Administration Tutors:

Tutor_01: Recovering Lost Data

If you delect an important directory, perhaps files you need, or even a partition, don't cry yet, you can recover almost all lost files.

The Mini Tutor lets you know how-to recover lost files and directories into a reiserfs partition, but you can also recover files from ext2 and ext3. If you have a livecd or another distro installed, you can recover almost all files without problems.

You are going to use reiserfsck command, a great tool for check and correct partitions. First you have to boot using the livecd or your second installed system. After finished the boot, umount your partition where lost files were included, for example, /dev/hda5, umount /dev/hda5.

After umount your partition, type: reiserfsck --rebuild-tree -S -l /root/recover..log /dev/hda5 The above command is going to rebuild your partition tree and remove your lost data to lost+found directory, also is going to correct the partition. The command send log messages to /root/recover.log using -l option, and is going to scan whole partitions, -S option, instead of only used space.

You have to wait a while for the command, but after it finishes, you probably have almost all your files saved into /lost+found directory. Mount again your partition, mount /dev/hda5, and go to lost+found directory, all directories don't have anymore their name and they are identified by a number, but inside all your files remain using original names, you have to look inside to find files you want to recover.

Tutor_02: Find The Package That Contains a File

This Mini Tutor is based on an interesting tip from Dicas-L, a brazilian webpage dedicated to Linux tips, and it is about find which package contains a file.

If you have a .rpm package you can find by typing: rpm -qf filename If you have a .deb package you can find by typing: dpkg -S

But Slackware and GoblinX use Slackware package (.tgz) and packages included are listed in /var/log/packages.

You can find which package contains a file by using following method: Open a console and go to /var/log/packages: cd /var/log/packages. Type: grep -lir 'filename' *

The grep command uses a "-l" option to list names of  files containing filename, and "-i" to ignore case distinctions and "-r" to do a recursively search.

The command lists files names which is equal to package name.
For example: grep -lir 'libdb' *
Result HERE: aaa_elflibs-10.1.0-i486-1 xfce-4.2.2-i486-1

Tutor_03: Clean Your Installed System

You must from time to time clean your system and remove not used traces left, like files and occulted folders. There are a lot of abandoned traces in your installed system and you don't know.

First of all you have to control and clean all logs files. Logs files use to be saved at /var/log folder and as it one receives some messages while you are using the system, they are increasing their sizes while you are reading this mini tutor. You can use logrotate to rotate those logs - we are going to talk about it later - or remove and recreate mannually.

Another files you have to remove are removed packages description, every packages has a description file inside /var/log/packages and some a script inside /var/log/scripts, when you remove a package these files are not removed only moved to /var/log/removed_packages and removed_scripts, and you can remove those files.

About packages, they have a list of contents, so if you add some files after install a package, these files are not removed when you remove the package, like for example, you installed Mplayer and after the instalation you save a new skin inside Mplayer folder, when you remove Mplayer package the folder is going to not be removed because of the skin included after, you have to remove mannually or list all files added into /var/log/mplayer package description.  If you want to have more control, try rebuild the package and include the skin before install it.

Inside your home folder there are some occulted directories (.) like .config, .kde, every apllication when used for the first time will add a folder like that, those folders are used to restore some settings and information about the user and the applications itself, but when you remove the application, the occulted folder remains, you have to remove those folders mannually from time to time. In some case it's better don't remove the occulted folder, it's the case if you plain to use again the application in the future. One occulted folder which increases size very fast it's .thumbnails, that folder contains thumbnails images used by you and after a few week it can be more than 1MB. Another occulted folder you have to look is .mozilla, used by Mozilla, Firefox... You have to clean caches, cookies and pages, and also you have to mannualy remove your email folders because even when you delete an email inside the trash it still have some traces left. If you are using Mozilla, open a xterm and type 'du .mozilla', to see the size, I just did it and I got 179MB of size.

If you are not going to use languages you can remove locale files and other files and don't forget also to clean /tmp from time to time. If you have a Nvidia card and you install a new driver version, you can remove Nvidia files inside /var/lib/nvidia, like 101, 102, 103. Sometimes when you upgrade a package, doc folder from old one are not removed, you have to control all doc folders.

Another common extensions is: (.~). The extension is used for backup of changed files, when you edit a file and save again, a .~ is created and you can remove it. There are some applications to help you to keep clean the system, but you have to do it by yourself sometimes.

Tutor_04: The Fstab

The Fstab is a configuration file (text) which contains information of all the partitions and storage devices in your computer, and also information about proc, devpts and more.

From Fstab Man Page: "The  file fstab contains descriptive information about the various file systems.  Fstab is only read by programs, and not written;  it  is  the duty  of  the system administrator to properly create and maintain this file.  Each filesystem is described on a separate line; fields on  each line are separated by tabs or spaces.  Lines starting with '#' are comments.  The order of records in fstab  is  important  because  fsck, mount,  and umount sequentially iterate through fstab doing their thing."

It's essential understand the fstab and know how to edit it to fit your needs. It contains information of where your partitions and storage devices should be mounted and how, and as it is just a plain text file, you can open and edit it with any text editor you are familiar with. However, note that you must have the root privileges before editing fstab. So, in order to edit the file, you must either log in as root or use the su command to become root. The fstab it's inside /etc folder.

An Fstab example:

/dev/hda7     /                            auto          defaults                            1  1
/dev/hda1     /mnt/hda1             auto         defaults                             0  0
/dev/hda5     /mnt/hda5             ext3         defaults                             0  0
/dev/hdc       /mnt/cdrom[hdc]   iso9660    noauto,owner,ro                 0  0
/dev/sdb1     /mnt/sdb                vfat          auto,users,suid,dev,exec    0  0
/dev/fd0        /mnt/floppy           auto         noauto,user                        0  0
devpts          /dev/pts                 devpts      gid=5,mode=620               0  0
proc              /proc                     proc         defaults                              0  0

As you can see at above example, the first field indicates the block special device or remote filesystem to be mounted, the second field describes the mount point of the device, the third field indicates the type of the filesystem, the fourth field  describes mount options, and the fifth field is used by dump and the sixty field is used by fsck.

The first field describes the device as created by other scripts or by yourself, also by mknod, those devices are in the case of GoblinX, configured at boot, because as a livecd, GoblinX needs to rebuild your fstab each boot to be able to boot from differents machines. Those devices describes your hardware, your harddisk, cdroms, floppies, and more. The first line of the above example tells we have a partition called hda7, it means that 7 is the numeric number of a partition inside our harddisk, and this harddisk are connected to first IDE master (hda). You can notice one cdrom connected to second IDE master (hdc), also an USB device found as sdb1, and a floppy found as fd0.

The second field describes where the devices is going to be mounted. Linux systems mount your partition and devices, it means to access your harddisk, for example, you must mont it first, and the job of mounting is commanded by fstab. The above example indicates all mount points, for example, you partition hda1 are mounted in /mnt/hda7, if you wish to access any files inside that partition, you can find it inside /mnt/hda7. It not for default works like C:, D:, E:, but you can use those letters to define your mount points, too.

The third field is very important because defines the type of the filesystem. Cdroms are defined as iso9660, for example, floppies and harddisk partition can be defined by using their filesystem, like /dev/sdb1 as vfat, or just as auto, auto option is going to try find your filetype for you.

The forth field includes options to be used by mount command. There are several options you can use, some are described above on the example, like defaults, auto (mount automatically), users(allows any user to mount), and more. You must study those options to better useyour fstab.

The fifth field is the dump option. Dump checks it and uses the number to decide if a filesystem should be backed up. If it's zero, dump will ignore that filesystem. If you take a look at the example, you'll notice that zero is most commom option.

The sixty field is used by fsck option. Fsck looks at that number to determine in which order the filesystems should be checked. If it's zero, fsck won't check the filesystem.

The FSTAB is necessary for all linux systems and must contain your devices in order to let you use important devices like harddisk, cdroms and floppy disc. While using the GoblinX as livecd, you do not need to worry about fstab because the livecd is going to find your devices and create a correct fstab, but if you have an installed distro, you have to pay attention to your fstab or it cannot work well.

If you cannot access your cdrom, or a partition, probably is some mistake on fstab file.

Tutor_05: Console [Terminal] & Errors

Everyone is going someday to use a console on Linux, and for some novice users the need to use a console brings fear, but a console is one of most important instrument on Linux, not only to run bash and scripts, but also to let you know more about your system, applications and errors.

Probably the main place to find and know about errors are log files, but you can know about errors while using a console.

Open a console and type 'gimp' to start the gimp, the results could be lines like following ones:

bash-3.00$ gimp
/usr/lib/gimp/2.0/plug-ins/helpbrowser: error while loading shared libraries: libgtkhtml-2.so.0: cannot open shared object file: No such file or directory

(gimp:7749): LibGimpBase-WARNING **: gimp: wire_read(): error
/usr/lib/gimp/2.0/plug-ins/print: error while loading shared libraries: libgimpprint.so.1: cannot open shared object file: No such file or directory

Those lines indicate some missing libraries, Gimp is going to work without those libraries, but you can correct the problem. The helpbrowser plugin uses a libgtkhtml, so to run the plugin you need to install the library.

It's a very commom problem the missing libraries. If you cannot run a program, probably you are missing some libraries, so if you click on an icon and the program do not start, open a console and type its command to see if you get any error.

Another important example of errors and console is used to compile applications. You need a console to compile an application, or the kernel, and as you are using a console you can see the output of all commands. An example result of ./configure command:

checking for C compiler default output file name... configure: error: C compiler cannot create executables

It's easy to identify the problem above because there is no C compiler to compile a program, but the configure command is going to look for all dependencies for you, you just need to check the log file. It's also very usefull pay attention to make command and its errors, sometimes you are going to see an Error:1 stopping the compilation because an include file are missing. Includes files are not be part of a program, but you need them to compile the program.

Sometimes the command used for you only gives a warning message, for example:

bash-3.00$ pyslsk
You do not have Python Vorbis bindings installed. Get them
from http://www.vorbis.com/download_unix_1.0.1.psp or others
will not be able to see the lengths and the bitrates of Ogg
Vorbis files that you share. If you're using Debian, install
the python-pyvorbis package.

In the above example, the Pyslsk program tells me that I need Python Vorbis to share bitrates of Ogg Vorbis files, it's only a warning message, but relevant.

Another good example are about crashes. During this week a friend got an error while using Open Office, the SWriter crashes after a few minutes, after open a console and start Open Office using it, we got this message:

terminate called after throwing an instance of 'com::sun::star::configuration::backend
::InsufficientAccessRightsException'
terminate called recursively
KCrash: Application 'soffice.bin' crashing...
soffice.bin: Fatal IO error: client killed

As you can see, you probably use the console to compile applications and drivers, to run shell scripts or bash commands, but you can also use it to identify errors, crashes problems, missing libraries, missing includes and several problems in your system.

Use the console every time you got an error.

Tutor_06: Proc Folder & Processes

The "The Proc Folder and Processes" minitutor speaks about only processes information stored at /proc folder.

The proc folder is like a filesystem inside the filesystem, used to restore and show data kernel, it means, inside /proc
folder you have a lot of information about processes, hardware, drivers and more.

From Proc Man Pages
"/proc is a pseudo-filesystem which is used as an interface to kernel data structures rather than reading and
interpreting /dev/kmem. Most of it is read-only, but some files  allow kernel variables to be changed."

The /proc folder contains all runnings process information, showed by their ID.
For example: You are running gpm to control your mouse, and by using the command 'ps aux | grep gpm' you find that gpm has a process ID 2246, so if you type 'ls /proc/2246', you are going to get:

bash-3.00# ls /proc/2246
auxv     cwd      exe  ipaddr  mem     oom_adj    root     smaps  statm   task
cmdline  environ  fd   maps    mounts  oom_score  seccomp  stat   status

As you can see there are several pseudo-files and directories containing source of information about the gpm process.

The 'cmdline' indicates exactly the command running, in the example, when you use 'cat /proc/2246/cmdline',
you get '/usr/sbin/gpm-m/dev/mouse-tps2'.

The 'stat' is the one used by ps command to display information about the process. The ps command used
above also let you know about your running process. The info get in the stat is prepared to ps command,
like following example.

bash-3.00# cat /proc/25998/stat
25998 (xinit) S 5754 5754 23844 1025 5754 8388864 584 0 4 0 0 0 0 0 16 0 1 0 43669 2347008
156 4294967295 134512640 134521372 3215734896 0 0 0 0 0 12807 0 0 0 17 0 0 0

The 'status' is like 'stat' but provides much of the information in 'stat' and 'statm' in an format that's easier
for humans to parse. If you type 'cat /proc/2246/status', you get something like:

bash-3.00# cat /proc/2246/status
Name:   gpm
State:  S (sleeping)
SleepAVG:       88%
Tgid:   2246
Pid:    2246
PPid:   1
TracerPid:      0
Uid:    0       0       0       0
Gid:    0       0       0       0
FDSize: 32
Groups:
VmSize:     1520 kB
VmLck:         0 kB
VmRSS:       340 kB
VmData:      148 kB
VmStk:        84 kB
VmExe:        60 kB
VmLib:      1196 kB
VmPTE:        12 kB
Threads:        1
SigQ:   1/4095
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000001000
SigCgt: 0000000008004202
CapInh: 0000000000000000
CapPrm: 00000000fffffeff
CapEff: 00000000fffffeff

The 'exe' pseudo-file is a simbolic link to the process command. Let us used another example,
if you are running a Xterm as process ID 23400, you can start another Xterm by typing /proc/23400/exe.

The 'maps' contains the current mapped memory regions and their access permission.
The 'root' display a copy of your root filesystem.

The 'environ' pseudo-file contains the environment for the process.
If you type '(cat /proc/23400/environ; echo) | tr "\000" "\n"' you get a lot of information about your system.

bash-3.00# (cat /proc/23400/environ; echo) | tr "\000" "\n"
CPLUS_INCLUDE_PATH=/usr/lib/qt/include
MANPATH=/usr/local/man:/usr/man:/usr/X11R6/man:/opt/kde/man:/usr/lib/qt/doc/man
HZ=100
SSH_AGENT_PID=1771
HOSTNAME=darkstar.example.net
SHELL=/bin/bash
TERM=linux
HUSHLOGIN=FALSE
QTDIR=/usr/lib/qt
USER=root
GDK_USE_XFT=1
SSH_AUTH_SOCK=/tmp/ssh-LsSuz13910/agent.13910
KDEDIR=/opt/kde
SESSION_MANAGER=local/darkstar:/tmp/.ICE-unix/28024
T1LIB_CONFIG=/usr/share/t1lib/t1lib.config
MINICOM=-c on
MAIL=/var/spool/mail/root
PATH=/usr/bin:/usr/sbin:/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin
:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/opt/kde/bin:/usr/lib/qt/bin
LC_COLLATE=C
INPUTRC=/etc/inputrc
PWD=/root
LANG=en_US
SHLVL=3
HOME=/root
LS_OPTIONS= --color=auto -F -b -T 0
LESS=-M
LOGNAME=root
LESSOPEN=|lesspipe.sh %s
DISPLAY=:0.0

Even though there are pseudo-files you cannot access by using a simple cat command, and other you can access at all, you can get more detailed information about the process by looking inside their proc ID folder. You can use some information about your process, or you can only look around your running process to know more about your system. If you find those info difficult to understand, try use only ps command. The ps command is going to simplificate info about processes.

Don't forget, know about your running processes is know about your machine and system. And also, don't forget to read the proc man pages.

Tutor_07: Proc Folder & Important Files

The above minitutor already talked about the /proc, but the only subject was about the processes, now it talks about some important files inside your proc folder.

The proc folder is like a filesystem inside the filesystem, used to restore and show data kernel, it means, inside /proc folder you have a lot of information about processes, hardware, drivers and more. From Proc Man Pages "/proc is a pseudo-filesystem which is used as an interface to kernel data structures rather than reading and interpreting /dev/kmem. Most of it is read-only, but some files allow kernel variables to be changed."

Inside the folder you can see several directories and files, those files are the subject of this minitutor and you must know everything about them, because they have a source of information about your system you need. Those files are common read by several commands and applications to get information to display, for example, system monitors like Gkrellm and Karamba.

The 'cmdline' file receives arguments passed to the Linux Kernel at boot time, it means this is the file you can read about all cheatcodes you are using. You can write any parameter during boot in this file, by using your boot manager or the boot prompt. We use scripts to to read this file looking for cheatcodes to start special services.

The 'cpuinfo' file is a collection of CPU and system architecture dependent items, where you can get information about your processor like model, model name cache size, vendor_id and more.

The 'devices' files list major numbers and devices groups, the 'dma' is a list of the ISA DMA (direct memory access) in use, the 'execdomains' a list of the execution domains, the 'fb' is the frame buffer information.

The 'filesystems' is a text list of the filesystems which were compiled into the kernel. This file is used b mount command to cycle through different filesystems when none is specified. It's a important file and let you know more about filesystems supported for your kernel.

The 'interrupts' file is used to record the number of interrupts per each IRQ on the i386 architecture, the 'iomen' is the I/O memory map, the 'ioports' is a list of currently registered Input-Output port regions that are in use, the 'locks' file shows current file locks and leases.

The 'meminfo' file, used by free command, report the amount of free and used memory, phisical and swap, on the system and also shared memory and buffers used by the kernel.

The 'mounts' is a list of all filesystems currently mounted, the 'modules' a list of the modules that have benn loaded by by the system, the 'mtrr' is the memory type range registers.

The 'partitions' file contains major and minor number of each partition as well as number of blocks and partition name, the 'slabinfo' list information about kernel caches, the 'stat' is the kernel/system statistics, the 'swaps' list swaps areas in use, the 'uptime' contains two number, the uptime of the system and the amoun of tim spent in idle process, both in seconds, and the 'version' identifies the kernel version.

As you can see above, those files are common read by several commands to get information about the system, the 'free' command for example reads info about memory on /proc/meminfo, the 'lsmod' gets info about kernel loaded modules on /proc/modules.

The Gkrellm and Karamba running on GoblinX get the info showed to you from these files inside proc folder. You can create your own scripts or applications to read and show information about your system by using those files, you can let the user know about some problems, some dangerous behaviors on his machine, or give to him source of information he can not find anywhere.

Understand, read and use the files inside proc folder is a good step to know better your system and your machine.

Tutor_08: Create and Delete Users

The Linux has a master of the system called 'root'. The root is the owner, the main user on the system, and has virtual access and control of everything, because of this power it is necessary create other users to retain the protection. Create an user is one of the very first step you must do and there is a command you can use called: useradd. Useradd is the command used to create a new user or update default new user information, and the command has some important options.

When the useradd command is invoked without '-D' option, it creaes a new user account using the values specified on the command line and the default values from the system, in fact you can type only 'useradd nameoftheuser' to create a new user account using default values and when is invoked with the '-D' option, it either display the default values or update values from command line. Another option you can use is '-d', to specify the user's login directory inside home dir using the user's login name as user directory, for example -d /home/goblix_home, the default is going to use the user's login name.

You can also set the expire_date of the user account by using '-e' option, set the number of inactive_days after password expires until the account is going to be disabled, 'f', the initial group name or number of the user's initial login group, '-g', a list of supplementary groups which the user is also a menber of, '-G'.

The '-m' option allows the useradd command to create the user's login directory for you, the '-s' specify the user's login shell, and you have a few more options.

An example of useradd command: useradd -m -c goblix -d /home/goblix_home -s '/bin/bash' goblix.
You can see the -m option to create the user's home, -c option to add a comment to the user's password, the -d option specifying the user's home directory and the '-s' option specifying the default shell, followed by the name of the user.

As you can see above, no password is set to the new user, you must use another command, the 'passwd'. The 'passwd' is the best way to set the password of the new user, just type 'passwd goblix' and then twice the password, and choose a good password using letters, number and symbols.

The /etc/passwd file has all user account information and /etc/group file the group information, you can specify the group of the new user and its supplementary groups. The '-G' option is important if you wish to add some groups to only few users, for example, you have a floppy group, it means only users added to this group can mount floppies. You can use a command like: 'useradd -m -c goblix -d /home/goblix_home -s '/bin/bash' -G floppy,cdrom goblix'. In the example the goblix user is going to have acess to cdroms and floppies, but you wish to enable groups to all users, it's better to use another important file called 'login.defs'.

Login.defs file, inside /etc folder, defines the site-specific configuration for shadow password suite and it's going to be subject to another minitutor, but in the example you can define groups to all users, like following example:

# List of groups to add to the user's supplementary group set when logging in on the console
# (as determined by the CONSOLE setting). Default is none.

CONSOLE_GROUPS floppy:audio:video:cdrom

The control of what you user can do it's very important. If you wish to use XServer and connect to internet, it's better create an user for this proposal instead of use root, because you will have more security.

If you wish to delete an user, you need to use 'userdel' command, just type 'userdel nameoftheuser' to remove the user, and if you wish also to remove the user's login home directory, type 'userdel -r namoeoftheuser', the '-r' option remove all files and also the user's home directory.

Create at least one user for your system, you need to have one to be more protected.

Tutor_09: Resize & Join Partitions

The Linux uses several filesystems types, such as ext2, ext3 and reiserfs, and those filesystems have an application prepared to let you resize a harddisk partition or partitions.

For ext2/ext3 partitions you need to use: resize2fs
From resize2fs manpage:
"The resize2fs program will resize ext2 file systems. It can be used to enlarge or shrink an ext2 file system located on device. The size parameter specifies the requested new size of the filesystem. If no units are specified, the units of the size parameter shall be the filesystem blocksize of the filesystem. Optionally, the size parameter may be suffixed by one of the following the units designators: 's', 'K', 'M', or 'G', for 512 byte sectors, kilobytes, megabytes, or gigabytes, respectively. The size of the filesystem may never be larger than the size of the partition. If size parameter is not specified, it will default to the size of the partition.

The resize2fs program does not manipulate the size of partitions. If you wish to enlarge a filesystem, you must first make sure you can expand the size of the underlying partition first. This can be done using fdisk(8) by deleting the partition and recreating it with a larger size."

For reiserfs partitions you need to use: resize_reiserfs
The idea behind both are the same, they are indicated you wish to resize an existent partition and not change the size of the partition.

You can notice we have cfdisk and fdisk application to resize and parted your harddisk, we will use in the example fdisk to join partitions and resize2fs to resize the filesystem.

Let's use an example.
Imagine you have two Linux partition on your system you wish to join, /dev/hda5 and /dev/hda6, you only can join partition if they are side by side in your harddisk. If you have doubt about it, type 'fdisk /dev/hda' and then type 'p' to see the End and Start of each partition. An example below:

  Disk /dev/hdb: 120.0 GB, 120060444672 bytes
  255 heads, 63 sectors/track, 14596 cylinders
  Units = cilindros of 16065 * 512 = 8225280 bytes
  
  Dispositivo Boot      Start         End      Blocks   Id  System
  /dev/hda1   *           1        7298    58621185   83  Linux
  /dev/hda2            7299       14024    54026595   83  Linux
  /dev/hda5           14025       14250     1815345   83  Linux
  /dev/hda6           14251       14596     2779245   83  Linux

The above example indicates you have two small partitions you wish to join. Imagine now in the /dev/hda5 you have three directories you use to store files, an example: images, documents, packages. And in the /dev/hda6 you have oldfiles, and newfiles.

You want to join these partition in one /dev/hda5, and you can do it without lose your files.
First you need to copy all directories found inside /dev/hda6 to /dev/hda5.
After copy all contents we are going to join these partitions, by using fdisk again. Type 'fdisk /dev/hda', then type 'd' to delete a partition, type '6', then again 'd' and type '5'. Don't worry about your files, we are only changing the harddisk table and not deleting files, but if you have doubts, test it before.
Now you need to join those partition, while inside fdisk type 'n' to create the new partition, then type '5', number of the first partition removed. After the step, type again 'p' to see if these partitions are joined in one.
The results must be:

  Disk /dev/hdb: 120.0 GB, 120060444672 bytes
  255 heads, 63 sectors/track, 14596 cylinders
  Units = cilindros of 16065 * 512 = 8225280 bytes
  
  Dispositivo Boot      Start         End      Blocks   Id  System
  /dev/hda1   *           1        7298    58621185   83  Linux
  /dev/hda2            7299       14024    54026595   83  Linux
  /dev/hda5           14025       14596     4594590   83  Linux

After you see the results, type 'w' to realocate partitions. You have now a new parition created by join the previous /dev/hda5 and /dev/hda6, but you don't have the filesystem, to create it we will use resize2fs.

Just type 'resize2fs /dev/hda5' and your filesystem will be resized to fit your new partition. Without any parameter the resize2fs will fit all partition space, but you have the option to indicate the size of the new resized filesistem by using 'resize2fs /dev/hda5 size', or if you want a reiserfs partition instead of ext2, 'resize_reiserfs /dev/hda5' or a differente size 'resize_reiserfs -s size /dev/hda5'. You now have a new partition resized and with your contents of older to partitions.

If you have some important files, it's better test the minitutor on some not important partitions to see if it works ok for you.
This Minitutor is based on a article written by Diniz Fernando Bortolotto Ferreira and published by Dicas-l.com.br. Original article [Portuguese]: http://www.dicas-l.com.br/dicas-l/20060416.php

Tutor_10: Chown & Chgrp

The Linux user when just start to use the system will try to learn more and more about the system and its application, in this search of knowledge, the user is going to find several opinion and warning about not use 'root' to do some tasks like browse the internet... The first step when you installed a Linux distro is change the root password and create a new user.

After create a new user without root power, you need to know some basic commands such as Chown and Chgrp.

From Chown Man Page:
Chown changes the user and/or group ownership of each given file, according to its first non-option  argument,  which is interpreted as follows. 

The GNU chown command you will use during all your Linux days and you must know its options because change ownership of files and directories are definitively a daily job. Chown main syntax to use is 'chown username:usergroup file'. The example changes the ownership and also the group of the file. The first item given is the username, if you only use 'chwon user file.txt', you only change the user of the file.txt, but if you use 'chown user:group file.txt'.

There are some good options to use with chown, a very praticle one is '-R' option, or '--recursive' which is used to change the ownership of files and directories recursively, and example 'chown goblix /home'.  There are options to control the verbosity of the command if you wish to know more information, such as '-c', that reports only when a change is made, and '-v', that output a diagnostic for every file processed.

Imagine the following scenary, you have an user called goblix, and also root, and you create another one called theuser,  now you wish to copy some files ownered by goblix to /home/theuser,  but those files are in one folder full of files ownered by others users, for that you can use the option '--from'. This option will only change the ownership of files ownered by the given user in the command, an example 'chown -R --from=goblix theuser /etc'.

The Chgrp works exactly the same, but it changes the group ownership of a file, for example 'chgrp users file.txt' is going to change the group of the file to users.  Some options used with chown also are applicable with chgrp command such as -R, -v, -h, -c, but the '--from' option are not applicable.

These commands are very usefull and you will use them, specially chown command. You will need to use files ownered by root logged as user and in order to edit these files you need to change the mode or, better, change the ownership of them, and chown is there for you.

Tutor_11: Change Process Priority

It could often happen that moment to change the priority of runnings process, or start a command with an adjusted niceness, and for those moments you can use 'nice' and 'renice'.

All Linux processes work with priorities from -20 to +20, being -20 the major priority, and root have control over the above scale, all though common users only can set priority from 0 to +20.
The first command of this family is 'nice'. Nice is used to run command with an adjusted niceness, which affects process scheduling. Nicenesses range from -20 (most favorable scheduling) to 19 (least favorable).

The basic sintaxe is: nice [OPTION] [COMMAND [ARG]...].

For example 'nice -n 12 leafpad text'  is going to start leafpad, open a file called text with priority set to +12. The arguments must be the last entry because they refer to the command to be executed and not to nice, you do not need any argument or neither to set the niceness, by default nice uses +10.

The second command of the family is 'renice'.

From Renice Man Pages:
Renice alters the scheduling priority of one or more running processes. The following who parameters are interpreted as process ID's, process group ID's, or user names.  Renice'ing a process group causes all processes in the process group to have their scheduling priority altered. Renice'ing a user causes all processes owned by the user to have their scheduling priority altered.  By default, the processes to be affected are specified by their process ID's.

As you can see, if you wish to start a process and set its niceness you need to use 'nice', but if you wish to change the priority of a running process, you will use 'renice'.

The basic sintaxe is: renice priority [[-p] pid ...] [[-g] pgrp ...] [[-u] user ...].
The '-u' option is used to indicate user of running process to modify, '-p' the pid of the process, and '-g' process group pid. An example 'renice +1 987 -u daemon root -p 32' would change the priority of process ID's 987 and 32, and all processes owned by users daemon and root.

Let's pratice and understand. You desire to change the priority of the 'crond' process, first you need to know the PID of crond process, you can type 'ps -C crond' to get the PID, an example '5124' as PID. After get the PID, you need to know its priority, you can use 'top' command to know it, type 'top -p 5124', you will see several columns and values, the 'NI' column indicates the priority number set by nice, in the example '0'. Now you can use, for example, 'renice -2 5124' to change the priority to '-2', or a better scheduling priority.

These commands are very usefull in several ocasions, mostly when a better performance are necessary, however they must be carrefully used because change the priority to a high value like '-18' or '-19' can decrease the performance and make the system works slowly. Before you adventure yourself on changing priority process, it's better know more about these commands.

Tutor_12: Adjust Tunable Filesystem Parameters

System administrator, or carrefully users, can adjust verious tunable filesystem parameters on Linux filesystems in order to get better performance, and they have tunning applications for every Linux filesystem, for example, tune2fs for ext2/ext3 filesystems, jfs_tune for jfs and reiserfstune for reiserFS.

Tune2fs is the tunning tool for ext2/etx3 filesystems and can be used to adjust tunable filesystem parameters.

The first option of tune2fs is used to adjust the maximal count between two filesystem checks.
The '-c' option is important because any Linux system must check sometimes the partition and its filesystem. You can disable all checks by set max-mount-counts to 0 or -1, but you should strongly consider the consequences of disabling mount-count-dependent. The filesystem must be checked from time to time because bad disk drives, cables, memory, and kernel bugs could all corrupt a filesystem without marking the filesystem dirty or in error. If you use 'tune2fs -c 10 /dev/hda2' after ten mount-counts the filesystem will be checked.

Another option you can use in order to postoponed or accelerate the next filesystem check is '-C'.
The '-C' option set the number of times the filesystem has been mounted. You can use with -c to force an fsck on the filesystem at the next boot, for example 'tune2fs -c 10 -C 9 /dev/hda2'.

You can also change the error behavior. It's an important option if you wish to force a remount of kernel panic, in all cases, a filesystem error will cause e2fsck(8) to check the  filesystem  on the next boot, but if you set the '-e' option to remount-to or panic, instead of continue, you will have the filesystem boot stopped.
You can override another error, this time errors while tunning the filesystem with option '-f'.

As you can see above, you can specify all many times your filesystem will be mounted before it's checked, but you can also specify certain period of time, such as days, weeks and months, with '-i' option. It is strongly recommended that either -c  (mount-count-dependent)  or -i (time-dependent) checking be enabled to force periodic full e2fsck(8) checking of the filesystem.  An example 'tune2fs -c 10 -i 1w /dev/hda2'.

Some more important options are '-j', to add an ext3 journal to the filesystem, '-J' to override the default ext3 journal parameters, '-l' to list the contets of a filesystem block, '-L' to set a volume label, '-m' to reserve blocks percentage, '-u' set the user who can use reserved blocks, '-U' set the unique identifier, and more.

You can also use the option '-o' to change the default mount options from /etc/fstab by using tune2fs.

For some reasons if you disable the periodic filesystem check, you need to use tune2fs to reconfigure the check periodic. Never stop all filesystem checks, because an error or a bad block can damage your harddisk forever. If you do not wish to check your filesystem every boot, change your init scripts, and try use tune2fs to reconfigure options used by fsck. If you often need to reboot your computer, you can use tune2fs to set a long period between checks, but do not forget also to use the time-dependent option.

It often necessary checks the filesystem, if you have two or three partition and use one a lot more than the other, because while you are using a partition the others are mounted, in the next boot from the less used filesystem.

Use tune2fs to tunable your filesystem parameters to get better performance of your filesystem and better control of errors. Try read the manpage to know more about the options.