Since no one else seems to have bothered with this I thought I'd post my answers. Of course this is just a shameless attempt to show off how fat my head is... ;)
Google, manpages and any other reference source is encouraged.
* Why has the writing been worn off my tab key? what am I using it for?
Tab completion & code indentation.
* What's a netmask? What is the netmask for a /23? What happens if you have the wrong netmask?
A netmask defines your IP subnet. Ie, what computers your computer will broardcast IP packets to (and expect answers from without routing packets via a router). A CIDR style netmask of /23 will give you subnet that extends from 192.168.0.1 to 192.168.1.254 with a broadcast address of 192.168.1.255. There are 510 hosts in this network. (Yeah for ipcalc). ;)
* A service has died, you've fixed it and need to restart it, how would you go about doing so?
On RedHat "service <insert service_name> restart". Or if you were paranoid: "service <insert service_name> stop; service <insert service name> stop". I'm not sure if Debian has the service command so I might instead do this: cd /etc/rc.d/init.d && ./service_name restart
* What does it mean if my computer boots up and says "L" then stops? What's wrong? How would you fix it?
A) It means you're till using lilo. B) It means lilo failed to correctly find your kernel and start it. Probably because your Master Boot Record is corrupt. I take it that L is more fatal the LI which is what I've seen the most of. I imagine each character signifies a completed stage of the LILO boot process?
* Can you compile your own kernel? Does anyone really know what MTRR is? does anyone care?
Yes, though I have not done so in years. MTRR is the Memory Type Range Register. It controls how your x86 box lays out memory for processes. I've never really had to worry about it. I specifically remember it being more important when I had an SMP machine. (Had to Google for the Acronym dfinition).
* What is ldconfig, and when would you use it? what happens if you forget to run it?
ldconfig generally gets run automatically by your package manager when you update or install a shared library. If you install a lib from source you might have to run it manually. ldconfig keeps ld.so.cache up to date with the locations of all your shared libraries (as controlled by ld.so.conf). If you don't run it your may find that ld and ld-linux can't find shared libraries when linking at compile type or dynamically at runtime.
* lost+found directories are scattered around the filesystem, what is their purpose? Can they just be removed? Are there any side effects to doing so?
When running fsck on a filesystem and it finds orphan directory entries of inodes it will create files in lost+found that contain these orphaned files. It has been a long long time since I ever had that problem. Journaling file systems seem to not suffer from this problem.
* emacs or vi?
Emacs. But I'm using vi more often these days when editing config files.
* What process has pid 1, why is this process important? Where would you configure this process? What happens if this process goes away?
init has pid 1 because it is the first process to be spawned by the kernel. It is the parent of all other processes. MostLinux systems run SysVinit which configured via /etc/inittab. If it was to die? The kernel would probably halt or reboot the system.
* Do you know what these tools are used for? ** apropos
Searching man pages.
** awk
Processing text with awk scripts (because you're crazy and don't know perl).
** cvs
Concurrent Versions System. Source code control system.
** dmesg
Prints the kernel's message ring buffer to screen.
** find
Find files using a variety of tests/criteia.
** fsck
File system check. Checks your file systems for integrity.
** grep
Search text files for substrings using regular expressions.
** locate
Query the locate database which contains all files and directories on your system. This command is only useful if the updatedb command has been run to completion. This usually occurs every night at about 4am via cron.
** screen
A command that allows you to have multiple "screens" attached to a single tty. You can think of it as a tabbed console app for text terms. ;) Also allows you to detach from a tty & logout and have your interactive processes remain running.
** sed
The venerable stream editor. Allows you to edit streams of text using regular expressions.
** ssh
Secure Shell. A much safer encrypted alternative to telnet. Also encrypted provides TCP/IP tunneling features.
** strace
Stack trace. A program that will print the call stack of a process as it runs.
** sudo
Super User Do. Allows you to delegate authority to run processes that require root access in a controlled fashion. Trendy distros like ubunto and MacOS X favour sudo over a separate root account.
** svn
Subversion. A better alternative to cvs. Does the same job only with more tricks. Supports file metadata (file modes, sym links) much better (ie, at all) than cvs. Also allows for much nicer management of directories. Many other cool features. Use it, not cvs, you wont regret it. :)
** umount
Umounts devices.
** watch
A command that allows you to repeatedly execute a command at specific intervals and watch the output. It redraws the screen so it doesn't scroll.
** wall
Write to all. Allows you to write messages to all connected ttys. Useful if you want to broadcast that the system will be going down/rebooting in X minutes etc.
** wget
Web get. Venerable console util for downloading files from the web or ftp sites. Also allows you to mirror websites.
* do you know how to use /sbin/fdisk? do you use cfdisk anyway?
Yes. When partitioning disks fdisk is a handy tool. Only other disk partioner I've used is sfdisk. Mainly because you can pipe the output of sfdisk into the input of sfdisk and have it mirror the partition table to another disk. Very handy for setting up RAID arrays.
* How do killall and killall5 differ? Have you ever got them confused? Is this bad? Were you fired?
Killall kills all processes with a particular name. Killall5 does the same but will not kill the processes in its own session. Very useful for shutdown scripts.
* Do you run screaming at the word PCMCIA? How would you configure a PCMCIA wireless card? a PCMCIA GPS? a PCMCIA flux capacitor?
I've not done this in a long time so I can't remember exactly how you go about it. But if it wasn't detected by kudzu (or similar tool) and configured for me I'd probably be able to wade my way through the /etc/pcmcia config files to get it working (if there was driver support).
* Running most programs elicits the error "Read only filesystem", what may have caused this? How would you resolve it?
You're trying to run stuff from a CDROM or a readonly mounted filesystem. You should probably add the noatime option to the fs mount options so that it doesn't attempt to update the access time of each file it executes/reads.
* how would you tell if a machine is running debian, redhat, gentoo, or windows xp?
If I couldn't look at the screen? nmap could guess the OS between Windows and Linux. To remotely tell Linux's apart? That I've never had to attempt. If they were running telnet daemons I could have a look at the issue file that might be displayed. But no one (or at least very few) is stupid enough to run an exposed telnet so if I was logged in I could check the /etc/issue file. If Apache was configured to emit the Stock status line for most distros I could look at that to guess the OS remotely too.
* what would you do to get a program run on stup?
If it has a init script in /etc/rc.d/init.d then I would use chkconfig to add the script to the right run level. If it didn't have an init script I'd have to write one first.
* What kind of files would you expect to find in /usr/share/zoneinfo, are these files important? what would happen if they were removed?
They provide time zone information to glibc. If they were removed then the only timezone I could run in successfully would probably be gmt/utc.
* I'm installing a package the depends on portmap, what is it that I'm likely to be installing? is portmap important? how would I diagnose issues with portmap?
You installing a package that uses SUN RPC. Portmap is the SUN RPC port mapper. It provides a common well known service for SUN RPC processes to contact to request the port of the daemon process the RPC client is trying to contact. Diagnosing problems with portmap I've never had to do. I imagine there are some utilities I can run to inspect process data. Usually you don't have to do anything to get portmap or NFS to work other than ensuring the right processes are enabled and the ports arn't filewalled off.
* How do I determine what ports are open on my machine? How can I tell what ports to close? Name at least two ways to "close" ports from the Internet.
netstat -l. You can close ports of processes you are not using by shutting down the process in question and configuring it not to start again at system startup and you can also firewall the ports with ipchains/iptables.
* How do I list all the hidden files in a directory?
ls -la will list all files in a directory (in long form). If you just want the "dot" files then ls -ld .* will just list all the "hidden" files.
* What does "#!/bin/sh" mean, why is it important?
#! is used by the kernel as the "magic number" for shell processes. The kernel reads the rest of the first line of the file and uses it as the executable to run and give the executable the named of the file as its first argument (after any arguments on the #! line of the shell script).
* If I had permissions "rwxr-xr-x perry fooers" who could do what? What type of file is this likely to be? What about if the permissions are 550?
The file is probably an executable or directory and everyone can run it or change directory into it. User perry could also read and write to the file/directory, everyone else can only read or execute/change directory on it.
* Whats the difference between bash and xterm?
Bash is a shell, xterm is a process that provides an X11 hosted tty to which a process like bash can attach its input/output to.
* How do I determine if swap is enabled? How would I disable it?
The command free will tell you how much swap you have. You can turn swap off with swapoff -a.
* How many primary partitions can you have on a normal x86 box? How would you get around this?
4. You can create an extended partition which will enable you to create more "logical" partitions within it. I forget how many logicals you have. I've never been in a position to run out of them though.
* I have a /boot partition, how big should this be? Is there anything special about how this partition is layed out on disk?
It should be big enough to hold as many kernels as you think a rational to have installed on your PC. I've rarely filled up a 128MB boot partition. It is generally considered to be good practice to make the /boot partition the first partition on the drive. This helps ensure buggy BIOSes can read files on it. It should also be a ext2 file system because GRUB & LILO don't generally support fancier file system types.
* fsck says "Deleted inode has zero dtime" what has happened to my disk? am I going to have to reinstall?
Your filesystem has some slight corruption. A deleted file/inode never had its deletion time set. The file was probably still open (yet had been unlinked) when your system shutdown. Fsck can repair this easily and no you shouldn't have to reinstall.
* I've forgotten my root password, what can I do about this?
You do have a boot/rescue disk yes? You can use it to boot up the machine and edit /etc/shadow to replace the password with either nothing or another password hash (say from a user you know the password of). Or if your distro doesn't prompt for the root password when you boot into single user mode you can add the argument "single" to your lilo/grub boot manager. If it does ask for the root password you can over ride this by specifying an alternative init to the kernel with the init=/bin/sh argument. Once you are in you just use passwd to reset the password.
* depmod complains about unresolved symbols? How would you resolve this issue?
Either you have old binary kernel modules in your /lib/modules/ tree for the running kernel or your kenerl lacks a static feature that a kernel module requires.
* what is important about "."'s at the beginning of a filename? What sort of files would be named like this?
It hides files from ls by default. It is the naming convention used by Unix operating systems to signify that the file is "hidden". There is nothing special about this other than it is a convention. They are generally called "dot files". They usually contain configuration data.
* I have a file with a charactor I can't type in it, how would I delete it from the cli?
You mean a filename with something strange in it. Just use a wildcard. Eg: rm ./start*end Or if it is a single character use: rm ./start?end
* Linux boots and then says it can't start my X server, what does this mean? how would I fix this?
Probably you have a misconfigured video driver, or your mouse is not plugged in or your font server is turned off. Configure, plug in or start as necessary.
* I want to have a program run every day at 3am, how would I do this?
As root? Put a link or script that runs your program in /etc/cron.daily. If the time that those are run is not 3am then use the command crontab -e to edit your crontab file. Read the crontab man page (man 5 crontab) for the file format.
* What are the best ways of determining what hardware is in my machine?
lspci, hwbrowser, lsusb.
* Have you written any wiki pages?
Yes.
* ls segfaults when run, how can I tell what files are in the current directory without using X?
for i in *;do echo $i; done
* What is a window manager? What happens if I don't have one?
A window manager manages windows in an X11 session. Ie, it allows you to move, resize, minimise, restore windows. If you don't have one the X server will put windows where ever it likes an you can't do sqwat about it.
* What's this lpd thing running? Why would I want it? Where is it's configuration usually stored? How would I submit files to it?
It is the line printer daemon. It manages printer cues. You should really install cups. ;) lpd speaks the LPD protocol and you can print a file with lpr. eg, cat /etc/passwd | lpr. You can view the queue with lpq and remove files with lprm. The config is probably in /etc/printtab. But like I said you should be running cups. ;)
* Every time I type an "s" in X I get a "z" on the screen, whats wrong? how would I fix this?
Your keyboard map is wrong. Use system-config-keyboard (on RedHat) to select the correct keyboard language. Or you can use loadkeys and kbd_mode to correct the keyboard maping. Or in X you can use xmodmap too alter the keyboard mappings.
* X needs a driver on a CD I have to run, how would I get that driver onto the machine?
mkdir -p /mnt/cdrom && mount -t iso9660 /dev/cdrom /mnt/cdrom && cp /mnt/cdrom/file ~/ && umount /mnt/cdrom
* How do I list all the rpm's installed on a machine? How do I list all the .debs installed on a machine?
rpm -qa |sort |less Dunno. Don't run debian... ;) Probably something to do with dpkg.
* click to focus? sloppy focus? or focus follows the mouse? Discuss.
Used to use sloppy focus. Have gotten used to click to focus now in Gnome.
* I have a .tar.gz file that contains the source to a program I want to install, how would I compile and install it?
tar zxfv file.tar.gz && cd dir && ./configure && make && make install
* The above program fails while installing saying "checking for zlib.h... failed" what do I do now?
yum install zlib-devel || apt-get install zlib-devel
* Should I install it in ~, /usr, /var/tmp, /opt, "/Program files/Perry's cool program" or /usr/local, discuss.
/usr/local (if you're root), some sub directory of ~ if not.
* I have a daemon that isn't working, what would the first thing I do be?
Ensure it is running.
* I have a program running on port 23/tcp open, is this a problem?
Running telnet is a problem yes. :) Unless you don't care about packet sniffers.
* what's /dev/ttyS0 likely to be? I sent "AT\n" to it, and it said something back that made me happy, what did it say?
A modem. It should say OK back and you would be happy.
* How would I set up IP masquerading?
Depends on the kernel and whether you used ipchains or iptables (for 2.4 and 2.6 kernels). With 2.6 and iptables you might do this: iptables -A FORWARD -i $INTERNAL_IF -j ACCEPT iptables -A FORWARD -i $EXTERNAL_IF -j ACCEPT iptables -t nat -A POSTROUTING -o $EXTERNAL_IF -j MASQUERADE You would also have to enable ip packet forwarding with: sysctl -w net.ipv4.ip_forward=1
* what's /etc/issue used for? why is it different to /etc/motd? Can I arbitarily edit either file?
The issue file is displayed by telnetd and getty's to identify hosts when you connect. The motd file (message of the day) is displayed after you login before your shell prompt appears. You can edit motd as much as you like. /etc/issue might be over written when you boot up.
* eth0 has an IP address of 127.255.255.255, name two problems with this address being used on eth0.
It appears to be a board cast address. It is also on the 127.0.0.0 network which is designed for use as loopback and will be dropped by routers and not understood correctly by machines on your subnet.
* Explain the difference between an oops and a panic.
An kernel opps is when the kernel generates a page fault that wasn't expected but can be recovered from. A panic is generally a kernel bug in the kernel interrupt handlers/scheduler that can not be recovered from. A panic halts the machine. And opps does not.
* I have an internal network, what IP address(es) can I use for my machines? what addresses shouldn't I use?
Use a subnet in 192.168.0.0/16, 172.16.0.0/12 or 10.0.0.0/8. You should not use pretty much anything else.
* I use ihug for dialup internet, how would I set this up?
Use whatever your distro uses to support PPP dialup. If this requires special "ihug" stuff I don't know what it is. With RedHat/Fedora I would configure a PPP modem link with system-config-network.
* Whenever I try and use the internet it says "Unknown host", I can ping machines by IP address, whats probably wrong? what config file(s) would I check? How would I fix this?
Your DNS resolver is not configured. Check /etc/resolv.conf has the correct nameserver lines for your uplink.
* I have no default route, how do I add a new one without rebooting? If I know my IP and netmask, at a guess what should I set the default gateway to?
If you're on a 192.168.0/24 subnet then, as root: route add default gw 192.168.0.254
* What is 0x20 in decimal? binary? octal? does anyone care?
32 dec, 40 octal, 100000 binary. No. ;)
* /proc/interrupts is showing a lot of interrupts on IRQ 0, is this something I should be worried about?
IRQ 0 is the system timer and no you should not be worried.
* inetd is a cool program, what does it do? What happens if it's not running?
inetd is a "super daemon" it manages other daemons like telnet, rlogin, pop3d, imapd etc. Most distros now use xinetd which is more secure and much easier to configure. If it isn't running then you wont be able to access any services it manages.
* I'm at an Installfest, and I have a problem I can't solve, what should I do?
Google. ;) Ask someone else for help.
* What's NAT? Why is it evil?
Network address translation. It isn't that evil. Though it does make it hard for outside machines to contact machines in your local lan if the protocol (particularly udp protocols) hasn't been written very well.
* I installed a new kernel and now my computer panics during boot, what should I do?
Tell LILO/GRUB to use your old kernel. You did leave your old kernel in place didn't you?!
* If you had a computer that had all the problems outlined above, would you switch to macos?
No. But I'd buy a Mac Mini for my iPod. ;)
If you want to discuss your answers to questions please reply to me *OFF LIST* so that other people have a chance to think about them without the answers being given away.
Do I get a prize? Regards -- Oliver Jones » Roving Code Warrior oliver(a)deeperdesign.com » +64 (21) 41 2238 » www.deeperdesign.com