Unix Admin

Unix System Administrator Questions

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Unix

• What's the latest version of the Linux kernel?

• Can you tell me how you would make a directory group writable? how would you rm a file that starts with a minus.

• Filesystem is full, but no large files seem to be present. What do you do? What could it be?

• What's the system.map file?

• Could you write a cd command in the programming language of yoru choice ?

• What does the fork() system call return?

• explain the steps between sending an e-mail and it being received.

• What language do you generally use for scripting;
  • shell: Do you know what the "shift" command does? What variable contains the return value? of the last process?
  • Perl: Can you explain what tainting is? Can you explain what the -w command line argument does?
  • Python: Can you explain what a dictionary is?

• A command is going haywire, can you describe the steps you would take to diagnose the problem? How would you collate information useful for forming a detailed bug report?

• What is IRQ balancing, how would you do it? What does 64-bit computing really mean?

Network administration:

• Can you explain how to work out how many addresses are usable in a standard subnet?

• If you had to write some code to see if an IP address was in a particular subnet, how would you do it?

• What is a VLAN? How do they work?

• Can you explain some differences between, and give examples of when you would use HSRP, VRRP and BGP for resilience?

• Give an example of when you might use, or have used, tcpdump/ethtool/sniffer ?

• Updating ACLs safely, how would you go about it?

• Can you describe the three-way handshake, roughly?

• What's a link-state protocol?

• Do you know what an administrative distance is? Any examples?

• PKI: Can you describe, roughly how Public Key Cyrpto works? If a protocol is encrypted, how can it be proxied?