10 good reasons why you should install Gnu/linux

10 good reasons why you should install Gnu/linux, In the end, you can decide for yourself whether they're reason enough to migrate from other operating systems.

 1: Viruses/malware

This reason is always at the top of my list. Sometimes we don't focus on the things about the virus/malware while installing unknown software or inserting flash drive in USB, you can't know where they're getting those applications or attachments from. You can make sure those machines have antivirus and anti-spyware, but why even take the chance? When you are using the Gnu/Linux operating system, this concern becomes moot.

 

2: Security

This can be summed up easily. If you don't give any one the root password, they can't run with root privileges. Of course, you hit a little snag when using a distribution like Ubuntu. For any sudo-based operating system, you will need to edit the /etc/sudoers file to give user privileges they need.

 

3: Cost effectiveness

Let's say you have a younger user who is getting a hand-me-down machine that needs an OS reinstall. If you don't have that copy of Windows around, you're stuck purchasing a new copy. This can also be applied to any number of applications you might have to pay for. Avoid these costs altogether by handing that child the same machine running Gnu/Linux. You won't have pay for the OS license or any application that child might need or want. On top of that, they'll have the Add/Remove Software tool ,where they can hunt around and find just about anything they would need... all on their own! You can also run a modern distribution on much less hardware than you will need for Vista or Windows 7.

 

4: Age-specific tools

Did you know there are distributions/software groups designed specifically for young adults and children? There is Sugar, geared for K-6, Edubuntu, for ages 3-18, LinuxKidX, for ages 2-15, Foresight Kids, for ages 3-12, and many others. These age-specific tools are well suited for the group they target with graphics and language tuned for the age range. And some of the distributions geared specifically for younger kids lock the operating system down tightly so that only certain tasks can be run.

 

5: Netbooks / Low-end configuration devices

The Gnu/Linux operating system can run on low configuration devices and netbooks. You can install either a full-blown OS or a netbook-specific OS, along with whatever software you need on the netbook, making it an excellent choice for you. Gnu/Linux runs with no lag on low configuration or old Pc's. Puppy Linux can run on 333MHz CPU and 64MB Disk Spac. However having 256MB RAM and a 512MB swap file is more realistic.

 

6: Agile learners

If you put a Linux-based machine in front of a young user, you won't hear complaints like, "Why can't it run Quicken!" or "I need my custom payroll app to run on this!" Most of the people will master the Linux operating system quickly (and adroitly), with a minimal learning curve. Young minds adapt so well, you won't have any trouble adjusting to any differences. You could probably sit with a Gentoo box running CDE or AfterStep and in less time it took you to know what Linux means.

 

7: Staying in step

I know this one will bring out the ire in many readers. I'm not saying any operating system is used more than any other. But Linux is used worldwide. Many countries as a whole have adopted Linux. The future of Linux is very bright — and it seems to be getting brighter. So why not give you a head start on what could possibly be the future of the PC? This also applies for those fledgling IT pros out there. If Windows is so user friendly, you spending most of their time on Linux should have no problem grasping Windows. Gnu/Linux passes 1600 Games which competes with windows in gaming. In fact, I would argue that it will enhance the your ability to fully grasp the operating system and how the PC really works.

 

8: Learning opportunities

Open source emboldens education. It practically screams, "Open me up and learn!" What better way to help youngsters learn than by giving them the ability to do just that? With really curious people, the desire to learn is extraordinary — so why lock them down with closed source software? When a people is exposed to open source software and an open source operating system, the educational opportunities are limitless.

 

9: A lesson in community

Teaching you the value of open source software helps them understand community. Although you aren't likely to open up the source code of the applications they're using, in today's constantly evolving, community-driven world, they need every advantage they can get as they grow up. Having a sound understanding of open source will help them to understand, at an early stage, what it means to really work with and for a team. Using Linux indirectly teaches you the benefit of volunteering — something many of us need to learn more about. 

10: Content filtering

Linux has numerous ways to handle content filtering for you. From the manual editing of the /etc/hosts file, you can filter content in Linux far more granularly than you can in Windows — and just as easily. Add to this the ability to lock down what you can and can't do (without having to add third-party software), and Linux quickly becomes a safe computing environment for you.

 

Your take

Would you trust your security with Linux? Do you think Linux could help — or hinder — your learning on a PC? Which operating system do you think is the best choice for you? Linux? Windows? OS X? Join the discussion and share your thoughts.

MediaTek announces open-source development platform for IoT devices

MediaTek Labs has announced the launch of the MediaTek LinkIt Smart 7688, a development platform enabling rapid development of advanced Wi-Fi based devices such as IP cameras, surveillance devices, smart appliances and Wi-Fi gateways that make use of cloud services.

Two versions of the platform's hardware development kit (HDK) are available: the LinkIt Smart 7688, which includes a microprocessor unit (MPU) based on the MediaTek MT7688AN system-on-chip (SOC), and the LinkIt Smart 7688 Duo, which in addition to the MPU includes a microcontroller unit (MCU) and is Arduino compatible. Both development boards feature built-in Wi-Fi, 128MB RAM and 32MB flash, and a wide variety of options for connecting peripherals.

The MediaTek LinkIt Smart 7688 and 7688 Duo development boards are available to ship globally. The LinkIt Smart 7688 costs US$12.90, while the LinkIt Smart 7688 Duo costs US$15.90. A fully open-source version of the Wi-Fi driver is in development and expected to be made available by MediaTek Labs in the coming months, the company added. 

"MediaTek Labs is focused on stimulating innovation in IoT and is pleased to extend its LinkIt family of development platforms to the open-source and web developer communities, enabling broader product development for a more connected world," said Marc Naddell, VP of MediaTek Labs. 

"The new LinkIt Smart 7688 development platform will appeal to a wide range of developers because of its open-source software compatibility, support for several popular programming languages and use of Linux."

10 Linux GUI tools for sysadmins

Has administering Linux via the command line confounded you? Here are 10 GUI tools that might make your life as a Linux administrator much easier.

If you're a system administrator, it's reached a point where Linux has become a must-know. This is especially true when you're working in a larger environment. Many organizations have migrated from Windows, where everything is managed with a point-and-click GUI. Fortunately, Linux has plenty of GUI tools that can help you avoid the command line (although every serious sysadmin should become familiar with the commands).

What are some good GUI tools that can simplify your Linux sysadmin tasks? Let's take a look at 10 of them.

1: MySQL Workbench

MySQL Workbench is one of my favorite tools for working with MySQL databases. You can work locally or remotely with this well designed GUI tool. But MySQL Workbench isn't just for managing previously created databases. It also helps you design, develop, and administer MySQL databases. A newer addition to the MySQL Workbench set of tools is the ability to easily migrate Microsoft SQL Server, Microsoft Access, Sybase ASE, PostgreSQL, and other RDBMS tables, objects, and data to MySQL. That alone makes MySQL Workbench worth using.

2: phpMyAdmin

phpMyAdmin is another MySQL administration tool... only web based. Although it doesn't offer the bells and whistles of MySQL Workbench, it's a much more user-friendly tool. With phpMyAdmin you can create and manage MySQL databases via a standard web browser. This means you can install phpMyAdmin on a headless Linux server and connect to it through any browser that has access to the machine.

3: Webmin

Webmin is a web-based one-stop-shop tool for administering Linux servers. With Webmin you can manage nearly every single aspect of a server—user accounts, Apache, DNS, file sharing, security, databases, and much more. And if what you need isn't included with the default installation, a massive number of third-party modules are available to take up the slack.

4: YaST

YaST stands for Yet Another Setup Tool. It enables system configuration for enterprise-grade SUSE and openSUSE and serves as both the installation and configuration tool for the platform. With YaST you can configure hardware, network, and services and tune system security, all with an easy-to-use, attractive GUI. YaST is installed by default in all SUSE and openSUSE platforms.

5: Shorewall

Shorewall is a GUI for configuring iptables. Yes, there are other GUIs for tuning the security of your system, but many of them don't go nearly as deep as Shorewall. Where an app like UFW is one of the best security tuners for the desktop, Shorewall is tops for the server. With this particular security GUI, you can configure gateways, VPNs, traffic controlling, blacklisting, and much more. If you're serious about your firewall, and you want a GUI for the job, Shorewall is what you want.

6: Apache Directory

Apache Directory is about the only solid GUI tool for managing any LDAP server (though it is designed particularly for ApacheDS). It's an Eclipse RCP application and can serve as your LDAP browser, schema editor, ApacheDS configuration editor, LDIF editor, ACI editor, and more. The app also contains the latest ApacheDS, which means you can use it to create a DS server in no time.

7: CUPS

CUPS is the Linux printer service that also happens to have a web-based GUI tool for the management of printers, printer classes, and print queues. It is also possible to enable Kerberos authentication and remote administration. One really nice thing about this GUI is its built-in help system. You can learn nearly everything you need to manage your print server.

8: cPanel

cPanel is one of the finest web-based administration tools you'll use. It lets you configure sites, customers' sites and services, and quite a bit more. With this tool you can configure/manage mail, security, domains, apps, apps, files, databases, logs—the list goes on and on. The only drawback to using cPanel is that it's not free. Check out the pricing matrix to see if there's a plan to fit your needs.

9: Zenmap

Zenmap is the official front end for the Nmap network scanner. With this tool, both beginners and advanced users can quickly and easily scan their network to troubleshoot issues. After scanning, you can even save the results to comb through them later. Although you won't use this tool to directly administer your system, it will become invaluable in the quest for discovering network-related issues.

10: Cockpit

Cockpit was created by Red Hat to make server administration easier. With this web-based GUI you can tackle tasks like storage administration, journal inspection, starting/stopping services, and multiple server monitoring. Cockpit will run on Fedora Server, Arch Linux, CentOS Atomic, Fedora Atomic, and Red Hat Enterprise Linux.

50 Most Frequently Used Gnu/Linux Commands

This article provides practical examples for 50 most frequently used commands want to become a sysadmin in Gnu/Linux.

This is not a comprehensive list by any means, but this should give you a jumpstart on some of the common Gnu/Linux commands. Bookmark this article for your future reference.

1. tar command examples

Create a new tar archive.

$ tar cvf archive_name.tar dirname/

Extract from an existing tar archive.

$ tar xvf archive_name.tar

View an existing tar archive.

$ tar tvf archive_name.tar

2. grep command examples

Search for a given string in a file (case in-sensitive search).

$ grep -i "the" demo_file

Print the matched line, along with the 3 lines after it.

$ grep -A 3 -i "example" demo_text

Search for a given string in all files recursively

$ grep -r "ramesh" *

3. find command examples

Find files using file-name ( case in-sensitve find)

# find -iname "MyCProgram.c"

Execute commands on files found by the find command

$ find -iname "MyCProgram.c" -exec md5sum {} \;

Find all empty files in home directory

# find ~ -empty

4. ssh command examples

Login to remote host

ssh -l jsmith remotehost.example.com

Debug ssh client

ssh -v -l jsmith remotehost.example.com

Display ssh client version

$ ssh -V
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003

5. sed command examples

When you copy a DOS file to Unix, you could find \r\n in the end of each line. This example converts the DOS file format to Unix file format using sed command.

$sed 's/.$//' filename

Print file content in reverse order

$ sed -n '1!G;h;$p' openupdates.txt

Add line number for all non-empty-lines in a file

$ sed '/./=' openupdates.txt | sed 'N; s/\n/ /'

6. awk command examples

Remove duplicate lines using awk

$ awk '!($0 in array) { array[$0]; print }' temp

Print all lines from /etc/passwd that has the same uid and gid

$awk -F ':' '$3==$4' passwd.txt

Print only specific field from a file.

$ awk '{print $2,$5;}' employee.txt

7. vim command examples

Go to the 143rd line of file

$ vim +143 filename.txt

Go to the first match of the specified

$ vim +/search-term filename.txt

Open the file in read only mode.

$ vim -R /etc/passwd

8. diff command examples

Ignore white space while comparing.

# diff -w name_list.txt name_list_new.txt

2c2,3
< John Doe --- > John M Doe
> Jason Bourne

9. sort command examples

Sort a file in ascending order

$ sort names.txt

Sort a file in descending order

$ sort -r names.txt

Sort passwd file by 3rd field.

$ sort -t: -k 3n /etc/passwd | more

10. export command examples

To view oracle related environment variables.

$ export | grep ORACLE
declare -x ORACLE_BASE="/u01/app/oracle"
declare -x ORACLE_HOME="/u01/app/oracle/product/10.2.0"
declare -x ORACLE_SID="med"
declare -x ORACLE_TERM="xterm"

To export an environment variable:

$ export ORACLE_HOME=/u01/app/oracle/product/10.2.0

11. xargs command examples

Copy all images to external hard-drive

# ls *.jpg | xargs -n1 -i cp {} /external-hard-drive/directory

Search all jpg images in the system and archive it.

# find / -name *.jpg -type f -print | xargs tar -cvzf images.tar.gz

Download all the URLs mentioned in the url-list.txt file

# cat url-list.txt | xargs wget –c

12. ls command examples

Display filesize in human readable format (e.g. KB, MB etc.,)

$ ls -lh
-rw-r----- 1 ramesh team-dev 8.9M Jun 12 15:27 arch-linux.txt.gz

Order Files Based on Last Modified Time (In Reverse Order) Using ls -ltr

$ ls -ltr

Visual Classification of Files With Special Characters Using ls -F

$ ls -F

13. pwd command

pwd is Print working directory. What else can be said about the good old pwd who has been printing the current directory name for ages.

14. cd command examples

Use “cd -” to toggle between the last two directories

Use “shopt -s cdspell” to automatically correct mistyped directory names on cd

15. gzip command examples

To create a *.gz compressed file:

$ gzip test.txt

To uncompress a *.gz file:

$ gzip -d test.txt.gz

Display compression ratio of the compressed file using gzip -l

$ gzip -l *.gz
         compressed        uncompressed  ratio uncompressed_name
              23709               97975  75.8% asp-patch-rpms.txt

16. bzip2 command examples

To create a *.bz2 compressed file:

$ bzip2 test.txt

To uncompress a *.bz2 file:

bzip2 -d test.txt.bz2

17. unzip command examples

To extract a *.zip compressed file:

$ unzip test.zip

View the contents of *.zip file (Without unzipping it):

$ unzip -l jasper.zip
Archive:  jasper.zip
  Length     Date   Time    Name
 --------    ----   ----    ----
    40995  11-30-98 23:50   META-INF/MANIFEST.MF
    32169  08-25-98 21:07   classes_
    15964  08-25-98 21:07   classes_names
    10542  08-25-98 21:07   classes_ncomp

18. shutdown command examples

Shutdown the system and turn the power off immediately.

# shutdown -h now

Shutdown the system after 10 minutes.

# shutdown -h +10

Reboot the system using shutdown command.

# shutdown -r now

Force the filesystem check during reboot.

# shutdown -Fr now

19. ftp command examples

Both ftp and secure ftp (sftp) has similar commands. To connect to a remote server and download multiple files, do the following.

$ ftp IP/hostname
ftp> mget *.html

To view the file names located on the remote server before downloading, mls ftp command as shown below.

ftp> mls *.html -
/ftptest/features.html
/ftptest/index.html
/ftptest/othertools.html
/ftptest/samplereport.html
/ftptest/usage.html

20. crontab command examples

View crontab entry for a specific user

# crontab -u john -l

Schedule a cron job every 10 minutes.

*/10 * * * * /home/ramesh/check-disk-space

21. service command examples

Service command is used to run the system V init scripts. i.e Instead of calling the scripts located in the /etc/init.d/ directory with their full path, you can use the service command.

Check the status of a service:

# service ssh status

Check the status of all the services.

service --status-all

Restart a service.

# service ssh restart

22. ps command examples

ps command is used to display information about the processes that are running in the system.

While there are lot of arguments that could be passed to a ps command, following are some of the common ones.

To view current running processes.

$ ps -ef | more

To view current running processes in a tree structure. H option stands for process hierarchy.

$ ps -efH | more

23. free command examples

This command is used to display the free, used, swap memory available in the system.

Typical free command output. The output is displayed in bytes.

$ free
             total       used       free     shared    buffers     cached
Mem:       3566408    1580220    1986188          0     203988     902960
-/+ buffers/cache:     473272    3093136
Swap:      4000176          0    4000176

If you want to quickly check how many GB of RAM your system has use the -g option. -b option displays in bytes, -k in kilo bytes, -m in mega bytes.

$ free -g
             total       used       free     shared    buffers     cached
Mem:             3          1          1          0          0          0
-/+ buffers/cache:          0          2
Swap:            3          0          3

If you want to see a total memory ( including the swap), use the -t switch, which will display a total line as shown below.

ramesh@ramesh-laptop:~$ free -t
             total       used       free     shared    buffers     cached
Mem:       3566408    1592148    1974260          0     204260     912556
-/+ buffers/cache:     475332    3091076
Swap:      4000176          0    4000176
Total:     7566584    1592148    5974436

24. top command examples

top command displays the top processes in the system ( by default sorted by cpu usage ). To sort top output by any column, Press O (upper-case O) , which will display all the possible columns that you can sort by as shown below.

Current Sort Field:  P  for window 1:Def
Select sort field via field letter, type any other key to return

  a: PID        = Process Id              v: nDRT       = Dirty Pages count
  d: UID        = User Id                 y: WCHAN      = Sleeping in Function
  e: USER       = User Name               z: Flags      = Task Flags
  ........

To displays only the processes that belong to a particular user use -u option. The following will show only the top processes that belongs to oracle user.

$ top -u oracle

25. df command examples

Displays the file system disk space usage. By default df -k displays output in bytes.

$ df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1             29530400   3233104  24797232  12% /
/dev/sda2            120367992  50171596  64082060  44% /home

df -h displays output in human readable form. i.e size will be displayed in GB’s.

ramesh@ramesh-laptop:~$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              29G  3.1G   24G  12% /
/dev/sda2             115G   48G   62G  44% /home

Use -T option to display what type of file system.

ramesh@ramesh-laptop:~$ df -T
Filesystem    Type   1K-blocks      Used Available Use% Mounted on
/dev/sda1     ext4    29530400   3233120  24797216  12% /
/dev/sda2     ext4   120367992  50171596  64082060  44% /home

26. kill command examples

Use kill command to terminate a process. First get the process id using ps -ef command, then use kill -9 to kill the running Gnu/Linux process as shown below. You can also use killall, pkill, xkill to terminate a unix process.

$ ps -ef | grep vim
ramesh    7243  7222  9 22:43 pts/2    00:00:00 vim

$ kill -9 7243

27. rm command examples

Get confirmation before removing the file.

$ rm -i filename.txt

It is very useful while giving shell metacharacters in the file name argument.

Print the filename and get confirmation before removing the file.

$ rm -i file*

Following example recursively removes all files and directories under the example directory. This also removes the example directory itself.

$ rm -r example

28. cp command examples

Copy file1 to file2 preserving the mode, ownership and timestamp.

$ cp -p file1 file2

Copy file1 to file2. if file2 exists prompt for confirmation before overwritting it.

$ cp -i file1 file2

29. mv command examples

Rename file1 to file2. if file2 exists prompt for confirmation before overwritting it.

$ mv -i file1 file2

Note: mv -f is just the opposite, which will overwrite file2 without prompting.

mv -v will print what is happening during file rename, which is useful while specifying shell metacharacters in the file name argument.

$ mv -v file1 file2

30. cat command examples

You can view multiple files at the same time. Following example prints the content of file1 followed by file2 to stdout.

$ cat file1 file2

While displaying the file, following cat -n command will prepend the line number to each line of the output.

$ cat -n /etc/logrotate.conf
    1 /var/log/btmp {
    2     missingok
    3     monthly
    4     create 0660 root utmp
    5     rotate 1
    6 }

31. mount command examples

To mount a file system, you should first create a directory and mount it as shown below.

# mkdir /u01

# mount /dev/sdb1 /u01

You can also add this to the fstab for automatic mounting. i.e Anytime system is restarted, the filesystem will be mounted.

/dev/sdb1 /u01 ext2 defaults 0 2

32. chmod command examples

chmod command is used to change the permissions for a file or directory.

Give full access to user and group (i.e read, write and execute ) on a specific file.

$ chmod ug+rwx file.txt

Revoke all access for the group (i.e read, write and execute ) on a specific file.

$ chmod g-rwx file.txt

Apply the file permissions recursively to all the files in the sub-directories.

$ chmod -R ug+rwx file.txt

33. chown command examples

chown command is used to change the owner and group of a file. \

To change owner to oracle and group to db on a file. i.e Change both owner and group at the same time.

$ chown oracle:dba dbora.sh

Use -R to change the ownership recursively.

$ chown -R oracle:dba /home/oracle

34. passwd command examples

Change your password from command line using passwd. This will prompt for the old password followed by the new password.

$ passwd

Super user can use passwd command to reset others password. This will not prompt for current password of the user.

# passwd USERNAME

Remove password for a specific user. Root user can disable password for a specific user. Once the password is disabled, the user can login without entering the password.

# passwd -d USERNAME

35. mkdir command examples

Following example creates a directory called temp under your home directory.

$ mkdir ~/temp

Create nested directories using one mkdir command. If any of these directories exist already, it will not display any error. If any of these directories doesn’t exist, it will create them.

$ mkdir -p dir1/dir2/dir3/dir4/

36. ifconfig command examples

Use ifconfig command to view or configure a network interface on the Gnu/Linux system.

View all the interfaces along with status.

$ ifconfig -a

Start or stop a specific interface using up and down command as shown below.

$ ifconfig eth0 up

$ ifconfig eth0 down

37. uname command examples

Uname command displays important information about the system such as — Kernel name, Host name, Kernel release number,
Processor type, etc.,

Sample uname output from a Ubuntu laptop is shown below.

$ uname -a
Linux john-laptop 2.6.32-24-generic #41-Ubuntu SMP Thu Aug 19 01:12:52 UTC 2010 i686 GNU/Linux

38. whereis command examples

When you want to find out where a specific Unix command exists (for example, where does ls command exists?), you can execute the following command.

$ whereis ls
ls: /bin/ls /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

When you want to search an executable from a path other than the whereis default path, you can use -B option and give path as argument to it. This searches for the executable lsmk in the /tmp directory, and displays it, if it is available.

$ whereis -u -B /tmp -f lsmk
lsmk: /tmp/lsmk

39. whatis command examples

Whatis command displays a single line description about a command.

$ whatis ls
ls  (1)  - list directory contents

$ whatis ifconfig
ifconfig (8)         - configure a network interface

40. locate command examples

Using locate command you can quickly search for the location of a specific file (or group of files). Locate command uses the database created by updatedb.

The example below shows all files in the system that contains the word crontab in it.

$ locate crontab
/etc/anacrontab
/etc/crontab
/usr/bin/crontab
/usr/share/doc/cron/examples/crontab2english.pl.gz
/usr/share/man/man1/crontab.1.gz
/usr/share/man/man5/anacrontab.5.gz
/usr/share/man/man5/crontab.5.gz
/usr/share/vim/vim72/syntax/crontab.vim

41. man command examples

Display the man page of a specific command.

$ man crontab

When a man page for a command is located under more than one section, you can view the man page for that command from a specific section as shown below.

$ man SECTION-NUMBER commandname

Following 8 sections are available in the man page.

1. General commands
2. System calls
3. C library functions
4. Special files (usually devices, those found in /dev) and drivers
5. File formats and conventions
6. Games and screensavers
7. Miscellaneous
8. System administration commands and daemons

For example, when you do whatis crontab, you’ll notice that crontab has two man pages (section 1 and section 5). To view section 5 of crontab man page, do the following.

$ whatis crontab
crontab (1)          - maintain crontab files for individual users (V3)
crontab (5)          - tables for driving cron

$ man 5 crontab

42. tail command examples

Print the last 10 lines of a file by default.

$ tail filename.txt

Print N number of lines from the file named filename.txt

$ tail -n N filename.txt

View the content of the file in real time using tail -f. This is useful to view the log files, that keeps growing. The command can be terminated using CTRL-C.

$ tail -f log-file

43. less command examples

less is very efficient while viewing huge log files, as it doesn’t need to load the full file while opening.

$ less huge-log-file.log

One you open a file using less command, following two keys are very helpful.

CTRL+F – forward one window
CTRL+B – backward one window

44. su command examples

Switch to a different user account using su command. Super user can switch to any other user without entering their password.

$ su - USERNAME

Execute a single command from a different account name. In the following example, john can execute the ls command as raj username. Once the command is executed, it will come back to john’s account.

[john@dev-server]$ su - raj -c 'ls'

[john@dev-server]$

Login to a specified user account, and execute the specified shell instead of the default shell.

$ su -s 'SHELLNAME' USERNAME

45. mysql command examples

mysql is probably the most widely used open source database on Gnu/Linux. Even if you don’t run a mysql database on your server, you might end-up using the mysql command ( client ) to connect to a mysql database running on the remote server.

To connect to a remote mysql database. This will prompt for a password.

$ mysql -u root -p -h 192.168.1.2

To connect to a local mysql database.

$ mysql -u root -p

If you want to specify the mysql root password in the command line itself, enter it immediately after -p (without any space).

46. yum command examples

To install apache using yum.

$ yum install httpd

To upgrade apache using yum.

$ yum update httpd

To uninstall/remove apache using yum.

$ yum remove httpd

47. rpm command examples

To install apache using rpm.

# rpm -ivh httpd-2.2.3-22.0.1.el5.i386.rpm

To upgrade apache using rpm.

# rpm -uvh httpd-2.2.3-22.0.1.el5.i386.rpm

To uninstall/remove apache using rpm.

# rpm -ev httpd

48. ping command examples

Ping a remote host by sending only 5 packets.

$ ping -c 5 gmail.com

49. date command examples

Set the system date:

# date -s "01/31/2010 23:59:53"

Once you’ve changed the system date, you should syncronize the hardware clock with the system date as shown below.

# hwclock –systohc

# hwclock --systohc –utc

50. wget command examples

The quick and effective method to download software, music, video from internet is using wget command.

$ wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.1.tar.gz

Download and store it with a different name.

$ wget -O taglist.zip http://www.vim.org/scripts/download_script.php?src_id=7701

Did I miss any frequently used Gnu/Linux commands? Leave a comment and let me know.