp

#netstat -tulp
or
#netstat -tulpn

to verfy the open ports

What is the main advantage of creating links to a file instead of copies of the file in linux

What is the main advantage of creating links to a file instead of copies of the file in linux?

Question :What is the main advantage of creating links to a file instead of copies of the file?
Answer :The main advantage is not really that it saves disk space (though it does that too) but, rather, that a change of permissions on the file is applied to all the link access points. The link will show permissions of lrwxrwxrwx but that is for the link itself and not the access to the file to which the link points. Thus if you want to change the permissions for a command, such as su, you only have to do it on the original. With copies you have to find all of the copies and change permission on each of the copies.
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