-------------------------------------------------Noob------------------------------------------------- I. What is Linux? II. Trying it out III. Installing IV. What to do now V. The Console Intro: This tutorial is written with the total Linux n00b in mind. I've seen too many n00bs get totally left in the dark by asking what the best distro is. They seem to only get flooded with too many answers in so short a time. I'm a little bit of a n00b too, so I know how it feels. I will cover a grand total of two basic distros. You may learn to strongly prefer other ones (I do!) but this is just to get you started. I touch on a number of topics that would be impossible to go into in depth in one tutorial, so I encourage you to actively seek out more about the concepts I make reference to. I. What is Linux? Linux is basically an operating system (OS for short). The Windows machine you're (probably) using now uses the Mcft Windows operating system. Ok, so what's so different about Linux? Linux is part of a revolutionary movement called the open-source movement. The history and intricacies of that movement are well beyond the scope of this tutorial, but I'll try and explain it simply. Open source means that the developers release the source code for all their customers to view and alter to fit what they need the software to do, what they want the software to do, and what they feel software should do. Linux is a programmer?s dream come true, it has the best compilers, libraries, and tools in addition to its being open-source. A programmer's only limit then, is his knowledge, skill, time, and resolve. What is a distro? A distro is short for a distribution. It's someone's personal modification or recreation of Linux. What do you mean by distros? I just want Linux! Since Linux is open source, every developer can write his own version. Most of those developers release their modifications, or entire creations as free and open source. A few don't and try to profit from their product, which is a topic of moral debate in the Linux world. The actual Linux is just a kernel that serves as a node of communication between various points of the system (such as the CPU, the mouse, the hard drive etc.). In order to use this kernel, we must find a way to communicate with it. The way we communicate is with a shell. Shells will let us enter commands in ways that make sense to us, and send those commands to the kernel in ways that makes sense to it. The shell most Linux's use it the BASH shell (Bourne Again SHell). The kernel by itself will not do, and just a shell on top of the kernel won?t either for most users; we are then forced to use a distribution. What distro is best? This is not the question you want to ask a large number of people at one time. This is very much like asking what kind of shoe is best, you'll get answers anywhere from running shoes, hiking boots, cleats, to wingtips. You need to be specific about what you plan on using Linux for, what system you want to use it on, and many other things. I will cover two that are quick and easy to get running. They may not be the best, or the quickest, or the easiest, or the most powerful, but this is a guide for getting started, and everyone has to start somewhere. How much does it cost? computer + electricity + internet + CD burner and CDs = Linux I'll let you do your own math. Note however that a few do charge for their distros, but they aren't all that common, and can be worked around. Also, if you lack internet access or a CD burner or CDs or you just want to, you can normally order CDs of the distro for a few dollars apiece. II. Trying it out. Wouldn't it stink if you decide to wipe out your hard drive and install Linux as the sole operating system only to learn that you don't know how to do anything and hate it? Wouldn?t it be better to take a test drive? 95 out of a 100 of you know where I'm heading with this section and can therefore skip it. For those of you who don't know, read on. There are many distros, and most distros try to have something that makes them stand out. Knoppix was the first live-CD distro. Although most of the other main distros have formed their own live-CDs, Knoppix is still the most famous and I will be covering how to acquire it. A live-CD distro is a distribution of Linux in which the entire OS can be run off of the CD-ROM and your RAM. This means that no installation is required and the distro will not touch your hard disk or current OS (unless you tell it to). On bootup, the CD will automatically detect your hardware and launch you into Linux. To get back to Windows, just reboot and take the CD out. Go to the Knoppix website (www.knoppix.com). Look around some to get more of an idea on what Knoppix is. When you're ready, click Download. You'll be presented with a large amount of mirrors, some of which have ftp and some of which have http also. note: the speed of the mirrors vary greatly, and you may want to change mirrors should your download be significantly slow. Choose a mirror. Read the agreement and choose accept. You'll probably want to download the newest version and in your native language (I'll assume English in this tutorial). So choose the newest file ending in -EN.iso note: you might want to also verify the md5 checksums after the download, if you don't understand this, don't worry too much. You just might have to download it again should the file get corrupted (you'll have to anyway with the md5). Also, a lot of times a burn can be botched for who-knows what reason. If the disk doesn?t work at all, try a reburn. Once the .iso file is done downloading, fire up your favorite CD-burning software. Find the option to burn a CD image (for Nero, this is under copy and backup) and burn it to a disk. Make sure you don't just copy the .iso, you have to burn the image, which will unpack all the files onto the CD. Once the disk is done, put it in the CD-ROM drive and reboot the computer. While your computer is booting, enter CMOS (how to get to CMOS varies for each computer, some get to it by F1 or F2 or F3, etc.) Go to the bootup configuration and place CD-ROM above hard disk. Save changes and exit. Now, Knoppix will automatically start. You will be presented with a boot prompt. Here you can input specific boot parameters (called cheatcodes), or just wait and let it boot up using the default. note: Sometimes USB keyboards do not work until the OS has somewhat booted up. Once you?re actually in Knoppix, your USB keyboard should work, but you may not be able to use cheatcodes. If you need to, attach a PS/2 keyboard temporarily. Also, if a particular aspect of hardware detection does not work, look for a cheatcode to disable it. Cheatcodes can be found on the Knoppix website in text format (or in HTML at www.knoppix.net/docs/index.php/CheatCodes). Upon entering the KDE desktop environment, spend some time exploring around. Surf the web, get on IM, play some games, explore the filesystem, and whatever else seems interesting. When your done, open up the console (also called terminal, xterm, konsole, or even shell) and get ready for the real Linux. See section V for what to do from here. note: to function as root (or the superuser) type su. It's not entirely necessary that you are a console wizard at this point (although you will need to be sooner or later), but a little messing around wont hurt. Just as there are many Linux distros, so there are also many types of Knoppix. I won?t go into using any of them, but they should all be somewhat similar. Some of them include: Gnoppix, Knoppix STD, Morphix, and PHLAK. Other distros also have live-CDs. III. Installing I will guide you through the installation of Fedora Core 2. The reason I chose Fedora is because it contains the Anaconda installer, which is a very easy installer. Download the discs from here: http://download.fedora.redhat.com/pub/fedo...ore/2/i386/iso/ If the link doesn?t work, then go to www.redhat.com and navigate your way to downloading Fedora (odds are your architecture is i386). You will want to download the FC2-i386-disc1.iso and burn it using the method for Knoppix. Do the same for all the discs. Note: do NOT download the FC2-i386-SRPMS-disc1.iso files. Now, once you?re ready, insert disc 1 into the drive and reboot. The installer should come up automatically (if not, then see the Knoppix section on CMOS). Note: installer may vary depending on version. Follow directions best you can using your best judgement. 1. Language: choose English and hit enter 2. Keyboard: choose us (probably) and hit enter 3. Installation media: choose local CDROM (probably) and hit enter 4. CD test: you can choose to test or skip 5. Intro: click next 6. Monitor: choose your monitor to the best of your ability, if you?re unsure, choose on of the generic ones 7. Installation type: choose which ever you want (default should be fine) 8. Partition: choose to automatically partition (unless you know what you?re doing) 9. Partition: the default partitions should suffice 10. Boot loader: choose your boot loader (grub for default) 11. Network settings: choose the correct settings for your network (generally, don?t mess with anything unless you know what you?re doing) 12. Firewall: you can choose a firewall if you want to 13. Language support: choose any additional language support you want 14. Time zone: pick your time zone 15. Root password: set your root password (root is the admin, or superuser; you want it to be very secure) 16. Packages: choose which packages you want to install. For hard drives over 10 gigs, you can go ahead and choose all packages (depending on how much disk space you plan on taking up later, note that most everything you?ll need is a package: the exception being large media files). You will generally want to install all the packages you think you?ll ever need. Two desktop environments aren?t necessary. Make sure you have at least one and the X window system! (if you want a GUI that is). I suggest you get all the servers too. Note: Knoppix uses the KDE Desktop environment 17. Make sure everything is all right, and install 18. You can create a boot disk if you want Note: Desktop environments might have a set-up once you enter them IV What to do now Now that you have a Linux set-up and running, there are many paths you can head down. First, you should explore your GUI and menus. Browse the web with Mozilla, get on IM with GAIM, play games, add/delete users, check out OpenOffice, and anything else that might be part of your daily use. Also, set up a few servers on your computer to play around with, specifically SMTP (*wink*wink*), FTP (vsftp is a good one), and either telnet or SSH (OpenSSH is a good one). The setup and use of these are beyond the scope of this tutorial, but researching them could prove to be very educational. The filesystem The Linux (and Unix) filesystem is different from the normal Windows that you?re used to. In Windows, your hard drive is denoted ?C:\? (or whatever). In Linux, it is called the root directory and is denoted ?/?. In the / directory, there are several default folders, including dev (device drivers) mnt (mount) bin (binaries) usr (Unix System Resources) home, etc, and others. I encourage you to explore around the whole file system (see section V) and research more. Once you are well situated, it?s time to get into the heart and power of Linux: the console. The next session will guide you through it and set you on the path to finding out how to do stuff for yourself. You will (probably) want to start learning to rely less and less on the GUI and figure out how to do everything through the console (try launching all your programs from the console, for example). V. The Console The Console might look familiar to DOS if you?ve ever used it. The prompt should look something like the following: AvatharTri@localhost avathartri$ With the blinking _ following it. This can vary greatly as it is fully customizable. Let?s get started with the commands. First, let?s explore the file system. The command ls will "list" the files in the current directory. Here?s an example: AvatharTri@localhost avathartri$ ls It should then display the contents of the current directory if there are any. Almost all commands have options attached to them. For example, using the -l option, which is short for "long" will display more information about the files listed. AvatharTri@localhost avathartri$ ls -l We will get into how to find out the options for commands and what they do later. The second command to learn will be the cd command, or "change directory". To use it, you type cd followed by a space and the directory name you wish to go into. In Linux, the top directory is / (as opposed to C:\ in Windows). Let?s get there by using this command: AvatharTri@localhost avathartri$ cd / AvatharTri@localhost /$ Now, we are in the top directory. Use the ls command you learned earlier to see everything that?s here. You should see several items, which are directories. Now, let?s go into the home directory: AvatharTri@localhost /$ cd home AvatharTri@localhost home$ And you can now ls and see what?s around. In Linux there are some special symbol shortcuts for specific folders. You can use these symbols with cd, ls, or several other commands. The symbol ~ stands for your home folder. One period . represents the directory your currently in. Two periods .. represent the directory immediately above your own. Here?s an example of the commands: AvatharTri@localhost home$ cd ~ AvatharTri@localhost avathartri$ This moved us to our user?s personal directory. AvatharTri@localhost avathartri$ cd . AvatharTri@localhost avathartri$ cd .. AvatharTri@localhost home$ The cd .. moved us up to the home directory. As you?ve probably noticed by now, the section behind the prompt changes as you change folders, although it might not always be the case as it?s up to the personal configuration. You can use these symbols with the ls command also to view what is in different folders: AvatharTri@localhost home$ ls ~ AvatharTri@localhost home$ ls .. And you can view what is in a folder by specifying its path: AvatharTri@localhost home$ ls / AvatharTri@localhost home$ ls /home The last command we will cover as far as finding your way around the filesystem is the cat command. The cat command will show the contents of a file. Find a file by using the cd and ls commands and then view its contents with the cat command. AvatharTri@localhost home$ cd [directory] AvatharTri@localhost [directory]$ ls AvatharTri@localhost [directory]$ cat [filename] Where [directory] is the directory you want to view and [filename] is the name of the file you want to view. Omit the brackets. Now, if the file you viewed was a text file, you should see text, but if it wasn?t, you might just see jumbled garbage, but this is ok. If the file goes by too fast and goes off the screen, don?t worry, we will get to how to scroll through it later. One of the most useful commands is the man command, which displays the "manual" for the command you want to know more about. To learn more about the ls command: AvatharTri@localhost home$ man ls And you will see the manual page for ls. It displays the syntax, a description, options, and other useful tidbits of information. Use the up and down arrows to scroll and press q to exit. You can view the manual pages for any command that has one (most commands do). Try this out with all the commands that you know so far: AvatharTri@localhost home$ man cd AvatharTri@localhost home$ man cat AvatharTri@localhost home$ man man One very crucial option to the man command is the -k option. This will search the descriptions of manual pages for the word you specify. You can use this to find out what command to do what you need to do. For example, let?s say we want to use a text editor: AvatharTri@localhost home$ man -k editor And you should see a list of apps with a short description and the word "editor" in the description. With a blank prompt, you can hit tab twice for Linux to display all the possible commands. For Linux to display all the commands beginning with a certain letter or series of letters, type those letters and hit tab twice. Note: This is actually a function of BASH and not Linux, but BASH is the default Linux shell. Now that you know a little about moving around the filesystem and viewing manual pages, there is one more trick that we will cover to help you out. Remember how the man pages were scrollable as in you could use the arrow keys to scroll up and down? That is because the man pages use something called the less pager. We?re not going to go into what this does exactly and how it works, but that?s definitely something that you will want to look up. Here?s how to use the less pager with a file: AvatharTri@localhost home$ cat [filename] | less That uses something called a pipe. The line is the vertical line above enter on your keyboard. Briefly, what this does is take the output from the cat command, and stick it in the less pager. By doing this, you can view files that would normally run off the screen and scroll up and down. Some final commands to check out: mkdir - make directories cp - copy file mv - move file rm - remove file rmdir - remove directory grep - search a file for a keyword pwd - display current working directory top - display system resources usage (kill the program with control + c) -------------------------------------------------Advance------------------------------------------------- Tips Speeding up your hard drive (#1) Get faster file transfer by using 32-bit transfers on your hard drive Just add the line: hdparm -c3 /dev/hdX to a bootup script. If you use SuSE or other distros based on SYS V, /sbin/init.d/boot.local should work for you. This enables 32-bit transfer on your hard drive. On some systems it can improve transfer performance by 75%. To test your performance gain, type: hdparm -t -T /dev/hdX Protecting yourself from being a spam base(#2) Sendmail allows for someone to telnet to port 25 and do an expn (expand) to see what users and aliases are on your machine. Also, vrfy (verify) means someone can get legal e-mail addresses from your box and send spam through your machine. Don't want that, so look in your /etc/sendmail.cf file for a line that looks like this: ############### # Options # ############### Now cut and paste these next few lines below that: # turning off the expand option and requiring a helo from # a remote computer Opnoexpn,novrfy,needmailhelo Now there is no expansion, no verify, and sendmail requires a helo with a legitimate DNS in order to use the mailer. Then look in your /etc/mail/aliases file and ensure you have only your own boxen and/or subnet in there as OK or RELAY. That will help cut down on spammers' ability to find relay machines to do their dirty work for them. Cleaning up Netscape crashes(#3) You have a tip about Netscape leaving copies of itself running below, but you can make a general shell script to clean up a Netscape crash like this: #!/bin/sh #kill.netscape killall -9 netscape rm ~/.netscape/lock Then all your users can use it and clean up the dreaded hundred instances of Netscape running when it crashed. Change netscape to netscape-communicator or netscape-navigator as appropriate More DOS-like commands(#4) Many people are moving to Linux because they miss the stability of good old DOS. In that light, many users are typing DOS commands (which originated from UNIX in the first place) that look fine but cause errors. The command "cd.." in DOS is perfectly valid, but Linux balks. This is because "cd" is a command, and any parameter for that command must be separated from the command by a space. The same goes for "cd/" and "cd~". A quick fix is here. Use your favorite text editor in your home directory to edit the file ".bashrc". The period is there on purpose, this hides the file from normal ls display. Add the lines: alias cd/="cd /" alias cd~="cd ~" alias cd..="cd .." And I usually add these... alias md="mkdir" alias rd="rmdir -i" alias rm="rm -i" and my first and still favorite alias... alias ls="ls --color" alias is a powerful tool, and can be used in the .bashrc script as well as from the command line. You can, if you want to spend the time, create your own group of shell commands to suit how you work. As long as you put them in your .bashrc file, they'll be there everytime you log in. Note that if you frequently log in as root, you might want to copy /home/username/.bashrc to /root/.bashrc to keep yourself sane. Resurrecting corrupted floppies(#5) Here's how to make a floppy disk with "track-0 bad" reusable again: If the track zero of a floppy disk is found to be bad, no DOS or Windows utility is going to do anything about it--you just have to throw it in your unrecycle bin. This tip cannot recover the data, but can make the disk carry things again, at least for the time being (moments of desperation). How to: (A) Format the disk with Linux. Build a Linux file system (don't use mformat). I did this some time before by invoking the makebootdisk command (in Slakware) and stopped after the formatting was over. There should be better ways to do it in RedHat 5.2 or other recent versions. ( Reformat the disk with Windows. Use the DOS window and the /u option while formatting. Using DOS-like commands(#6) There's a package called mtools which is included with most of the distributions out there. There are several commands for basic DOS stuff. For example, to directory the floppy drive, type mdir a:. This is rather handy--you don't need to mount the floppy drive to use it. Other commands are: mattrib , mcd, mcopy, mdel, mformat, mlabel, mren (rename), mmd, mrd, and mtype. This doesn't work for reading from hard disks. In that case, you would add entries to /etc/fstab, drive type msdos for fat16 partitions, and vfat for fat32. Copying files from Linux to Windows 98 or 95B (FAT32)(#7) It's as easy as installing the program explore2fs. It uses a Windows Explorer interface and supports drag-and-drop. I have found it reliable and useful for migrating files from my RedHat 6.1 partition to my Win95B partition quickly and with a minimum of fuss. It's available free--as all software should be--from this URL: CODE http://uranus.it.swin.edu.au/~jn/linux/explore2fs.htm Installing in partitions(#8) I am using SuSE Linux, which has some interesting options (I don't know if RedHat or other distributions offer you this, too). 1. You can install Linux on a single file in your Windows Partition. Nice to try it out, but I guess it is not that fast then. You can load it then with a DOS program, loadlin. 2. Use Fips or Partition Magic. Defragment your hard drive (you should do this for Point 1, too) and split it up. I guess most users just have one partition, which you should split up into at least three: one for the Linux files, and a smaller swap partition (take about 32 to 64 MB, depending on your RAM--less RAM needs bigger swap partitions). If you decide later to deinstall Linux you can always delete both partitions and create one big one for Windows again. Fips is a stupid command line program, but if you're too lazy to read at least a little bit, then you should stop thinking about Linux anyway... Command Pipelines(#9) Pipes are easy. The Unix shells provide mechanisms which you can use them to allow you to generate remarkably sophisticated `programs' out of simple components. We call that a pipeline. A pipeline is composed of a data generator, a series of filters, and a data consumer. Often that final stage is as simple as displaying the final output on stdout, and sometimes the first stage is as simple as reading from stdin. I think all shells use the "|" character to separate each stage of a pipeline. So: data-generator | filter | ... | filter | data-consumer Each stage of the pipeline runs in parallel, within the limits which the system permits. Hey, look closely, because that last phrase is important. Are you on a uni-processor system because if you are, then obviously only one process runs at a time, although that point is simply nitpicking. But pipes are buffers capable of holding only finite data. A process can write into a pipe until that pipe is full. When the pipe is full the process writing into it blocks until some of the data already in the pipe has been read. Similarly, a process can read from a pipe until that pipe is empty. When it's empty the reading process is blocked until some more data has been written into the pipe. What is IP masquerading and when is it of use?(#10) IP masquerading is a process where one computer acts as an IP gateway for a network. All computers on the network send their IP packets through the gateway, which replaces the source IP address with its own address and then forwards it to the internet. Perhaps the source IP port number is also replaced with another port number, although that is less interesting. All hosts on the internet see the packet as originating from the gateway. Any host on the Internet which wishes to send a packet back, ie in reply, must necessarily address that packet to the gateway. Remember that the gateway is the only host seen on the internet. The gateway rewrites the destination address, replacing its own address with the IP address of the machine which is being masqueraded, and forwards that packet on to the local network for delivery. This procedure sounds simple, and it is. It provides an effective means by which you can provide second class internet connections for a complete LAN using only one (internet) IP address. Setting UTC or local time(#11) When Linux boots, one of the initialisation scripts will run the /sbin/hwclock program to copy the current hardware clock time to the system clock. hwclock will assume the hardware clock is set to local time unless it is run with the --utc switch. Rather than editing the startup script, under Red Hat Linux you should edit the /etc/sysconfig/clock file and change the ``UTC'' line to either ``UTC=true'' or ``UTC=false'' as appropriate. Setting the system clock(#12) To set the system clock under Linux, use the date command. As an example, to set the current time and date to July 31, 11:16pm, type ``date 07312316'' (note that the time is given in 24 hour notation). If you wanted to change the year as well, you could type ``date 073123161998''. To set the seconds as well, type ``date 07312316.30'' or ``date 073123161998.30''. To see what Linux thinks the current local time is, run date with no arguments. Setting the hardware clock(#13) To set the hardware clock, my favourite way is to set the system clock first, and then set the hardware clock to the current system clock by typing ``/sbin/hwclock --systohc'' (or ``/sbin/hwclock --systohc --utc'' if you are keeping the hardware clock in UTC). To see what the hardware clock is currently set to, run hwclock with no arguments. If the hardware clock is in UTC and you want to see the local equivalent, type ``/sbin/hwclock --utc'' Setting your timezone(#14) The timezone under Linux is set by a symbolic link from /etc/localtime[1] to a file in the /usr/share/zoneinfo[2] directory that corresponds with what timezone you are in. For example, since I'm in South Australia, /etc/localtime is a symlink to /usr/share/zoneinfo/Australia/South. To set this link, type: ln -sf ../usr/share/zoneinfo/your/zone /etc/localtime Replace your/zone with something like Australia/NSW or Australia/Perth. Have a look in the directories under /usr/share/zoneinfo to see what timezones are available. [1] This assumes that /usr/share/zoneinfo is linked to /etc/localtime as it is under Red Hat Linux. [2] On older systems, you'll find that /usr/lib/zoneinfo is used instead of /usr/share/zoneinfo. See also the later section ``The time in some applications is wrong''. Zombies(#15) What are these zombie processes that show up in ps? I kill them but they don't go away! Zombies are dead processes. You cannot kill the dead. All processes eventually die, and when they do they become zombies. They consume almost no resources, which is to be expected because they are dead! The reason for zombies is so the zombie's parent (process) can retrieve the zombie's exit status and resource usage statistics. The parent signals the operating system that it no longer needs the zombie by using one of the wait() system calls. When a process dies, its child processes all become children of process number 1, which is the init process. Init is ``always'' waiting for children to die, so that they don't remain as zombies. If you have zombie processes it means those zombies have not been waited for by their parent (look at PPID displayed by ps -l). You have three choices: Fix the parent process (make it wait); kill the parent; or live with it. Remember that living with it is not so hard because zombies take up little more than one extra line in the output of ps. How do i give users an ftp only account (no telnet, etc).(#16) give them shell which doesn't work, but is listed in /etc/shells for example /bin/false... How to do backup with tar?(#17) You can mantain a list of files that you with to backup into a file and tar it when you wish. tar czvf tarfile.tar.gz -T list_file where list_file is a simple list of what you want to include into the tar i.e: /etc/smb.conf /root/myfile /etc/ppp (all files into the /etc/ppp directory) /opt/gnome/html/gnome-dev-info.html How to keep a computer from answering to ping?(#18) a simple "echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all" will do the trick... to turn it back on, simply "echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all" Customizing your directory colors.(#19) I know a lot of you know the command ls --color. Which displays your directory with colors. But, a lot of people may not know that those colors are customizable. All you need to do is add the following line to your /etc/bashrc file. eval `dircolors /etc/DIR_COLORS` And then all of the color configuration can be found in the file /etc/DIR_COLORS Frozen Xwindow(#20) If your Xwindow freezes sometimes, here are two ways that you may try to kill your server. The first is the simple simple way of killing your X server the key combination: Ctrl+Alt+Backspace The second way is a little more complicated, but it works most of the time. Hit Ctrl+Alt+F2 to startup a virtual console, then log in with your user name and password and run: # ps -ax | grep startx This will give you the PID of your Xserver. Then just kill it with: # kill -9 PID_Number To go back to your first console, just hit Alt-F1 Converting all files in a directory to lowercase.(#21) #!/bin/sh # lowerit # convert all file names in the current directory to lower case # only operates on plain files--does not change the name of directories # will ask for verification before overwriting an existing file for x in `ls` do if [ ! -f $x ]; then continue fi lc=`echo $x | tr '[A-Z]' '[a-z]'` if [ $lc != $x ]; then mv -i $x $lc fi done Wow. That's a long script. I wouldn't write a script to do that; instead, I would use this command: for i in * ; do [ -f $i ] && mv -i $i `echo $i | tr '[A-Z]' '[a-z]'`; done; on the command line. Script to view those compressed HOWTOs.(#22) From a newbie to another, here is a short script that eases looking for and viewing howto documents. My howto's are in /usr/doc/faq/howto/ and are gzipped. The file names are XXX-HOWTO.gz, XXX being the subject. I created the following script called "howto" in the /usr/local/sbin directory: #!/bin/sh if [ "$1" = "" ]; then ls /usr/doc/faq/howto | less else gunzip -c /usr/doc/faq/howto/$1-HOWTO.gz | less fi When called without argument, it displays a directory of the available howto's. Then when entered with the first part of the file name (before the hyphen) as an argument, it unzips (keeping the original intact) then displays the document. For instance, to view the Serial-HOWTO.gz document, enter: $ howto Serial Util to clean up your logfiles.(#23) If you're like me, you have a list with 430 subscribers, plus 100+ messages per day coming in over UUCP. Well, what's a hacker to do with these huge logs? Install chklogs, that's what. Chklogs is written by Emilio Grimaldo, grimaldo@panama.iaehv.nl, and the current version 1.8 available from ftp.iaehv.nl:/pub/users/grimaldo/chklogs-1.8.tar.gz. It's pretty self explanatory to install(you will, of course, check out the info in the doc subdirectory). Once you've got it installed, add a crontab entry like this: # Run chklogs at 9:00PM daily. 00 21 * * * /usr/local/sbin/chklogs -m Handy Script to Clean Up Corefiles.(#24) Create a file called rmcores(the author calls it handle-cores) with the following in it: #!/bin/sh USAGE="$0 " if [ $# != 2 ] ; then echo $USAGE exit fi echo Deleting... find $1 -name core -atime 7 -print -type f -exec rm {} \; echo e-mailing for name in `find $1 -name core -exec ls -l {} \; | cut -c16-24` do echo $name cat $2 | mail $name done And have a cron job run it every so often. Moving directories between filesystems.Quick way to move an entire tree of files from one disk to another (#25) (cd /source/directory && tar cf - . ) | (cd /dest/directory && tar xvfp -) [ Change from cd /source/directory; tar....etc. to prevent possibility of trashing directory in case of disaster.] Finding out which directories are the largest.Ever wondered which directories are the biggest on your computer? Here's how to find out.(#26) du -S | sort -n How do I stop my system from fscking on each reboot?(#27) When you rebuild the kernel, the filesystem is marked as 'dirty' and so your disk will be checked with each boot. The fix is to run: rdev -R /zImage 1 This fixes the kernel so that it is no longer convinced that the filesystem is dirty. Note: If using lilo, then add read-only to your linux setup in your lilo config file (Usually /etc/lilo.conf) How to avoid fscks caused by "device busy" at reboot time.(#28) If you often get device busy errors on shutdown that leave the filesystem in need of an fsck upon reboot, here is a simple fix: To /etc/rc.d/init.d/halt or /etc/rc.d/rc.0, add the line mount -o remount,ro /mount.dir for all your mounted filesystems except /, before the call to umount -a. This means if, for some reason, shutdown fails to kill all processes and umount the disks they will still be clean on reboot. Saves a lot of time at reboot for me. How to find the biggest files on your hard-drive.(#29) ls -l | sort +4n Or, for those of you really scrunched for space this takes awhile but works great: cd / ls -lR | sort +4n A script for cleaning up after programs that create autosave and backup files.(#30) Here is a simple two-liner which recursively descends a directory hierarchy removing emacs auto-save (#) and backup (~) files, .o files, and TeX .log files. It also compresses .tex files and README files. I call it 'squeeze' on my system. #!/bin/sh #SQUEEZE removes unnecessary files and compresses .tex and README files #By Barry tolnas, tolnas@sun1.engr.utk.edu # echo squeezing $PWD find $PWD \( -name \*~ -or -name \*.o -or -name \*.log -or -name \*\#\) -exec rm -f {} \; find $PWD \( -name \*.tex -or -name \*README\* -or -name \*readme\* \) -exec gzip -9 {} \; How to find out what process is eating the most memory.(#31) ps -aux | sort +4n -OR- ps -aux | sort +5n How do I find which library in /usr/lib holds a certain function?(#32) What if you're compiling and you've missed a library that needed linking in? All gcc reports are function names... Here's a simple command that'll find what you're looking for: for i in *; do echo $i:;nm $i|grep tgetnum 2>/dev/null;done Where tgetnum is the name of the function you're looking for. I compiled a small test program in C, but when I run it, I get no output!(#32) You probably compiled the program into a binary named test, didn't you? Linux has a program called test, which tests if a certain condition is true, it never produces any output on the screen. Instead of just typing test, try: ./test

Last edited by MargZ (2008-05-19 01:56:59)