chebe: (AsciiC)
We have many different kinds of Operating Systems, each with its own pluses and minuses. I think this is a very good, and important, thing. It means you have the scope to find the one that suits you just right, to enable a kind of symbiosis between you and your machine. I remember the days when you had to use Windows. I, everyday, encounter people who tell me I have to use Mac. Multiple times a day I come across people who tell me why their *nix flavour is the best. It drives me nuts. In my personal sphere the worst offenders are the Debian and Ubuntu users. I've no problem with people talking about their OS, engaging in open discussion is healthy and enlightening. It's when that conversation happens to the exclusion of all other OSs that I get annoyed. And not simply because I'm a Fedora user.

Increasingly in college we're having Ubuntu forced upon us. It makes sense, there are people in my course unfamiliar with linux, and it is widely believed to be the easiest to get into. But, they say X works with linux, when they mean Ubuntu. They give instructions only for Ubuntu. Documentation is only written for Ubuntu. There is a massive dependency on "do this and it just works". Only, when you're on another flavour, and trying to figure out why it doesn't, there are no pointers, and the instructors can offer no help. It kinda defeats the purpose don't you think? To replace one ubiquitous system with another, with equally limited knowledge of how it actually works.

Okay, my little rant is over. Here's some things you might find helpful, if you're a Fedora user.
  • When you yum install python you mightn't get everything you need. I was told to get python-usb, what I needed was yum install pyusb.

  • If you're doing a forensics course and you're being told to grab things like vinetto and reglookup you'll notice they aren't in your repos. You need the CERT repo. Save the PGP key, and add it: rpm --import forensics.asc. Download the repo rpm for your version of Fedora, and install it: rpm -ivh cert-forensics-tools-release-13.rpm. (I realise I do this in a kooky way, and there are probably better ways, but I'm set in mine :) Now, updatedb to sync before you use yum. You can install everything: yum install CERT-Forensics-Tools, or just what you're looking for, e.g. yum install reglookup.

  • gvimdiff. I had vim installed, I'm pretty sure I had diff installed. But I couldn't get gvimdiff (or vimdiff) to work. It magically sorted itself out when I realised the g => yum install vim-X11.


  • There, now we can all get back to enjoying the diversity.
    chebe: (Default)
    Previously:
    - Manually mounting
    - Manually setting permissions to read/write

    Today, creating live-USB discs, and manual reformatting.

    It began like this. The screen on my laptop broke. Big stripe from top to bottom, width of the hinge, all gone white. But that was okay, I took out the five year insurance, so off it went for repair. This left me with just my EEE netbook. It had a nicely functioning Fedora 11, but it's coming to the end of it's life now. I didn't want to upgrade to 12 before as I felt they were trying too many new things all at once. And I'm apprehensive of the new bootloader. But now with 13 they've had time to get it all working nicely. Time to take the leap.

    I looked up the options. Upgrading seemed attractive. preupgrade looks fairly shiney, but my /boot partition was too small at the previously recommended 200MB, and my router is in a really awkward place to enable me to sit plugged into it for a while. So, other options, upgrade from media, install from live media. I didn't have any blank CDs or DVDs handy (I've an external DVD-drive so that's not a problem for my EEE), so I thought I'd try out the Live CD on USB thing. But the live CDs don't upgrade, only install. And sure, they've changed the recommended partitions, /boot is now 500MB, and /home gets its own. Okay, why not, let's give it a go.

    Well, the good news is the images came down quickly. The rest is a bit of a saga.

    A bit of a ramble )

    In summary, I don't know why I had these problems when others don't seem to. Every program I used was Fedora based. The only thing I can think of is that the USB drive was NTFS before I reformatted it for the first time. Or that the instructions are incomplete. But, what I learned is how to manually use mkfs and that (by default at least) it doesn't assign a label. Also, I'll think I'll stick to DVDs in the future.
    chebe: (Default)
    Problem: Linux uses up your 'extra' RAM for cache. But often refuses to free it when it's needed.

    Solution: sync; echo 3 > /proc/sys/vm/drop_caches

    Props: http://www.scottklarr.com/topic/134/linux-how-to-clear-the-cache-from-memory/

    *edit*
    http://www.linuxatemyram.com/
    http://www.linuxatemyram.com/play.html
    https://help.ubuntu.com/community/SwapFaq (to set swappiness)
    chebe: (Default)
    I'm referring to this entry: http://chebe.dreamwidth.org/6931.html

    The information presented therein is incomplete at best, inaccurate and unhelpful at worst. Here's the update.

    Problem:
    Log in to your desktop (graphically, over vnc, etc) and nothing gnome related is loading properly. You see errors like:
    "Failed to contact configuration server; some possible causes are that you need to enable TCP/IP networking for ORBit, or you have stale NFS locks due to a system crash. See http://www.gnome.org/projects/gconf/ for information. (Details - 1: IOR file '/tmp/gconfd-oracle/lock/ior' not opened successfully, no gconfd located: No such file or directory 2: IOR file '/tmp/gconfd-oracle/lock/ior' not opened successfully, no gconfd located: No such file or directory)"

    You try gconftool-2 --spawn or similar, and receive the same error.

    You look for those files, and they don't exist.

    You edit /etc/syslog.conf to include user.* /var/log/user. You restart the syslog daemon /etc/init.d/syslog restart or service syslog restart. Reproduce the error, and open the log at /var/log/user, where you find:
    "Mar 15 10:40:51 mycomputer gconfd (root-6666): Bad permissions 711 on directory /tmp/gconfd-root"

    Solution:
    ls -ahl /tmp and look for any gconfd-{user} files. These permissions need to be private. That would look like:
    drwx------ 3 root root 4.0K Mar 15 10:53 gconfd-root
    in case you were wondering.

    To fix, chmod 700 /tmp/gconfd-{user}

    Aside:
    Annoyingly this seems to be a side-effect of installing a certain product in work. It happens every time. But now that I know how to fix it, it's all good.
    chebe: (Default)
    Problem: PC system beep. Need I say more?

    Solution:

    - Immediate switch off: /sbin/rmmod -v pcspkr

    - Stop it from loading back up: vim /etc/modprobe.d/blacklist
    And append: blacklist pcspkr
    chebe: (Default)
    On RHEL Server 5.3, if you wish to permit access from other machines on your network through a new port (one not commonly used) you add it as usual through iptables:
    /sbin/iptables -A INPUT -s 192.168.0.9 -d 192.168.0.8 -p tcp --dport 66666 -j ACCEPT

    To save the new rule to keep it past reset:
    /sbin/iptables save
    /etc/init.d/iptables save

    But, the new port will not take effect unless it is also added through the GUI. From the Desktop menu go to:
    System > Administration > Security Level and Firewall

    On the Firewall Options tab, expand Other ports, and Add your port and protocol. Apply, and OK out. Now the port should be opened immediately.



    On SLES 10.0, SP1, there is no iptables. Instead there is SuSEfirewall2. To open a port open the config file: /etc/sysconfig/SuSEfirewall2, find the line with FW_SERVICES_EXT_TCP="" (in vim normal mode type /what you're looking for, n to move through the list, N to go backwards) and add your port number to the space separated list. Exit and save. Reload rules with command: SuSEfirewall2

    Things I Needed To Know

    2009-Dec-19, Saturday 01:56 pm
    chebe: (Default)
    Problem: USB flash drive is mounting as read-only, making it useless.

    Solution:
    0. get root permissions, su root, or run everything through sudo
    1. umount the drive
    2. df -h to find your drive
    3. fsck -a /dev/sdb
    4. mount -t vfat /dev/sdb /home/user/folder

    Be happy, you can write again!

    Things I Needed to Know

    2009-Dec-02, Wednesday 10:32 am
    chebe: (South Park)
    Graphical System Monitor doesn't display all processes. For a more accurate view use top.

    rtvscand is anti-virus, every time you copy a file it starts up to scan the file. When copying a very large collection of files this causes the CPU to deadlock, and essentially disable the machine's ability to keep copying. This results in transfers taking up to 4/5 times (in my personal experience) longer than on a Windows machine right beside it. To fix the problem, if you trust the source of the files: pkill -9 rtvscand
    chebe: (South Park)
    (Please see EDIT at bottom of entry.)
    Problem:
    - Version 1:
    Log into any account to be greeted by many popup dialog boxes from gnome saying something like:

    "Failed to contact configuration server; some possible causes are that you need to enable TCP/IP networking for ORBit, or you have stale NFS locks due to a system crash. See http://www.gnome.org/projects/gconf/ for information. (Details - 1: IOR file '/tmp/gconfd-oracle/lock/ior' not opened successfully, no gconfd located: No such file or directory 2: IOR file '/tmp/gconfd-oracle/lock/ior' not opened successfully, no gconfd located: No such file or directory)"

    Note; background remains black, menubars don't load, but icons are visible.

    Jiggery poke around with some settings, deleting lock files and playing around with permissions, then problem becomes:


    - Version 2:
    When trying to log into your Linux machine as a user through the UI you see an error like this:

    "GDM could not write your authorization file. This could mean that you are out of disk space or that your home directory could not be opened for writing. In any case it is not possible to login. Contact system administrator."

    Note; logging in as root works fine.

    Possible Solution:
    1. Computer is out of hard-drive space, check with df -h
    Not my problem.

    Possible Solution:
    2. .Xauthority file doesn't have correct permissions, check with ls -l /home/user
    Not my problem.

    Possible Solution:
    3. /tmp directory doesn't have correct permissions, check with ls -l /
    This is my problem. Fix with chmod 777 /tmp and restart. Likely to have solved the entire problem simply and quickly in the first place.

    Reference, and props: http://hiox.org/index.php?id=276


    EDIT: (15-March-2010)
    This problem as in version 1 re-presented itself to me. This time I managed to get it fixed straight from the off. The solutions previously presented only work for version 2. For version 1 it is very simple. Your /tmp/gconf-{user} needs to be private. You have to chmod 700 /tmp/gconfd-{user}.
    Please see http://chebe.dreamwidth.org/14683.html for further information.
    chebe: (South Park)
    Welcome to the first in the series of simple things I didn't need to know until I really, really did. This information is in note form, meaning very sumamrised. It's put here to jog my memory when I next need it. This issue is manually mounting a usb flash drive from the terminal in Linux.

    Reference, and props: http://www.novell.com/coolsolutions/feature/11637.html

    lsusb
    : lists the devices currently plugged into your usb ports.

    dmesg | grep -i "SCSI device"
    : lists the SCSI devices currently connected. Could be a hard-drive, typically a flash drive, look for the one with the right capacity, i.e. sdb

    mount -t vfat /dev/sdb /home/Desktop/folder
    : mount the drive to a folder, in vfat format, which most flash drives are.
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