Operating Systems

Adnan Khurshid on January 31st, 2015

Enthusiastic about python? Well, this language has been gaining popularity. Only 2 commands & you will be set to go. $ yum groupinstall “Development tools” $ yum install zlib–devel bzip2–devel openssl–devel ncurses–devel sqlite–devel readline–devel tk–devel gdbm–devel db4–devel libpcap–devel xz–devel It will take around 3 to 5 minutes & you will be set. Run “Python” to […]

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Adnan Khurshid on December 15th, 2014

Having difficulty in connecting to internet from VMware? Recently I installed CentOS in the VMWARE for configuration purposes. I thought it would be beneficial to share how to connect to internet via Linux installed on VMWARE; it can save your time Please note that network can be configured on Linux from the below files. /etc/sysconfig/network […]

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Adnan Khurshid on June 6th, 2011

touch command is used to modify the timestamps of the file. Suppose, you want to modify the time stamp of the file top.txt, use the command as follows: linux:~ # ls -l top.txt -rw-r–r–  1 root root 9637 Apr  2 00:20 top.txt linux:~ # linux:~ # touch -t 201106062145 top.txt linux:~ # ls -l top.txt […]

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Adnan Khurshid on May 30th, 2011

The background processes in Linux refer to the processes running in the background for a particular session which foreground processes are the ones which are currently being operated upon. The commands to manage the processes are as follows: Show background jobs: Use ‘bg’ command to display all the processes which are running in the background.

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Adnan Khurshid on April 5th, 2011

A crontab contains entries for a cron job. Entries in the crontab are separated by newline characters. Each crontab contains six fields separated by spaces as shown below: Minute Hour Day Month Weekday Command Each field is explained below: Minute: 0 ~ 59 Hour: 0 ~ 23 Day: 1 ~ 31 Month: 1 ~ 12 […]

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Adnan Khurshid on April 4th, 2011

While typing commands on a unix system, removing a miss-typed character by the backspace writes down a character ^H instead. To remove a character, you must use Ctrl+BackSpace instead. However, this exercise is quite frustrating for the users. To get rid of this, use stty erase command as demonstrated below: root@mms1 # ls -l^H^H^H^H ls: […]

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Adnan Khurshid on March 24th, 2011

I had written an article previously on how to set the environment variables in Linux/Unix system. You may want to have a look it here. Let’s see how we can delete the variables in the SUN Solaris system. The “env” command will display all the variables in the current user. SUNOS% env HOME=/opt/oracle PATH=/opt/JDK/j2sdk1.4.1_02/bin:/bin:/usr/bin:/usr/ucb:/usr/ccs/bin:/etc:/usr/local/bin:/opt/usr/local/bin:/usr/dt/bin:/opt/iplanet/servers:/opt/oracle/oracle9/bin:/opt/oracle/jre/1.1.8/bin:/opt/oracle/web/bin:/opt/oracle/mms_run/bin:/opt/oracle/mms_run/shell:. LOGNAME=oracle […]

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Adnan Khurshid on March 22nd, 2011

Normally, if you use the man command to find out the method to add routes to the SUN machine, it will come up with the ‘route add’ command but is that command enough to add the routes securely to the system? Well, let us find it out. Before getting involved, just for the sake of […]

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Adnan Khurshid on February 22nd, 2011

Finding large files: Suppose we are facing a disk space issue in one system user directory and we want to find out which files are using most of the disk space, we can run the following command to find it out: <36 SMSC :/export/home2/mml/tmp> find /export/home2/mml/ -size +400000| sort –r| head –3 /export/home2/mml/sms/bin/core_20110119152929_14771 /export/home2/mml/sms/bin/core_20101231115847_13489 /export/home2/mml/sms/bin/core_20101204105309_5074 […]

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Well, we know that command ‘ps –aux’ will show all the processes currently running on the system. We can sort the output of this command by using sort command piped after ps. We discussed about sort command before, you might want to have a look at it here. Lets first check the output of ps […]

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