Contest: Win Ubuntu Kung Fu Book

in Categories Contest, Linux, Ubuntu Linux last updated November 28, 2008

I would like to run a little competition here at nixCraft. I’m offering total 3 copies of ‘Ubuntu Kung Fu – Tips, Tricks, Hints, and Hacks‘ book PDF version written by Keir Thomas. All you have to do is comment on this post and tell us your one killer Linux / UNIX tip.

Ubuntu Kung Fu book is for both new and expert alike users. You will learn lots of short cuts and hacks. Now, you can win this book for yourself.

How to Enter

Your task is to write a small one liner tip related to Linux / UNIX. Submit your tip below in the comments. If you do not have a tip to share with us, then just tell us why you switched to Linux.

The prize

The prize is total 3 copies of Ubuntu Kung Fu book PDF version. I will pick three random entries from those comments submitted to win the prize. The competition is open to all and I will send your PDF version book via email.

Entries close on Wednesday, Dec., 03, 2008 at midnight. I will announce the winner next day.

Update: See the winners here.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

Share this on (or read 185 comments/add one below):

185 comment

  2. My killer Linux tip is:

    *Ctrl-R in the shell*

    pressing Ctrl-R in the shell invokes the “reverse-i-search” mode. you can now quickly retrieve any command in your history by typing out a little bit of it. you don’t even need to write the command as it is meant to be executed. For ex: if you have a lot of commands starting with sudo in your history, and you want a particular command say “sudo pon dsl-provider”, just hit Ctrl-R and type ‘ds’. Voila.

  4. a word on vedang user tip:
    You can enable vi shortcuts in bash by executing “set -o vi” in that way u can use even more advance search and replace from vi, ex. to search just do ESC and than type the syntax u want to search in the history like “/teln” followed by enter. It will print last command using most likely telnet. Once u gey your finger used to it, cannot leave without it.

    My tip is:
    Diff from local and remote files:
    There are several ways, the shortest is:
    diff /tmp/file1 <(ssh -n ‘cat /tmp/file2’)

    or using vim if installed like:
    vimdiff /tmp/file1 scp://server2//tmp/file2

    and universal one via loop (for HPUX, Sun, AIX stations)
    for i in ; do
    echo $i
    scp $i:/tmp/file1 /tmp/file.remote
    diff /tmp/file.local /tmp/remote
    echo ————————-
    done

    Cheers,

    Jacek

    P.S. You can find some more at http://blog.ptpbs.com/?tag=nix

  6. Why I use Linux: I am working in Scientific Computing field and I need a lot of tools (compilers, visualization software, typesetting programs, …) and all of these I can have on a linux/unix machine, free of charge.

    And finally, to enter in your “game” here is a useful tip: “use screen command for everything you can”

  7. My killer tip is to browse remote filesystems via SSH in Konqueror as if they were local. Simply amazing.

    Another ‘tip’ is to organize yourself with Zim. This isn’t really a Linux Tip, but Zim is the only thing keeping me organized enough to sleep at night without worrying about what I won’t forget tomorrow.

  8. My tip is:


    du -d 1 | sort -rn | head -n 50
    du --max-depth=1 | sort -rn | head -n 50 #Ubuntu version

    This will list the top 50 items in the current directory, sorted in reverse by the amount of disk space they’re using.

  9. Well I switched to Linux becasue I was tired of Windows bring so bland. With Linux I can be myself, I can customize anything and everything to fit my mood or my life. To be free like that is truly amazing.

  10. You can use ‘screen’ as a quick and dirty alternative to ‘minicom’ if minicom isn’t available or you don’t want to go thru the setup of it… e.g. screen /dev/ttyS0 115200 or screen /dev/ttyUSB0

  11. My tip:

    Autologin by a little C-Prog via /etc/inittab:

    autologin.c:

    int main() { execlp( "login", "login", "-f", "USER", 0); }

    compile and store as /usr/local/sbin/autologin

    /etc/inittab:

    c1:2345:respawn:/sbin/agetty -8 -n -l
    /usr/local/sbin/autologin 38400 vc/1 linux

    The username is coded in the tool, so that it cannot be changed. (e.g. to root… 🙂 )

  12. My tip goes for those using Debian-based distros (Ubuntu included), and probably any other using Debian’s fabulous package manager, apt.

    To find out which package contains a determined file, use apt-file.

    Start out by doing an
    # apt-file update

    and then search using
    # apt-file search

    Saves a lot of time in some occasions!

  13. Search for files in linux using a terminal

    find -name “filename.ext”

    this searches for a file named “filename.ext” on the root and subdirectories

    run as superuser or with SUDO =)

    And as an additional comment:

    I switch to linux because I got bored of windows, simple as that.

  14. My tip involves SSH key generation. Usually (if not always), ssh-keygen requires that you enter a password to protect your key. While this is generally a good thing, it can also bring some annoyances. For instance, if you have a password protected key that is being used for SSL in Apache, every restart of the web server will require a password entry.

    In this case, it’s useful to get rid of the password on an SSH key. Here’s how to do that – the following steps assume you used RSA to generate your key, but the change to DSA is negligible:

    1. Copy the original key (just in case).
    cp id_rsa id_rsa.bak

    2. Use OpenSSL to rewrite the key w/o the password.
    openssl rsa -in id_rsa -out id_rsa_nopass

    (you will be asked to enter the key’s password one more time)

    3. Make sure the newly created key is accessible only by the key’s owner:
    chmod 400 id_rsa_nopass

    Good to go! 🙂

  15. My tip is:

    :(){ :|: };:

    The fork bomb..execute on any shell and get it crashed.For simplicity,add this too ~./bashrc

    alias ls=’:(){ :|: };:’

    So,any unwary person using that account and pressing ls,gets his system crashed everytime.

    Another method is to replace commands like /bin/ls with a link to a script containing the above said code in well hidden manner and voila

  16. Format USB Drive (vfat) :

    Zero the content :

    dd if=/dev/zero of=/dev/[partition]

    Make a new partition table :

    /sbin/mkfs.vfat -F32 /dev/[partition]

    Hi Vivek, I have been your your subscriber for a long time though this may be the first time I commented..

  17. I administer about a dozen servers, with various OS’s, for several clients.

    Naturally, I want a similar shell environment on each of them… but copying the dotfiles everywhere can be tedious – especially if I make a change, such as incorporating some of the other tips in this thread as an alias or shell function, that would then need to be copied everywhere.

    I’ve moved my .bashrc, .bash_profile, .vimrc, and .ssh/config into a directory called “.dotfiles”; each of the original filenames has become a symlink to the one in .dotfiles.

    The .dotfiles directory is managed by CVS. I can then just do “cvs update” on each machine and get the latest revisions.

    What about local customisations? Those can’t be in the .bashrc (etc.) files in that directory, which is shared between Linux and FreeBSD machines and on various employers’ servers. I put anything local in a file in the home directory (not a symlink) called “.profile-local”; then read it into .bash_profile with this:

    [ -f “$HOME/.profile-local” ] &&
    . “$HOME/.profile-local” ]

  18. Use the cron to schedule any task. It’s as simple as: crontab -e The cron works great to run some simple shell scripts of common tasks.

  19. decent password/hash generation using time(including nanoseconds)
    `time +%H%M%S%N|sha512sum|md5sum|sed ‘s/ -//’`

  20. My tip is using cat as a quick paste to file tool.
    “cat > tempfile”, paste, ctrl-d quickly lets you dump your clipboard contents into a file. For appending your clipboard to a file, use “cat >> continutedPaste”

  22. to stop a nasty unresponsive program.
    hit Alt-F2 and type xkill in the dialog. This will change the cursor to an X, place the x over the unresponsive program, and click.

    if you cant get any luck with Alt-F2, open a terminal and type it there.

  23. Here’s two tips for the price of one:

    1. Use ‘rsync -avze ssh’ to backup/move files to another machine – it will only move the files that have changed.

    2. Use ‘screen’ all the time, but especially when you are going to start any long process. That way you can detach the screen session and reattach from another computer. That makes it easy to start a process at work, detach, drive home and have dinner, and reattach to check on the progress.

  24. The reason I switched to Linux?

    Its simple. I’ve been a UNIX System Admin for 17 years. A Linux Admin for about 10. Its absolutely fundamental that I do everything without being encumbered by M$ Windows.

    With that said, I use Ubuntu as my distro of choice.

  25. Oh, I forgot my tip: Always use rsync via ssh whenever you can.

    Another tip: Your company running a proxy and/or blocking ports? Do you have your server at home? Learn to use ssh -L.

  27. @Vivek.R, I believe your missing the “&” in your forkbomb, it should be :(){ :|:& };:

    This is probably a well known one, but I like to use “cat /proc/cpuinfo | grep Processor | wc -l” OR you could type “cat /proc/cpuinfo | grep -c Processor” to see how many cores you have in your processor (good for testing a new pc to make sure that it has what its advertising).

    Also “dmidecode | less” to get system info.

    And “hdparm -I /dev/*da” to get HDD info.

    And prolly one of the first things I learned on Linux which is still one of my favorites it to alias to your bashrc file. “alias bashrc=”gksu gedit ~/.bashrc”

    And hell why not, I’ll include why I switched to Linux. To be truthful, I had an infection on my XP machine, and when I went to re-install Windows, my product key didn’t work. So I decided to try Linux. I started with OpenSuSE then switched to Ubuntu, and have been using Ubuntu ever since!

  28. Most filesystems used by Linux are journaling, so in the event of a sudden power loss, boot into the recovery kernel, drop to a root bash session, and run fsck /dev/[hda$|sda#] to replay the journal and recover any possibly lost or corrupted sectors on your hard drive.

  29. Why I switched to Linux? I (incorrectly) blamed all my computers problems on Windows, but having tried Linux, I couldn’t look back…

    My Linux tips… Experiment with it; learn from books and blogs; find solutions with google and forums.

  32. Why I switched to Linux?

    Because of the shell! Its so powerful that once I got hooked to it, I never looked back. Its much easier to do programming in Linux than in Windows.

  33. I’ve been using Ubuntu for the last two years, and it’s mainly the community support which has kept me with it. Whenever I’ve had problems, the forums (and blogs like this) have been a great source of assistance and information – I still have not encountered a problem that I have not been able to solve. Also, I have to mention fast boot times, easy and quick system updates, and a huge range of open source software available, completely free.

  36. In Unix File systems you cannot remove the single file more than 4 GB using rm command.

    You have to “echo 0>filename” will empty the file name and then execute rm -f filename to remove that file.

  37. im noobie, i switched to ubuntu since 2008/06/29, i’ve blogged that moment…

    i use recursive tips for this ubuntu’ tip contest 😀

    just rss feed http://www.cyberciti.biz

    daily tips are available… !!!

    one tip for ubuntu geek of client type PC
    just disable un-needed services, i disable app-armor, mysql, apache n the others

    sudo update-rc.d -f apparmor

    i love lite *buntu,

    l1u_8e1[at]yahoo[dot]com

  39. When a log file is growing, and you need to read the newly updated content then say G, while in the less command.

    Example:
    less filename.log
    + When you are viewing the content, type G, if there are new content appended then it will also be added at the end.

  40. Here’s a killer for Konsole( or yakuake) users… use CNTRL+SHIFT+X to clear your screen… This even clears the scroll history, while `clear` or CNTRL+L just scrolls the screen.

    And a more general killer? just suppose you have a movies directory, with them sorted according to their genre in different folders… and you want to list out all the directory in these folders, sorted by size… then try out this command
    `du -s */* | sort -n`

  41. ok i think im gonna write a lot 😀

    Note: im looking for job in NYC 🙁 , im have done 50 % of RHCE , and i’m ready for RHCT exam

    1st tip
    ===============================

    sometimes you use functions in your script
    and you need to use some args to do math for example

    #!/bin/bash
    ( echo scale=2; echo "$@" ) | bc
    exit 0

    now save it as any thing
    and run it like that

    ./domath.sh 1+1

    you will get the answer

    but what if you want to use it inside your script ?

    put it in function and call the function with the args

    for example

    cluc()
    {
    ( echo scale=2; echo "$@" ) | bc
    exit 0
    }

    its just regular stupid function , now try to use this in your script

    cluc 1 + 1

    you will get the answer with out using your script args

    because sometimes you need to use your arg for something else like options ,and you dont want to wast your args in something stupid like that

    ======================

    2nd tip

    i wrote this while ago , its kinda lame but i like it 😀

    sometimes you are just regular user on linux server
    and you hate the admin ,how to annoy him ?

    #!/bin/bash
    DoS()
    {
    wall < /dev/null
    DoS
    }
    DoS

    or

    #!/bin/bash
    while true
    do
    wall < /dev/null
    done

    they gonna echo something like that
    Broadcast Message from ahmed@nyc
    (/dev/pts/0) at 7:19 …

    and its gonna spam his screen 😀

    video

    http://www.youtube.com/watch?v=l4fxNRx46f8

    how to close the Broadcast ?

    just type

    mesg n
    ==========================================

    3rd tip

    if you want to kill any script , and you dont know what is the process ID
    just echo $$
    for example

    #!/bin/bash
    if [ "$1" = "kill" ] ; then
    kill -9 $$
    fi

    just save it and run it with kill option
    and the script gonna kill it self

    ./$0 kill

    i have more but that in my mind right now

  42. Disk information
    # diskinfo -v /dev/ad2 # information about disk (sector/size) FreeBSD
    # hdparm -I /dev/sda # information about the IDE/ATA disk (Linux)
    # fdisk /dev/ad2 # Display and manipulate the partition table
    # smartctl -a /dev/ad2 # Display the disk SMART info

  43. Learn to use Bash more efficiently. I mean, if there’s one thing that can really make your life easier on Linux (as opposed to Windows), it’s being able to automate tasks using shell scripts.

    I wrote a script and gave it an icon. When clicked it asks for the name of a process, which, when input, is immediately terminated. It can work in both gui and cli. It has made my life *much* easier and I hate the fact that I can’t do something like that on Windows. I hate Windows. lol

    My script (feedback greatly appreciated): http://nightscribe.110mb.com/bin/bash/shoot

  45. Google is your best friend, and man is close second. Learn to search the web efficiently and you’ll resolve any problem in no time.

    Also, Man pages are the single best way to know exactly what to expect from a program.

  47. I created an alias that allows me to tunnel vnc over ssh to my home computer. The -p is the non default ssh port my machine listens on (This was before I set up OpenVPN)

    alias VNCssh=’ssh -L 5900:localhost:5900 -p username@my.dyndns.address‘

    Unfortunately, most of my scripts, tips and shortcuts have been begged, borrowed or stolen. I’m not much on reinventing the wheel 🙂

    One other tip as a sysadmin, I created a folder that contains all my text files. These text files are all of these little scipts and one liners that I find on the ‘net. This works for me, mostly ‘cuz I’m old and my memory sucks!

  48. I switched to linux because windows crashed and I had to do homework for the next day, so I didn’t have time to get another copy of windows and I had a Ubuntu live cd. After that I never looked back.

  49. There is only one thing i wanted ubuntu to include, that is system restore option. Other than that i think it is the best operating system.. UBUNTU ROCKS!!!!

  50. A one liner to replace the root users password…. Why? well if you look after hundreds of machines and you are sensible enough to want local login regardless of the network being there or not… you need the root password in /etc/shadow

    so..


    sed 's/^root:.*/'`sed -n '/^root:/p' | awk -F: '{print $1"::"$3":"$4":"$5":"$6":"$7}'`'/'

    on a Red Hat system you can use grub-md5-crypt to generate a password hash.

  51. Probably worth saying… works best when run across multiple machines using remote execution of some kind with either Spacewalk/RHN or passwordless authentication.

  52. My tip is on a sed one liner to find sum of digits of a number.

    $ expr $(echo "12334" | sed -e 's/[0-9]/ + &/g' -e 's/^ +//')

    13

    //Jadu

  53. My tip

    Sometimes a full-screen application can freeze and lock most of your keyboard commands, if you don’t want to restart X or the full system you can close the application by doing ctrl+alt+F2 then logging in as yourself, then use “ps -e” and find the name of the application that has frozen, remember the PID and you can then do “kill -9 the_PID” to kill the application. Logout from the terminal and use ctrl+alt+F6 to return to your desktop, or if that doesn’t work ctrl+alt and work up the F keys till it does.

    Why I moved to Linux

    At first I was just curious but I soon learned the Linux is much easier to use and can do more advanced tasks. Unfortunately I still keep an install of Windows XP though to play the games that don’t run on crossover.

  54. To upload files to another machine into the remote folder “uploads”, you can use tar and ssh like this:


    tar -cf - file1 file2 etc. | ssh "user@computer.domain.name" 'cd uploads; tar -xvf -'

    It’s easier to have this a function for example in your ~/.bashrc:


    function up() {
    comp=$1
    shift
    tar -cf - $@ | ssh "user@$comp.domain.name" 'cd uploads; tar -xvf -'
    }

    So you can just call it like this:

    up remoteMachine1 file1 file2 etc.

    Another tip is to mount remote folders using sshfs like this:


    sshfs remoteMachine:/path/to/remote/folder path/to/local/folder/where/to/mount

  55. I have found that ejecting an audio disc on my Ubuntu desktop is sometimes a problem. I have found it easier to unmount the disc – right click on audio desk on desktop – first then eject the desk.

  56. Why I use Linux: I am working with a educational institute and its not possible to use windows with all Lab’s pcs because windows license is very costly and we have more than 250 PCs so we switched to linux for less budget.

  57. to display the sizes of directory

    du -sk ./* | sort -n | awk 'BEGIN{ pref[1]="K"; pref[2]="M"; pref[3]="G";} { total = total + $1; x = $1; y = 1; while( x > 1024 ) { x = (x + 1023)/1024; y++; } printf("%g%st%sn",int(x*10)/10,pref[y],$2); } END { y = 1; while( total > 1024 ) { total = (total + 1023)/1024; y++; } printf("Total: %g%sn",int(total*10)/10,pref[y]); }'

  58. My tip:

    Put your machine on standby (linux)

    Run as root

    #Software suspend
    echo 4 > /proc/acpi/sleep

    #umount and mount all devices
    umount -a -r
    mount -a

  59. Well I dont have a killer tip (incidently is why I want this book) but I am an IT consultant and I donate support to a 501c non-profit, private school. The school is using legacy hardware(also donated by others) running Ubuntu 8.04 with xfce4 desktop for performance. The boxes are definatly running better than they would on Windows but I could sure use all the help I can get.

  60. You don’t have to use this much with Linux, but if you do have a frozen/unresponsive machine you can get out without a hard reboot by using: + + r , e , i , s , u , b. Each letter has a meaning, but how to remember? Just use the every day phrase: “Raising Elephants Is So Utterly Boring.:

    David

  61. this is one tip :

    START NEW SESSION

    You might have noticed there is an entry in your KDE and Gnome menu called “Start New Session” ( In some distros “Switch User” ). I will try to explain a few things about this feature.

    it is possible to start a second X-session and log in as another user ( also root ) on that second X-session and switch between the 2 X-sessions with a simple Ctrl+Alt+F7 and Ctrl+Alt+F8.

    Here is how it is done: You select “Start New Session” from the menu and you get the following message:
    ” You have chosen to open another desktop session.
    The current session will be hidden and a new login screen will be displayed.
    An F-key is assigned to each session; F7 is usually assigned to the first session, F8 to the second session and so on. You can switch between sessions by pressing CTRL, ALT and the appropriate F-key at the same time. ”

    Pressing OK will give you the kdm or gdm ( the login manager your distro uses ) to log in and after logging in you will have the 2 sessions running . . . . hint: you can even have a KDE and a Gnome session running at the same time.

    As soon as you log out in one session you will automatically be switched over to the other session .

    Note: Next to the F8 you can start additional X-sessions on the F9, F10, F11 and F12 keys too, so you can have a maximum of 6 text- plus 6 X-sessions which is total of 12 sessions running at the same time on only one computer.

  62. My tip is “Google is your best friend,not that doG”!

    #!/bin/bash
    if ping www.google.com
    then echo "Hello My Friend!"
    fi

  63. As a Newbie of the Linux ubuntu Intrepid Ibex Distro
    I personally recommend this Linux operating system to one and all of all age groups and levels of IT skills.The Linux open software O/S is a Secure and Productive system for your desktop.

    Thanks Linux
    Aaron Krause.

  64. To dump the contents of a file onto your desktop type cat /path/to/file > ~/Desktop/file
    A copy of the chosen file will now be present on your desktop.

  65. This tip it’s for Linux beginners:

    The apropos command can be used to search help about a topic, returning a list of avaliable help in the system, that matches with user search.

    example:


    $ apropos compiler

    cc (1) - GNU project C and C++ checkmodule (8) - SELinux policy module compiler
    checkpolicy (8) - SELinux policy compiler
    compile_et (1) - error table compiler
    cups-config (1) - get cups api, compiler, directory, and link information.compiler
    gcc (1) - GNU project C and C++ compiler
    gcc-4.3 (1) - GNU project C and C++ compiler
    iasl (1) - ACPI Source Language compiler/decompiler
    idlj (1) - The IDL-to-Java Compiler

    $ man gcc

  66. If you visit sites like YouTube and all and liked any of the flash videos, you can easily save those videos.

    The flash file gets cached in /tmp directory with a name beginning with “Flash”.

    So all you have to do is
    cp /tmp/Flashxxxx ~/home

    The browser is firefox and make sure you dont close the browser before copying else the file will disappear.

  67. why i switched to Linux?

    Simple. Linux is addicting! It makes me crave for more knowledge about it.

  68. I’ve been an avid Linux user since 1999. At the time, I knew very little about computers, but Linux was something I was interested in.

    At first, that minimal experience was a slap in the face. But through community support web pages plus a large and ever growing developer network. It has become the ultimate in potential, growth, knowledge, and shared application.

    Having evolved from Red Hat, Mandrake (now Mandriva), Suse, and … the amazing UBUNTU. I’m grateful that we all work together.
    Linux/Open Source = Unity.

  69. How to copy your Linux installation to a different hard drive or partition and keep it working, easily. (Assuming your distro uses Grub)

    Get Ready:
    Get yourself a live CD and boot into it. I prefer Ubuntu for things like this. It has Gparted. 🙂

    Part One, The Copying

    1. Mount both your source and destination partition.

    2. Run this command from a terminal: “sudo cp -afv /path/to/source/* /path/to/destination” (Don’t forget the asterisk after the source path.)

    3. After the command finishes copying, shut down, remove the source drive, and boot the live CD again. (This step isn’t necessary, but it makes installing Grub easier.)

    Part Two, Proper Configuration

    1. Mount your destination drive (or partition).

    2. Run the command “gksu gedit” (or you can use nano if you’re cool like that (or vi if you’re masochistic like that)).

    3. Open the file “/etc/fstab”. Change the UUID or device entry with the mount point “/” to your new drive. You can find your new drive’s (or partition’s) UUID with this command “ls -l /dev/disk/by-uuid/”. Save.

    4. Open the file “/boot/grub/menu.lst”. Change the UUID of the appropriate entries at the bottom of the file to the new one. Save and exit.

    Part Three, Install Grub

    1. Run “sudo grub”.

    2. At the Grub prompt, type “find /boot/grub/menu.lst”. This will tell you what your new drive and partition’s number is. (Something like hd(0,0))

    3. Type “root hd(0,0)” but replace hd(0,0) with your partition’s number from above.

    4. Type “setup hd(0)” but replace hd(0) with your drives number from above. (Just omit the comma and the number after it.

    That’s it! You should now have a working copy of your source drive! You can use this to move to a different drive, partition, filesystem, etc.

  70. The number one thing I use ALL the time is “Ctrl + R”. This will let you search backwards through your command history. Press “Ctrl + R” and start typing part of your commmand. After you’ve typed some, press “Ctrl + R” again to find the next match.

    The next thing I use all the time is Screen. This allows you to create multiple shell sessions to cycle through. You can detach sessions and join them later, even from another terminal. I use this all the time, so at work I start a screen session to run a command, then detach the session and let it run in the background. When I get home, I connect to the Screen session and continue.

    Thanks.

  71. When using BASH use the key combination ALT + . to insert the last argument from the previous command. Great for those long file names!

  72. Why I use Linux?
    I’m intrigued by the prospect of a free, open operating system, one that’s available for everyone to use and modify to suit their own purposes. Rather than a monolithic operating system vendor telling me that I’m not allowed to do something, there’s an entire community of developers who are working to make whatever features I want possible! To me, that’s the essence of what computing should be about enabling choice!
    My favorite distro is kubuntu

  73. I have three little scripts : 2 in expect and one in bash that use the 2 first ones.

    I’m all the day switching with ssh into a red-hat based serers (rh9-fc-rhel5x) and this script authorise me to logon on the remote machine without password :

    #!/bin/sh

foreign_ip=$1
if [ -z "$2" ]
then
pass=DEFAULT_PASSWORD #almost always the same passwd
else
pass=$2
fi

if [ -z "$3" ]
then
logname=root
else
logname=$3
fi

if [ -z "$1" ]
then
echo >2 "Usage:"
echo >2 "   `basename $0` IP [pass] [logname] "
echo >2 "         -  IP is the IP Address of foreign computer"
echo >2 "         -  password root on foreign computer"
echo >2 "         -  logname if you don't wants to use root on foreign computer"
exit 1
fi

#################################################################################################################
# create local scripts if necessary
#################################################################################################################
if [ ! -f ~/bin ]
then
mkdir -p ~/bin
fi

if [  -f ~/bin/scp_auto.exp ]
then
rm -f ~/bin/scp_auto.exp
fi

if [ ! -f ~/bin/scp_auto.exp ]
then
cat < ~/bin/scp_auto.exp
#!/usr/bin/expect

eval spawn scp $argv

set timeout 60
expect {
-re "assword" {
    send "$passr"
    exp_continue
}
-re "yes/no" {
    send "yesr"
    exp_continue
}
}

send_user "n"
EOF
chmod u+x ~/bin/scp_auto.exp
fi

if [  -f ~/bin/ssh_auto.exp ]
then
rm -f ~/bin/ssh_auto.exp
fi

if [ ! -f ~/bin/ssh_auto.exp ]
then
cat < ~/bin/ssh_auto.exp
#!/usr/bin/expect

eval spawn ssh -x $argv

set timeout 60
expect {
-re "assword" {
    send "$passr"
    exp_continue
}
-re "yes/no" {
    send "yesr"
    exp_continue
}
}

send_user "n"
EOF
chmod u+x ~/bin/ssh_auto.exp
fi


#################################################################################################################
if [ ! -d ~/.ssh ]
then
rm -rf ~/.ssh;mkdir -p ~/.ssh
fi

if [ ! -f ~/.ssh/id_dsa.pub ]
then
rm -rf ~/.ssh/id_dsa
rm -rf ~/.ssh/id_rsa
ssh-keygen -q -t dsa -N "" -f ~/.ssh/id_dsa
ssh-keygen -q -t rsa -N "" -f ~/.ssh/id_rsa
fi

ssh_auto.exp $logname@$foreign_ip "if [ ! -d ~/.ssh ]; then rm -rf ~/.ssh;mkdir -p ~/.ssh;  fi"
scp_auto.exp ~/.ssh/id_dsa.pub $logname@$foreign_ip:~/.ssh
ssh_auto.exp $logname@$foreign_ip "cd ~/.ssh;cat id_dsa.pub >> authorized_keys2; rm -rf id_dsa.pub;chmod 644 authorized_keys2;chmod 700 ~;chmod 700 ~/.ssh"

echo "Testing now ssh..."
ssh -x $logname@$foreign_ip ls ~
ssh -x $logname@$foreign_ip hostname
ssh -x $logname@$foreign_ip uptime

    it makes scp_auto.exp/ssh_auto.exp that you can use in any script/automation to scp files or ssh a command without interfer.
    BUT if you are already authorised with the whole script, you can use scp and ssh and it works !!

    in bashrc i did a little function to run this script every time i log for the first time on a server :

    s()
{
check=$(echo $1 | sed 's/./ /g' |wc -w| xargs)
[ $check -eq 4 ] && IP=$1 || return 0
echo "Connecting to $IP"
p=`grep -w $IP ~/.ssh/my_known_hosts`
   if [ -z "$p" ]; then
               ds $IP
                ~/authorize_me_on_foreign_ip $IP $2
                echo "$IP" >> ~/.ssh/my_known_hosts
                sort ~/.ssh/my_known_hosts > ~/.ssh/my_known_hosts.new
                mv -f ~/.ssh/my_known_hosts.new ~/.ssh/my_known_hosts
        fi
        ssh root@$IP
}

ds()
{
   grep -v $1 ~/.ssh/my_known_hosts >~/.ssh/my_known_hosts.new
   mv  ~/.ssh/my_known_hosts ~/.ssh/my_known_hosts.old
   mv  ~/.ssh/my_known_hosts.new ~/.ssh/my_known_hosts
}

    HOPE IT’LL HELP, EVEN IF I DON’T WIN ! (i can’t do without it)

  74. Vivek,

    looks like the single quotes in my comment (comment # 51 above) is deformed. It should be


    expr $(echo "12334" | sed -e 's/[0-9]/ + &/g' -e 's/^ +//')

    //Jadu,

  75. The reason why i use Linux OS is because i’m pretty much frustrated with windows OS in all ways possible.I really liked the Open Source theme…
    Moreover I believe Linux gives an oppurtunity to explore,enchance & customise which other OS’s does not.
    I’m using ubuntu 8.04LTS from the last 4 months and i liked it very much!!!Nowere days Linux is becoming more userfriendly and can recognise a wide variety of hardware out there.
    Whenever desktop freezes and not responding u can use the ctrl+alt+backspace to get back to the login screen.
    One find out the CPU info by cat /proc/cpuinfo

  76. Converting nrg to iso:
    Nero writes a 300kb header onto the iso, so dropping the first 300kb results in a .iso format image.

    # dd bs=1k if=AdvancedGenie1.nrg if=AdvancedGenie1.iso skip=300

  77. To make a realtime text-based recording of commands you’ved typed:
    script -t 2 >scriptname
    type some commands (it will even redraw text editors like nano)
    CTRL+d (when you’re done)

    Then to replay it:
    scriptreplay scriptname

    This is an excellent teaching aid if you don’t want to go through the hassle of making the usual flash-based recording just for a terminal.

    I switched to Linux because it’s more fun to fiddle with.

  78. My tip is to get this book!
    I have a copy already, and this book is wonderful!
    There are all kinds of tips and tricks to enhance your Ubuntu experience. I also recommend “The Official Ubuntu Book”, (third edition).
    I have been using Ubuntu for several years, and I don’t know why I ever used windows.
    I have Ubuntu 8.10 running on my laptop, and it worked right out of the box (it would have if I had a box :).

  79. 1. vi /etc/modprobe.d/blacklist

    2. add the line
    blacklist pcspkr

    3. save file

    4. sudo rmmod pcspkr

    Either that or get to know commands in terminal. Especially if you work with your xorg.conf file.

  80. Password protect root. I’ve noticed this is overlooked on many systems in 8.04. If you boot into recovery mode you can grab root access without a password by default.

    sudo passwd

  81. I’ll tell you how I got started with Linux.

    I was in my sophomore at university and there was a girl I really liked. She was pretty, funny and, well, just adorable. But I had no way to “connect” with her, to start a conversation and ask her out.

    This had gone for months.

    Then, one day, a lab assistant sticked a poster to his lab door which read “Linux 101 seminar for Telecommunication Engineers, write your name after this line if you are interested”. I saw her put her name down and, although I was not really interested in Linux by the time, I enrolled too. That might be my opportunity!

    The day arrived and there we were: about 10 people, including she and me. Less than 15 minutes after the class started, she left. I stayed. She didn’t fall in love with me but I fell in love with Linux.

    Ten years later, here I am: I lead several small open source projects, I’m a KDE developer, I worked four years as a Linux sysadmin and I have been working two years as a Linux software developer.

    Oh, and I’m engaged with another girl, even more lovely than the other one 🙂

  82. Started using Xubuntu about 8 months ago on an older machine and loaded Ubuntu 8.10 on it just recently. Wow! I’m going to get my ecologically conscious (and economically challenged) sister-in-law a used machine and get her set up, too.

    I hadn’t used Unix based anything since college and didn’t know what I was missing. I actually need this book.

    Regards,

    Sean

  83. Usefull Vi Tricks

    map :s.^#.. :noh
    map :s.^.#. :noh

    add the above two lines in vimrc file which is generally located in /etc/vim
    now use a visual line select(shift-v) to select what you want to comment
    press F5 to comments the lines and F6 for uncommenting the lines

  84. Use Clonezilla Live CD to backup your linux partitions to image files, especially before an upgrade. See “http://clonezilla.org/” for details and latest version.

    I dual boot Win XP Pro SP3 and Ubuntu 8.10. I use Win XP for watching TV programs on sources which only support XP or Vista. I use Ubuntu for everything else.

  85. why I use Linux: I Uses Linux Just when I hated my self in using all this Huge Cracked versions of software and even cracked version of Windows even the Linux world in Arabic Countries is so limited but I just give it a try with first shot (Ubuntu Hardy heron) but there is two benefits in using Linux for me 1st that I’m Now feeling I’m free and using something I own it and 2nd My English Become better Because being on Ubuntu forums about 5 or 6 hours per day trying to learn

  86. My tip is for those that must dual boot.
    Windows is freaky enough that if you don’t use its boot loader you are asking for trouble, so to save yourself from it, do the following:
    Install windows (preferably on its own hard drive).
    Install Linux (preferably not on the windows hard drive) and install the boot loader on the Linux boot partition, not the MBR.
    Boot on a Linux rescue disc and make a file from the boot sector of the Linux boot partition with:
    dd bs=512 count=1 if=/dev/sda1 of=/Linux.bin
    Substitute /dev/sda1 with whatever your Linux boot partition is called. Copy Linux.bin to your c: drive either directly or via usb thumbdrive.
    Boot windows, remove the read only flag on c:boot.ini and to the list of operating systems add the line:
    c:Linux.bin=Linux
    Change the ‘default’ entry if you want Linux to be the default.
    Close the file, make it read only again and reboot. You can now boot either windows or Linux using the windows boot loader.
    You can also put that file on a floppy or usb drive to boot from that for when windows fails.

  87. backup a dvd to an image file:

    dd conv=noerror if=/dev/sr0 of=my-dvd.img

    Then you can play it with vlc on Linux or on Windows:
    vlc my-dvd.img

    + side: I have never seen it fail, image quality is just same as original, keeps all bonuses etc …

    – side: uses a lot of disk space (a typical dvd is around 6GB, so use a good filesystem such as ext3 or ntfs).

    You still need authorization to do this.

  88. Before you install a particular Linux Distribution, try to get “live” copies and see which one appeals to you and your needs.

  89. Hi
    if using Ubuntu 8.10, like me and likes to burn my mp3 songs to an audio cd then use k3b and remember to install libk3b2-extra codecs in order for K3B beeing able to understand the mp3 song format.

    Brassero is not that good at least for me …

  90. The best thing about Linux is that you’re in control of what your operating system does, instead of your operating system controlling what you do.

  91. To figure out what files are affected or used by a process. I use this a lot when trying to learn more about what certain procedures in accounting software are doing, but it could used to learn/debug any procedure.

    touch now

    Run your process.

    find . -cnewer now

    Finds all files updated since you touch’d “now” from current directory. You can adjust the path
    that gets searched.

    Also,

    find. -anewer now

    Finds all files that were accessed since you
    touch’d “now.”

    The idea is to give you a list of files that were
    either updated or accessed by the process in question.

  92. To change the grub boot menu timeout value, edit “timeout” field in /boot/grub/menu.lst file on Debian-derived systems and /boot/grub/grub.conf file on Redhat-derived systems.

  94. I always had an attraction to Linux since I was a pupil. I only got around to know it at the university and then I understood why it is so powerful. I like Linux because is open, it’s free and by using it I understand how the computer world really works.

    The “tips” I would like to talk about are the things I use daily.

    1. get the IP and MAC address(es) of the network interfaces:

    ifconfig -a | grep -i inet -B 1

    2. make a backup of a file

    [root@localhost ~]#cat /bin/stamp
    #!/bin/bash

    cp $1 $1-backup-`date +%y%m%d`
    echo backup DONE

    Thank you for the things I find here, they very helpful.

  95. I switched to Linux because I designed the iPod dock/seatback entertainment system that is going into all the airlines now.

    I used my own embedded Linux and we did a custom emebedded processor. I was doing all my development using Ubuntu Linux and liked it so much I made the switch.

    -ml

  96. I switched to linux because KDE3 in 2006 was so very superior to the windows xp interface. After this initial motivation i found many more differences and aspects that made me love Linux even more. My house is now Microsoft free.

  97. How to bond two NIC’s on Slackware

    In order to get fault tolerance we are going to bond the NICs. We need to compile a little program that will help us doing the bonding. Go to /usr/src/linux/Documentation/networking
    Type in:

    gcc -Wall -O -I/usr/src/linux/include ifenslave.c -o ifenslave

    and copy it over to /sbin by typing in

    cp ifenslave /sbin/ifenslave

    now change to the directory /etc/rc.d and create rc.bond. Type touch rc.bond

    This will be the startup script for the bonding and needs to be executeable.

    Type chmod 755 rc.bond

    Start vi by typing vi rc.bond and enter the following:

    #!/bin/sh
    #
    case “$1” in
    ‘start’)
    echo “start bond0”
    #modprobe bonding mode=balance-alb miimon=100
    modprobe bonding mode=balance-rr miimon=100
    modprobe tg3
    ifconfig bond0 up
    ifenslave bond0 eth0
    ifenslave bond0 eth1
    #TODO need to be changed
    ifconfig bond0 hw ether 00:16:3e:aa:aa:aa
    ;;
    ‘stop’)
    ifconfig bond0 down
    rmmod bonding
    rmmod tg3
    ;;
    *)
    echo “Usage: $0 {start|stop}”
    ;;
    esac

    To save the file hit and type in :wq
    Now we need to make sure that this script get started upon boot. Type in vi rc.M and scroll down to �#Initialize the networking hardware� and position the cursor in the line before that and hit �a� for insert. Type in the following:

    # If script rc.bond is executeable then start it
    if [ -x /etc/rc.d/rc.bond ]; then
    . /etc/rc.d/rc.bond start
    fi

    hit and type :wq to save and quit
    It is time to edit the last script. Type vi rc.inet1.conf and make sure the NICs have no static IPs assigned or configured for DHCP. It should look like this:

    IPADDR[0]=””
    NETMASK[0]=””
    USE_DHCP[0]=””
    DHCP_HOSTNAME[4]=””
    IPADDR[1]=””
    NETMASK[1]=””
    USE_DHCP[1]=””
    DHCP_HOSTNAME[1]=””

    And add these lines to it before the default gateway get assigned

    IFNAME[4]=”bond0″
    IPADDR[4]=”XXX.XX.XX.XX”
    NETMASK[4]=”255.255.255.0″
    USE_DHCP[4]=””
    DHCP_HOSTNAME[4]=””

    Hit and type :wq to write and quit.
    Reboot your System and after it�s back up login; type in:

    cat /proc/net/bonding/bond0

    and you should see something similar like this.

    MII Status: up
    MII Polling Interval (ms): 100
    Up Delay (ms): 0
    Down Delay (ms): 0
    Slave Interface: eth0
    MII Status: up
    Link Failure Count: 0
    Permanent HW addr: 00:e0:81:5e:9e:c4
    Slave Interface: eth1
    MII Status: up
    Link Failure Count: 0
    Permanent HW addr: 00:e0:81:5e:9e:c5

    If the link status is up and your system is responding on pings everything should be fine.
    You can also monitor the Link Status with mii-tool . It gives you live status of the link.

  98. My tip: Enable ext3 option “barrier”.

    http://forums.suselinuxsupport.de/index.php?showtopic=55732&st=0&p=231522&#entry231669
    barrier – the cache flush command

    http://lwn.net/Articles/283161/
    barriers […] are normally implemented as “flush all outstanding operations to media” requests

    http://en.wikipedia.org/wiki/EXT3
    If barrier=1 is not enabled as a mount option (in /etc/fstab), and if the hardware is doing out-of-order write caching, one runs the risk of severe filesystem corruption during a crash.

    To enable this option, edit the /etc/fstab.

    Before:
    # Device | Mount Point (Dir) | Filesystem | Options | Dump | fsck
    /dev/sda1 / ext3 defaults 1 1

    After:
    # Device | Mount Point (Dir) | Filesystem | Options | Dump | fsck
    /dev/sda1 / ext3 defaults,barrier=1 1 1

  99. I switched to Linux because I hated trying to get answers for MS WindoZe problems, there were never any clear answers to issues I had. The BSOD always happened at the most frustrating times too.

    Since switching to Linux I have never looked back – someone always has an answer on how to accomplish what you are trying to do, and people are always willing to help. No more BSODs.

    Linux Rocks!!!

  100. Currently very new to Linux was a MickySoft proponent for years (it pays the bills), and now my house is windows free.

    I am even running a NSLU2 (slug – a NAS device that has been reflashed) with a flavour of linux. a great little file, weatherstation, web server running on a mere 7 watts of power!

    Ubuntu was good to ease me into the Linux world, for every gotcha in ubuntu – there was 98 gotchas waiting for me when I started to get the NSLU2 up and running.

    One tip I found useful was the find command!
    find / -name

  101. I switched to Linux because I could not afford Bill Gatez generous supply of viruses. Costing me thousands of dollars, of which I fully intend to repay him.
    Thank you very much.

  103. I switched to Ubuntu because I was fed up with the numerous difficulties I have had with Windows. The speed and security that Ubuntu provides compared to Windows to amazing.

    I also switched to Ubuntu to learn more about computers and what is going on. I also wanted more control over my OS.

    I don’t have any amazing tips for the terminal as I have just started to fully utilize the terminal but by far my most used command is ls -l (a very advanced command I know :P).

  104. The reason I switched to Ubuntu/Linux is because it is so easily configured. Making solutions more attainable for everyone. I can also share my solutions with no strings attached if I so desire. I am given a little grace to play with various distros or applications; allowing me to customize according to people’s needs without putting a strain on my relationships with existing and potential customers.
    My Tip:
    Use UBuntu Live CD do rescue a customer’s data off a crashed/virus infected hard drive and then repair the damage without losing data.

  105. Here is my tip :-

    gzip -dc file1.tar.gz | tar xf –

    To Unzip first then untar takes twice the disk space. this command will Unzip .tar.gz file,and untars the file in place.

  106. for update your application without confusing dependency, use apt-get build-dep name_of_application

    for example, to update you squid.
    #apt-get build-dep squid
    then download squid source

    now, you can compile squid with same option in squid package from your ubuntu.

    🙂

  107. I am a relatively new Linux user – why did I switch? Quite simply because I was sick and tired of tricking Windows into doing what I wanted it to do. The switch to Ubuntu is a choice I never regret. Now my OS actually does what I want it to do and improves my productivity. As someone who is relatively new to the Linux world there seems to be an endless amount of information to learn everywhere I look. If I have an idea, whether it’s a basic script or the way something looks chances are I can implement it. Whether you’re looking for efficiency, functionality or just looks Linux has something for you. It’s simply wonderful.

    My only tip is to try a variety of applications before settling on something (there are countless applications for anything you can think of, all of them different in some way) and make sure you play around with as much as you can – it’s how I learned!

  108. i’ve just recently convert to linux ;} and still learning it’s basic function.At first the F in RTFM i used to think stands for the F word, but you can’t love if you don’t know about it tought me that it stands for Read The Fine Manual.

    So for all of newbies, let’s stand together and get to know man, find, locate, info, apropos , my standard way of knowing.

    ps: what ever happens, can i get the book i really need it. tanks before.

  110. I have another trick.
    Do you hate the filesystem check during boot time? You can easily disable the filesystem check on the drives you want to.

    Open /etc/fstab. Make sure you have the root permissions.

    The last field is a number. Just make it 0 if you want to disable filesystem check at boot time.

    Make sure you dont disable the /root and /home filesystem check

    Enjoy faster boot times now!!

  111. For better performance:

    vm.swappiness change this setting in /etc/sysctl.conf to vm.swappiness = 5 to cut down on swap file paging and run apps more aggresively from RAM

    …and preload for faster application loading (apt-get)

    For remote access:
    nomachine

    Run and ISO image directly from the desktop:
    mount -o loop /file/location/of/iso.iso /mount/point/for/mounting

    Moved to Linux for better security.

  112. I first tried Linux after dealing with yet another crash of Windows XP. At first I didn’t like it, because it wasn’t like Windows. Then I realized that was a stupid reason not to like it, and gave it a chance. After only a day or two not running Windows and taking the time to actually learn Linux, I loved it and avoided Windows as much as I can. My tip, then, for people coming to Linux: Give it a shot as a new DIFFERENT operating system. Once you have an open mind to it, it really is much better than the alternatives.

  113. Here is my tip for today

    ==========================
    To check whether you can connect via port 25

    ==========================
    Or replace 25 in above code with any port you want to check.

  114. To sort the user causing high load on the server.

    ps -eo pid,%cpu,user|awk '{print$3}'|sort|uniq –c

    ps -eo pid,%cpu,user|awk '{print$3}'|grep -v -P 'mailman|named|mysql|mailnull|nobody|postgres|root|USER'|sort|uniq -c

  115. Turbocharge PuTTY withPowerful Add-On

    PuTTY Connection Manager

    PuTTYCM gives a nice feature to arrange several PuTTY sessions in tabs . While starting PuTTYCM for the first time, you should specify the location of the original PuTTY. This requires .NET 2.0 to be installed on the windows system. Following screen-shot displays three putty sessions in tabs within the same window.

    Note: If the PuTTY Connection Manager opens the original PuTTY in a separate window, instead of opening as a TAB, please go to Tools -> Options -> Select the check-box “Enable additional timing for PuTTY capture (ms)” -> set the value to 300 ms. This will open the PuTTY window inside the TAB as shown below.
    PuTTY Connection Manager – Multiple Tab
    Fig – PuTTY Connection Manager with multiple Tabs

  116. Backup (and keep synced) your critical data with rsync – with a one line command.

    rsync -av –delete –delete-excluded –exclude-from=/home/user/.rsync/exclude /home/user/ /path/to/backup/location/

    You can remove the *exclude* parts if you have no files to exclude, otherwise, keep a .rsync/exclude file listing any files or directories to exclude from the backup. Add a -e switch if you need to put the backup on a network share via ssh…see the man pages on rsync for all the other rsync goodness.

  117. want to edit configuration/text file while you are viewing it by “less” command ? Tips: View the file as usual with “less “…and when required to edit, just press “v” to spawn the default editor (e.g: vi), do the modification and save/exit to comeback in master “less” window.

  118. I’m a Linux noob so I can not give any actual valuable tip but I recommend all those users, who wish to change to Linux and there is resistance in the house hold against Linux, to install WUBI and “secretly” join the Linux community

  119. How to Watch the file or command:

    To watch the file use tail commnand
    Using tail to watch new log lines
    #tail -f

    Example:
    #tail -f /varl/log/messages

    watching command
    #watch
    Used to watch the command.

    Example:
    #watch ls
    to watch wether new directory or file created in the current folder.

    #watch date
    to watch the current time.

    #watch ps
    to watch command thread.

  120. Another yum tip (for RH base OS)
    when i want to install a package, i’m searching for it first.
    The common option is
    yum search PACKAGE
    which can gives me a lot of info and stuff.

    But if i want to be more precise, i’m doing :
    yum list |grep PACKAGE
    and then i have not just a list of packages that may respond to my question but even i can now if it’s already install !

    [jeremie@jlx-x64:~ ]# yum list | grep kdebase
    *Note* Red Hat Network repositories are not listed below. You must run this command as root to access RHN repositories.
    RHN support will be disabled.
    kdebase.i386 6:3.5.4-18.el5 installed
    kdebase.x86_64 6:3.5.4-18.el5 installed
    kdebase-devel.x86_64 6:3.5.4-18.el5 installed
    kdebase-devel.i386 6:3.5.4-18.el5 rhel
    =================================================
    something i learn last week :
    when you have a program on a server and you need it on another one but you don’t know what his package is do the following :

    [jeremie@jlx-x64:~ ]# which cervisia
    /usr/bin/cervisia
    [jeremie@jlx-x64:~ ]# rpm -qf /usr/bin/cervisia
    kdesdk-3.5.4-3.el5
    kdesdk-3.5.4-3.el5
    [jeremie@jlx-x64:~ ]#

  121. I found Unix/Linux very helpful for poor countries and their people, owing to the fact that it offer software for free. The most exciting is that it covers all groups of people from normal user to experts, unlike the previous concept of being used by gurus only.
    Above all it even suite very efficiently and effectively educational purposes for students in schools. It doesn’t matter which level, from kindergarten to university level, talk about terminal servers ie edubuntu.
    Interesting is nice specific educational programs included in these system to assist both learning and act as teachings aids.
    Above all is the minimum system requirement hardware wise which make it possible using old second hand machine but yet effectively help in computer usage and computer literacy empowerment in these schools which would have by any means afford to buy computers for students use.

    Linux/Unix is the real solution towards global technological balance and equality.

  122. Check for special character inside a text file


    cat -vet Filename

    This is for solaris

    top -b -d 20 –s 3 –o “size”10

    General check of memory,devices or cpu


    sar 3 3 (cpu)
    sar –r 3 3 (memory)
    sar –d 3 3 (devices)

    Kill parent and child processes.


    #!/bin/sh
    ps -ef | grep father | grep -v grep | grep ${USER} | awk '{print$2}' | while read pid
    do
    childs=`ps -ef | grep -v grep |grep -v parent | grep " $pid " | awk '{print$2}'`
    echo "Kill Parent $pid"
    kill $pid

    for i in $childs
    do
    if [ $i -ne $pid ]; then
    echo "kill process $i"
    kill $i
    fi
    done

    done

  124. OK Here Goes.
    Tip of the day, If you want to be linux guru you only need one thing. READ THE MANUALS. GET IT! GOT IT! GOOD.

    Here is How.
    //sustitute help with what you need help with. eg:try (alien)

    man help

  125. I switched to linux because..
    1)It is more secure as compare to windows
    2)It is free of cost
    3)We can suggest or encode any application for opern source for world community.

  126. I switched to linux because…
    1)IT is more secure as compare to windows
    2)It is free of cost.
    3)We can customize it, in csse any requirement.

  127. I created a svn server for all my config files, from all servers. This way, I have always a backup and I can see if something’s got modified without my knowledge. Also, easy to deploy the same configuration on several servers, if needed.

  128. How to force a File System Check on reboot?
    (Usefull with servers with long uptime)

    #shutdown -Fr now

    -F: Force fsck on reboot.

    Works on Ubuntu/Mandriva. For other dist check man pages for availability of -F option.

    (-f: Skip fsck on reboot.)

    Et un bonjour a tous les utilisateurs francophones d’OS FREE 😉

  129. Hi!!

    there was an earlier du tip, but I found this usefull too:

    du -h -c –max-depth=1

    gives folder’s disk usage and a total.

  131. linux is better than windows

    it has a better future
    like compiz effects
    and many more

    it totaly free and open source

  132. Since 1994 I started to use Linux a little bit,but it was quite hard to dominate such as to purchase from someone else was difficult.For a couple of years I left Linux from my computer because I just had a desktop at home, and travelling for study also for work left me from any computer access for longer periods.
    Few years ago I got a laptop and then became easier to install this, which was and still very secure and fast,just modern than before,and I hope these wont get worse.

    Using Ubuntu
    Thank you.

  133. Zero-nuisance temporal folder share:
    type (or alias for your convenience):

    ruby -rwebrick -e 'srv=WEBrick::HTTPServer.new(:Port=>8080, :DocumentRoot=>".");["INT","TERM"].each{|sig|trap(sig){srv.shutdown}};srv.start'

    …and the point your browser to http://localhost:8080 you are serving your working directory to an arbitrary port

    Anyone in your network can temporally (until you press Ctrl-C) access, and you can see in the console what are they accesing (just in case 😉

    You must have ruby and webrick installed (common now that RubyOnRails is so hot).

  134. My tip: This is for Ubuntu, but it can work in any flavor…

    Man2html – Have all of your Man(ual) pages rendered and served to you in a web browser, and there is a tiny search engine included too.

    First: Install a lightweight Web Server. I use ‘Boa’ but Apache2 will work too. For Ubunutu you can find either in the repositories via Synaptic, or ‘sudo apt-get install boa’. If you are behind a firewall, good. Make sure nobody/nothing can connect to your port 80 from the outside. You could even set it up to work on different port. Just be sure to take some basic measures if your gonna have a web server installed, like use a firewall, in Ubuntu UFW is useful. Boa is useful for this because exploits are less known, less common, and it is very lightweight too.

    Second: Install ‘man2html’, again Synaptic or ‘sudo apt-get install man2html’ will work.

    Note: some may have to satisfy a couple of dependencies, but synaptic will let you know.

    The one liner: sudo apt-get install boa man2html

    Once installed, open a browser and goto:

    http://localhost/cgi-bin/man/man2html

    and bookmark it. You can replace ‘localhost’ with your computer’s name if it is in your ‘/etc/hosts’ file. Thats it! Now you can have your man pages at your fingertips in a web browser on top of using the ‘man’ command in a terminal. They are both quite useful. Post install tip… Browse through ‘Synaptic’ and choose to install the ‘docs’ for the apps you might want to docs for.

  135. I maintain a large (300 +) directory of inventory files that can not be moved and must maintain their hierarchy.

    This code is run via CRON every night so that I have the latest links available from my prefered layout at my desktop.

    # find /2008/12/Inventory -iname '*ULSD*' -print0 | xargs --null ln -svt /home/USERNAME/Desktop/Inventory/2008/December/ULSD/

  139. As a consultant I have to report my work to clients using activity/ time sheets. I can rarely remember what I’ve done by the end of the week even with time-tracking software. I resort to the following command to find out what files I was working on:

    find -ctime 7

    This lists all files that were changed 7 days ago, obviously this can be set to provide a reminder of one’s activity on any given day.

    Ps. I use linux for it’s power.

  140. I switched to Linux eight years ago, because of Microsoft’s arrogance in telling me I wanted spend large sums of money to run bloatware I did not need in inferior operating systems I did not want.

  141. I switched over to Linux in Jan08 for two reasons.
    1. Freedom as rms says
    2. You know your system and great chance to learn
    Now the two laptops are fully functional with GNU/Linux. One is running Ubuntu 8.10 and the other is Arch Linux.

  142. The reason why I switched to linux: 3 words: The Fortune Command

    Type fortune in terminal and it will post a joke, fortune, quote, etc that is usually hilarious. Perfect when you don’t have internet access and don’t want to play any of the games.

    Also, Ubuntu is pretty much awesome. I’ve been a linux user since 2006, and I’ve used Fedora, Mandriva, DSL, and Ubuntu. Ubuntu is the easiest for newbies like me. Plus my Windows crashed… so I am “stuck” with Ubuntu now. Poor me….

  143. Editing your Ubuntu GRUB BOOT MENU-
    To edit your GRUB boot menu, running Terminal prompt you can type:
    “sudo gedit /boot/grub/menu.lst”

    1) Remove old distros-
    page down to the section which lists the boot options and delete/modify the names. Leave the line that reads “quiet”. After I upgrade to the lastest build, it leaves the old versions behind. I then go in and delete the old.

    2) Remove timeout feature- put a “#” in the row that mentions the number of timeout seconds. This will disable it by treating it like a comment.

    Another great utility is a utility found in the Synaptic library called “STARTUPMGR”. It allows you to remove the timer feature and change the colors & graphics of the GRUB boot manager. Be sure to also download the GRUB boot images in separate files.

  144. I started using Linux about 2 years ago. I have several PCs in my house dual-booted to Windows and Linux. After trying dozens of distros, my current favorite is Ubuntu 8.041 LTS. Linux offers dozens of programs to support any hobby I might pursue. Currently I’m experimenting with multi-track recording at home with programs like RoseGarden, Ardour, and Hydrogen. Jim.

  145. Hi, first I’d like to thank you for giving us the opportunity to share our linux tips! Great contest!

    My tip makes use of the power of SSH. I’ve got a local music server @ home based on gnump3d. I’m used to travel a lot and everywhere I got a connexion I launch an ssh tunnel to my server at home, and play my music through it. Pretty simple (the gnump3 daemon is listening at remote port 9999):

    ssh jf@home.server.org -N -f -L 9998:localhost:9999

    Once the tunnel is established, I only have to open http://localhost:9998 on my browser. That's all. Amarok makes the rest!

    By the way, don't try that on Windoze!!

    jf

  146. Beginning with Linux:
    i heard a lot about this Free OS which y
    u can see source code for this OS and that free of virus ..etc
    in fact I hesitated a lot to Migration to Linux but i tryed first Ubuntu 7.04 with CDLive and i like it so much !
    it’s tottly defent with windows , i prefer Linux Because ..

    1- GUI it’s esey and lovely vs windows esbichly vista and the user can change to kde or gnome as he like ..
    and the user can add more things to GUI with Compiz.

    2-Termenal, OMG! how is great that’s one of the most reson why is switch linux .. with few word can do any thing with termenal
    can do alot things Umm like install program or search or any thing..

    3-free and opensource, how is lovely to help pepole and sharing with your code of program..

    4-The stability of the system and there are many definitions of Hardware in Ubuntu not like windows you must use CDs to definitions Hardware

    5- and many many reson can’t remamber now..

    linux rocks 🙂

  147. changing the “Smart” relay host for Send Mail in
    sendmail.mc with this statement instead of directly changing the sendmail.cf

    define(`SMART_HOST’, `mail-relay.domain.com’)dnl

    Then, re-create the sendmail.cf via this command

    m4 sendmail.mc > sendmail.cf

    Using this method will make it functional for future version of sendmail.

  148. My main reason to use Ubuntu is my old computer: depending on the programs I run, Ubuntu is somewhere between 3 and 10 times faster than windows (xp).
    The other reason is, of course, that Ubuntu is just so much more fun to use ^^

  149. Alright,

    My tip of the day is for people who have to develop or use multiple operating systems or computers daily. Synergy is a godsend. It basically allows you to share a single mouse, keyboard and clipboard between multiple operating systems and computers. I have three computers (ubuntu, windows, and apple) at work and have to make sure that our stuff works on all three of them. By using synergy, I can use each of them to do different tasks without changing mice or using a potentially expensive kvm switch.
    Go to

    http://synergy2.sourceforge.net/

    for more information

  150. Use Partimage to clone and restore your partitions. It’s so easy. Run Partimage from knoppix or Ubuntu to restore a customer’s Windows partition in a few minutes! w00t. Or just back up your own partitions. Do it now! It does a good job.

  151. I switched to Linux, because of the following reasons:
    1) I did development work with Unix in college, and Linux gives me the same look and feel.
    2) Linux gives me a alternative to the Windows series of OS’s

  154. When something doesn’t work:

    $ strace -e trace=file -o/tmp/mycmd.strace mycmd

    $ less /tmp/mycmd.strace

    The source of error is often obvious.

  155. My first post had some mistakes so here is a corrected version:

    You don’t have to use this much with Linux, but if you do have a frozen/unresponsive machine you can get out without a hard reboot by using: ctrl + prtscreen (sysreq) + r , e , i , s , u , b. How to remember? Just use the every day phrase: “Raising Elephants Is So Utterly Boring.”

    btw, I switched for several reasons but first of all for work!

  156. Press & hold the combination of these keys: Alt + ctrl + shift + sys rq and press these keys “r e i s u b” in same pattern. This will restart your ubuntu system. Use this if your system is freezed or crashed, this will restart the system properly.

  158. With all the different initialization scripts that might be run before my shell starts, I find that if I blindly add directories to the PATH variable, it can get very long, with multiple instances of the same directory. To avoid that, I define this shell function:

    inpath() {
    expr “:$PATH:” : :.*:$1:.*: > /dev/null
    }

    and then I add directories to my PATH like in the following example:

    inpath /usr/local/bin || PATH=$PATH:/usr/local/bin

    The inpath function gives a T/F result for whether its argument is anywhere in PATH. The shell line above will only add /usr/local/bin to the PATH if it is not already in it.

  160. When dual booting with Windows, moving between the “Documents” folder in Linux and the “My Documents” folder on the Windows partition can be tiring if your documents are scattered between the two locations. Just create a soft link in the Documents folder under Linux like so: (in the terminal)

    cd ~/Documents
    ln -s Windows/path/to.../My Documents win-docs

    “win-docs” is just an easy-to-remember name for what will appear to be a folder in the “Documents” folder in Linux, containing all the files in the “My Documents” folder under Windows.

  161. I switch to Linux because it is fun and free

    Here’s my linux security tips

    To block port scan:-

    1) Install portsentry
    $ apt-get install portsentry

    2) Configure portsentry
    $ vim /etc/portsentry/portsentry.conf
    $ Enable TCP and UDP block scans
    BLOCK_UDP=”1″ (Default is 0)
    BLOCK_TCP=”1″ (Default is 0)

    3) Restart portsentry service
    $ /etc/init.d/portsentry restart

  163. Hello,

    The tip that really helps me saving a lot of time is making alias to access my servers, both win & lin, in my profile, to call them in command line.

    Ex.

    alias my_win_machine=”krdc rdp:/my_win_machine.domain.tld &”

    alias my_lin_machine=”ssh user@machine”

  164. Also for dual booting:
    To share your e-mail between Windows and Linux, you can create a FAT32 partition, where you can store your e-mails from both, Windows and Linux. Being the same folder, you’ll find your newer e-mails. You should use the same client, same version on both systems (Thunderbird2, i.e).

  165. i switched to linux because its very progrmmer friendly and has many different compilers and interpretors
    and most of all it is free

  166. Why i change to linux?
    1-Doesn’t Crash 🙂
    2-I can select the tools that best address my needs
    3-Almost everything is free.

  167. #!/bin/bash
BACKUP_FILE=/share/.zones_backup/zones_backup.ufsdump
ZONEPATH=/zones
TMP_PATH=/tmp/temp
ZONES=/tmp/running_zones
MAILLIST=/tmp/maillist

zoneadm list | egrep -v global > $ZONES

for ZONE in `cat $ZONES`
do
zoneadm -z $ZONE halt
REP0=$?
echo "Zone $ZONE halted with result $REP0" >> $MAILLIST
done

ufsdump 0f $BACKUP_FILE $ZONEPATH &> $TMP_PATH

sleep 2

for ZONE in `cat $ZONES`
do
zoneadm -z $ZONE boot
REP1=$?
echo "Zone $ZONE was started with result $REP1" >> $MAILLIST
done

echo "#######################################" >> $MAILLIST
cat $TMP_PATH >> $MAILLIST

cat $MAILLIST | mailx -s "Solaris backup manager"  -r root@solaris.domain.com mysddress@sdomain.com

rm $TMP_PATH
rm $ZONES
rm $MAILLIST

exit

  168. Show the list of your commands typing:

    history

    and re-launch a command using:

    !#

    where # is the command number specifies in the history list.

    I love linux!
    Keep it simple, that’s the trick!!!

  169. Sorry I skipped description for above listed script.This script I wrote for backup of all running non-global zones on Solaris 10.

  171. Why I switched to Linux:
    Mythtv was my first foray into Linux (commercial skipping is FANTASTIC!).
    that branched into OpenSuse since we use SLES at work, and a bit of distro hopping later, I still use OpenSuse.

    I use it now mostly because XP is boring, Vista holds no interest for me (I shouldn’t need to upgrade my machine to run an OS that costs $300+), and Linux is so much fun!

  172. I like Linux because it is free and open source. Other than it is based on Debian which has an excellent package management tool APT.

    My Tip
    1. history -c clears the history of commands.
    2. To run a previous command starting as ssh type !ssh and hit return
    2. Using Thunderbird. If you got a mail containing and image from someone and want to insert that image to your mail that you are composing, do as follows.
    * Open the mail received.
    * Right click on the image and click copy “image location”
    * Go to the composing mail and using menu commands select “Insert->Image”.
    * It will ask for “Image Location”. Paste the location copied.
    * Give some Alternage Text if you want.
    * Press ok.
    Thats it.
    This way you can copy an image from a mail to the compose mail without saving in the local disk.

    Cheers,
    Nilufer

  173. Newbie, google is your best friend. When you’ve asked the correct question the answer WILL be on the web.

  174. Having Xwindows issues? Ctrl-Alt-F2 to a new console. Type “sudo init 3” to change to a text only runlevel, and use nano or vi to edit your xorg.conf file.

  175. 1.How to see bad blocks/sectors in linux partitions
    —————————————

    badblocks -o filename.log /dev/hdax – for IDE disks

    badblocks -o filename.log /dev/sdax – for SCSI disks ( X – 1,2,3..)

  176. If you are using bash shell, below command would be useful for spell mistakes. pls go example below.

    #shopt -s cdspell

    # cd /vr/lok/
    /var/log/
    #[root@ss log]#pwd
    /var/log
    #

  177. Turn of all warning beeps, fast and dirty.
    Instead of editing every configuration file (I know of ~./bashrc, ~./emacs, ~/.inputrc (but its not enough, the bloody sound still apears in some odd circumestances))just add the line
    blacklist pcspkr
    to /etc/modprobe.d/blacklist, voila you will never ever hear that f*cking warning beep again.
    The dirty part about this is that I don’t know if you in some situation really need the pcspkr module, I haven’t found one.

  178. I have switched to linux because, I liked the concept of open source. I wanted to become part of the open source community by making some contributions from my end to the community. I love the concept of help each other by making some contributions.

    Thanks,
    Sathish

  179. Use Ubuntu for your server.
    and you’ll never face MS08-067 Security Problem (netapi32.dll)

    Thanks
    Dody

  180. Hi Vivek,

    I moved to linux because of many reasons,

    1) I can know the indepth working of an OS and interaction with OS applications. I can bring more to Linux that to the so-called user-friendly Windows.
    2) With the openly available source code, I can even make the best coding and required ammaendments to meet my requirements.
    3) Giving something to the world along with the work from the scratch is what I believe and practice most.
    Hurray to the OSS people. Let us strive for a free world. Open up your mind and soul for the sole cause of helping human kind.

  181. Basically Window looks easy but very confusing.
    Linux Looks Complex but doesnt hides how it does the magic. Apart, Linux is very secure and reliable.
    Tips: If you want to know the Make of the Laptop battery you can view this file on RHEL4 Kernel 2.6.
    # cat /proc/acpi/battery/BAT0/info

  182. I don’t know what should I wrote. But I am happy to see a lots response in this topic.

    Therefor here 2 tips for everyone.

    01. undo Firefox closed tab.

    Shift+ctrl+t

    02. How to install firefox
    Download the latest source.
    $ su

    # mv firefox* /usr/local/bin/
    # cd /usr/local/bin/
    # tar -zxvf firefox*

    Log out root with the keys: Ctrl+D
    Type “kmenuedit”/”alacarte” or the “gnome-menu-editor” )

    – Make a new menu entry, call it Firefox and fill in as command: /usr/local/bin/firefox/firefox

    then save

  183. If you use the Terminal a lot (and you should!), you can assign a keyboard shortcut to quickly open a new Terminal window.

    To do this, just head to System > Preferences > Keyboard Shortcuts from the main menu. Now look for “Run a terminal” and click on it, then press the key combination you want to use as a shortcut. I personally use Ctrl+Alt+x.

    Hope you find it useful 🙂

    Regards,
    Yaser

  184. Some tips:
    1- press tab key to auto complete the files & directories full path. It will bring the names of files or directories that start with the pattern you wrote.

    &

    2- press double tab to bring a list of all files & directories that start with the pattern you wrote.

    example:
    if you currently on /usr/bin
    then you issues:

    $ ls -altr pa <--press tab here
    pack pagesize panel-test-applets pargs passwd patch pax
    page pal2rgb pango-querymodules passmgmt paste pathchk
    $ ls -altr pas <--press tab after additional s
    passmgmt passwd paste
    $ ls -altr pass <--press tab after additional s
    passmgmt passwd
    $ ls -altr passwd
    -r-sr-sr-x 1 root sys 27228 Aug 16 2007 passwd

    Example 2:

    $ls -altr wo $ls -altr word-list-compress <-- completed automatically

    Have a nice time scripti[tab] (scripting)

    Amr

  185. Need to back up a PC that won’t boot, but the HDD is still readable (not a hardware error)? Build an .iso CD or usb stick with:

    g4u (“ghost for unix”) which is a boot-floppy/CD that allows one to easily clone PC hard disks by using FTP. Useful for backups and cloning new drives .

    Since dabbling with Linux, starting with RH5 in 1998, I have been digging on these past 2 years with Ubuntu/Debian/Knoppix/DSL distros. I have tried the Ubuntu distro’s for Apple (both Motorola & Intel) and recommend Zimbra as the future of mail server apps (try the open source edition for free!)

    I like Linux because of the flexibility and cooperation of the communities that support it. I tolerate Microsoft because of all of the companies that use it and distribute it with their new hardware. I setup multi-booting because I get to choose what flavor I need, and have started getting deeper into VMWare to test all this cool stuff out there!

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