Intermediate Linux / Unix System Administrator Tutorials

These tutorials assumes that you have strong understanding of Unix like operating systems and very comfortable with most aspects of the Unix/Linux operating system. Familiar with fundamental networking/distributed computing environments is required. ( rss feed )

Python Command Line Arguments Examples

by on March 13, 2013 · 3 comments

I am a new Python programming user. I am working on user-friendly command-line interfaces, and I want to pass input via the shell args as follows:

./myscript.py filename
./myscript.py in.file output.file
./myscript.py -i in.file -o output.file

How do I pass and parse command-line options and arguments using Python under Unix like operating systems?

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RHEL / CentOS: SELinux Is Preventing /sbin/iptables-multi-1.4.7 From Read Access On The File/rawip_socket

by on March 10, 2013 · 0 comments

I upgraded my system to RHEL/CentOS v6.4 and I am getting the following error for 3rd party packages such as Shorewall and fail2ban:

Mar 10 03:43:56 b2 setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file . For complete SELinux messages. run sealert -l dea027a2-81dd-4394-96d4-f0d1160c9307
Mar 10 03:43:56 b2 setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from create access on the rawip_socket . For complete SELinux messages. run sealert -l 08757ff1-a08d-4c06-a08b-ff5d53712305
Mar 10 03:43:56 b2 setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file . For complete SELinux messages. run sealert -l dea027a2-81dd-4394-96d4-f0d1160c9307
Mar 10 03:43:56 b2 setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from create access on the rawip_socket . For complete SELinux messages. run sealert -l 08757ff1-a08d-4c06-a08b-ff5d53712305
Mar 10 03:43:56 b2 setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file . For complete SELinux messages. run sealert -l dea027a2-81dd-4394-96d4-f0d1160c9307

How do I fix this problem?

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CentOS / RHEL v6.x: Install And Configure Serial Console

by on February 25, 2013 · 2 comments

How do I configure serial console under CentOS Linux or Red Hat Enterprise Linux 6.x running on HP or Dell server?

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Linux: Find Out What Process Are Using Swap Space

by on January 15, 2013 · 2 comments

The top and free command display the total amount of free and used physical and swap memory in the server. How do I determine which process is using swap space under Linux operating systems? How do I find out swap space usage of particular process such as memcached?

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Squid Proxy Server Change Outgoing IP Address

by on January 15, 2013 · 1 comment

I have Squid caching proxy server deployed on Rackspace based server in UK. This server has four IP address. I would like to change outgoing IP addresses from default 1.2.3.1 to 1.2.3.4. How do I change proxy server outgoing IP address under Linux or Unix operating systems?

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OpenBSD: Configure Network Interface As A Bridge / Network Switch

by on January 13, 2013 · 3 comments

I have Soekris single board communication embedded computers which is optimized for low power and network usage. The server has four Ethernet ports. How do I setup IPv4 software bridge using OpenBSD operating systems so that the rest of four ports act as a network switch?

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RHEL / Centos 6: Install Nginx Using Yum Command

by on January 7, 2013 · 2 comments

How can I install Nginx web server On CentOS Linux 6 or Red Hat Enterprise Linux 6 using yum command?

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