A simple approach to tackle the problem of growing need of partition is to use the links to share which has excess space. It happens many times in IT environment that the disk which is having the running application runs out of space. But at the same time we have many partitions whose space is underutilized.

Example:
We have one /app partition of 200 GB but it is already 90% full. Application team is demanding 100 GB extra on the same partition. At the same time we have /extra partition of 250 Gb with current space utilization of 50 GB only. So without disturbing the current setup we can allocate the space which is there in /extra to /app by creating a sym link.

process is simple create a sub directory in /extra and do the linking:

# mkdir /extra/app; ln -s /extra/app /app

However if you have a large number of sym links the task of space management will become a bit tough. Normal team will not be aware how this stuff works but still overall space allocation will always depend on these sym links as well. But this is very good temporary change which you can make untill the things are sorted out.

DHCP : DHCP stands for Dynamic Host Configuration Protocol and is an Internet protocol for automating the configuration of computer’s IP that use TCP/IP protocol. DHCP can be used to automatically assign IP addresses, to deliver TCP/IP stack configuration parameters such as the subnet mask and default router, and to provide other configuration information such as the addresses for printer, time and news servers.

Setting up DHCP server
Step 1) Editing the /etc/dhcp.conf File

Explanation: When DHCP service/protocol starts it firstly reads the file /etc/dhcp.conf. Normally you can find a sample copy of dhcpd.conf in the following directory which you can always use as a guide and configuration base.

/usr/share/doc/dhcp-/dhcpd.conf.sample

Here is a quick explanation of the dhcp.conf file: Most importantly, there must be a “subnet” section for each interface on your Linux box.

{

ddns-update-style interim;
ignore client-updates;

subnet 192.168.0.0 netmask 255.255.255.0

# — default gateway
option routers 192.168.0.1;
option subnet-mask 255.255.255.0;

option nis-domain “sharetab.com“;
option domain-name “sharetab.com“;
option domain-name-servers 192.168.1.1;

option time-offset -18000; # Eastern Standard Time
# option ntp-servers 192.168.1.1;
# option netbios-name-servers 192.168.1.1;
# — Selects point-to-point node (default is hybrid). Don’t change this unless
# — you understand Netbios very well
# option netbios-node-type 2;

range dynamic-bootp 192.168.0.128 192.168.0.254;
default-lease-time 21600;
max-lease-time 43200;
“/etc/dhcpd.conf.backup” 31L, 852C

}

Note:- Changing Values are indicated in Red

Step2) Starting the dhcp service manually with commands

# chkconfig dhcpd on

# service dhcpd restart

Comment on this entry if you face any problem in DHCP configuration

Continuing with last article on “how to take backup of SSL certificate” this wrticle shows how to export the certificates.

Exporting certificate:
1. Go to “run” and type “MMC” and hit enter.
2. As per previous article, add snap-ins. After adding the snap-in, just expand it and go to “Personal->Certificates” section.

2. Right click on the listed certificate and click on “All Tasks”, click on export. New export wizard will open, choose whether to use encryption or not and follow the steps. Choose the file extension and other applicable option for the export.
3. Set password to the “.pfx” file and choose finish.

You have successfuly exported the certificate which can be imported later. Please subscribe to our feeds or add this site in your bookmarks to pay future visit.

This is just an example which I am taking, I am not sure with functioning of all, but it surely worked for taking backup of SSL certificate on my server. The process is small and simple.

Taking Backup of certificates:
1. Click “START / WINDOWS” on your desktop and click on “run”. Type “MMC” and hit enter.

2. Click on “Add/Remove snap-in” followed after click on “File” menu.
3. On new window, click on “Add” followed by selection of “certificate” which you want to backup.

4. Click add again, select computer account and click “finish”.

You can list the certificate you have backed up in “MMC” window as “Snap-Ins Added to” section.
You can save this MMC certificate for later use by duplicating it at some other location. Follow screenshots for details.

Next article will be demonstrating on how to restore the backed up certificates. If this is your first visit, please subscribe to our feed or bookmark the webpage to keep a track on all new articles.

The command used for this purpose is “isainfo” which is then used in different combinations to get the system information. For all valid option use “# man isainfo”.

# isainfo -kv

the above command will show you the number of kernel bits. You can also use “-v” option with combination of “-k or -b”. Below is the screenshot for the above command in different form. Older version of solaris were running on 32 bit architecture and were not having “isainfo” command.

Changing timezone is different on x86 machines and on Solaris servers. I have listed the steps for both platforms below.

Solution for Solaris 10 x86:
As changing TimeZone on Solaris machine requires reboot, so plan a downtime and then plan the change activity. If one is changing only time, then one can use date command with required options. Also point to note here in both cases is that, changing time only, does not require reboot where as you would have to reboot the Solaris machine in case of changing TimeZone.

Changing TimeZone is 3 step process as listed below:

Issue “date” command to check which TimeZone you are currently in according to system.

# date
Thu Apr 23 20:16:13 IST 2009
#

1. Change the TimeZone entery in /etc/TIMEZONE file for the field of TZ

# TZ=US/Pacific (for PDT or any other format for specific TimeZone.)

One can list all TimeZones in directory : /usr/share/lib/zoneinfo.

2. Use following commands for changing TimeZone:

# rtc -z US/Pacific
# rtc -c
#

3. Reboot the system and after system is up and running issue the “date” command and check for the changes.

This is the output which I got on my machine:

Sun Microsystems Inc.   SunOS 5.11      snv_79a January 2008
# date
Thu Apr 23 20:47:23 PDT 2009
#

For Solaris 10 server:

On server there is only one change which has to be done. Just cahnge /etc/TIMEZONE file and edit TZ entry to proper TimeZone and reboot the server. Changes will be apparent after the reboot.

Please leave a feedback and subscribe to feeds for more updates for any query. HAPPY SURFING. [:D]

HP-UX file system structure is like an inverted tree with the root of the tree at the top and branches and leaves connected to it toward its bottom. The top level is root and represented by the forward slash (/) character. When you install HP-UX Operating Environment, seven file systems are created, by default. These are /, /stand, /var, /usr, /tmp, /opt and /home.

Some of these directories contain static data which refers to file contents that are usually not modified while some holds dynamic or variable data which refers to file contents that are modified when required.

The Root file system (/): The root file system contains many higher level directories which hold specific information. Some of the important directories under the root are:

The Binary directory (/bin): This directory contains user executable commands. It is linked to /usr/bin directory. /bin directory holds static data.

The device directory (/dev): This directory contains files for hardware devices. There are two types of device files ‘block special device files’ and ‘character special device files’ (Raw device files) some important sub-directories under /dev are: dsk, rdsk, rmt, pts and vg00. The /dev directory contains static data files.

The Library Directory (/lib): This directory contains shared library files which are required by programs. The /lib directory can also be accessed using /usr/lib directory since both are linked. The /lib directory contains static data.

The system Binary Directory (/sbin): The most commands required at system boot up and commands that require boot privileges to run are located in this directory. The /sbin directory contains static data.

The Etcetera directory (/etc): This directory holds most system configuration files. Some of the important sub-directories under /etc are rc.config.d, default,opt, dt,ftpd,lp, lvmconf,mail, sam, skel and vx. The /etc directory contains static data.

The lost+found directory (lost+found): This directory contains files that become orphan after system crash. Orphan file is that which has lost its name. This directory is automatically created when the file system is created.

The Net directory (/net): If autofs is used to mount NFS file systems using special map, all available NFS file systems on the network are mounted beneath /net directory.

The Kernel file system (/stand): The kernel files are located in /stand file system. Files that contain kernel code, boot device information, kernel parameters and module information are stored here. This directory is altered only when kernel update is required.

The Variable file System (/var): This directory contains frequently changing data while system is up and running. Files holding log, spool, status and other dynamic data. Some important sub directories under /var are /var/adm, /var/dt, /var/mail, /var/spool, /var/tmp, /var/opt

The UNIX System Resource file system (/usr): This directory contains general files related to system. Some important sub-directories under /usr are /usr/sbin, /usr/local, /usr/include, /usr/share, /usr/lib.

The Temporary file System (/tmp): This file system contains temporary files. Temporary files are created by programs when they run. These files get removed after system reboot.

The Home file system (/home): This file system is used to hold users home directories. Whenever a user account is created, it assigns home directory for that user to keep his  personal files. No other user can access other user’s home directory.

prtconf : This command is used to display configuration information, inclusding the total amount of memory and deviced configured on system as per system’s hierarchy. This also verifies whether any device has been seen/recognised by system or not.
Note : The output of prtconf command can vary depending on the version of the host system’s PROM.

sysdef : This command displays device configuration defination which also includes system’s hardware, psuedo devices, selected kernel parameteres and loadable modules.

dmesg : This command displays system diagnostic messages as well as list the devices attached to the system after the resent restart.

format : The format command displays both physical and logical device names for all available disks. You can select the device/disk number and further format it and allocate space according to your need.

cfgadm : This command lists all configured/unconfigured devices on host system.

FUNCTIONS OF DIFFERENT KEYS

i :- enter in insert mode and inserts the data before cursor position.
I :- move the cursor at the beginning of line and inserts the data before cursor position.
a :- enter in append mode and appends the data after cursor position.
A:- move the cursor at the end of the line and appends the data after cursor position.
o :- create the blank line before cursor position and allows to insert the data.
O :- creates the blank line above cursor position and allows to insert the data.
^ :- shifts the cursor at the beginning of the line (without insert mode)
$ :- shifts the cursor at the ending of the line ( without insert mode)
H :- moves the cursor to the first character of the first line of the screen.
M :- moves the cursor to the first character of the middle line of the screen
Ctrl E :- scroll up line wise.
Ctrl Y :- scroll down line wise.
Ctrl U :- scroll up half window.
Ctrl D :- scroll down  half window
Ctrl F :- scroll a screen in forward direction.
Ctrl B :- scroll a screen in reverse direction.
w :- moves the cursor at the beginning of next word.
e :- moves the cursor at the ending of next word .
b :- moves the cursor at the beginning of previous  word.
G :- moves the cursor at the end of file.
x :- deletes the single character.(similar to DEL).
nx :- deletes “n” no. of character from current cursor position.
X :- deletes a single character (similar to DEL)
dw :- deletes the word from current cursor position.
ndw :- deletes the “n” words from current cursor position.
dd :- deletes the line.
ndd :- deletes the “n”lines from current cursor position.
Y:- yanking or copying of lines.
p:- pastes yanked(copied)lines.
:set nu :- to set the temporary line number to the file contents.
:set nonu :- to unset the temporary line number of the file contents.
:set showmode :- it displays various modes of operation of vi editor such as insert mode append  mode etc.
:set noshowmode :- it unset “set showmode” effects from VT editor.
:n:- to go to particular line no for “n” refer to specific line no.
:$:- moves the cursor at the end of file (similar to G)
/<word to search> :- to search the word in the file.
q :- to quit the file without saving the changes.
wq:- to save the changes and quit the file.
:4d:- to delete forth line
:2,4d:- to delete 2 to 4 lines.
:3 co 6:- to copy line no3 and paste after line number 6.
:2,4 co 6:- to copy lines 2 to 4 and paste after line number6.
:3 mo 6:- to move line number3 after line number6.
:2,4 mo 6:- to move lines 2 to 4 and paste after line number 6.
:4,6 w >> /<destination_filename>:- it writes lines 4 to 6 from currently opened file and appends the data in the destination file.
:2,6 w/<new file name>:- it creates new file and writes lines 2 to 6 from currently opened file to it.
r:- to replace single character.
cw:- to change single word.
:!<os command>:- to run OS command while running Vi editor.

It is a common editor present in every unix flavor. It is pronounced as “Vee Eye” commonly called as visual editor.
Visual editor has three basic modes as follows.

1) Insert mode
a) append mode
b) open mode
c) replace mode
d) change mode
2) Command mode
3) Execution mode

1) Insert mode:  In this mode VI editor accepts all input.To enter in this mode, we have to use keyboard key ( i ) and go out from this mode,we have to use (esc) key.

2) Command mode:  In this mode we can perform various operations such as saving the contents,quitting the editor,saving and quitting,copying and pastig the data,moving the data etc.

cursor movements
left direction :h
right direction : l
up direction : k
down direction: j

3) Execution mode: In this mode, we can perform various operations such as saving the contents,quiting the editor,saving and quiting,copying and passing the data,moving the data etc.