Tag Archives: cli

Set static IP on CentOS 6 via command line

Here is how to configure a static IP on CentOS 6 via command line.

  1. Determine which interface you want to configure–in this example, I will be using eth0
    1. ifconfig -a
    2. Show all linux interfaces
  2. Edit the interface you wish to configure (I’ll use nano as vi requires some knowledge for beginner Linux users)
    1. nano /etc/sysconfig/network-scripts/ifcfg-eth0
    2. nano ifcfg-eth0
  3. Use the following settings and then use Control+O to Save and Control+X to Exit
    1. nano /etc/sysconfig/network-scripts/ifcfg-eth0
    2. DHCPCLASS=
      IPADDR=192.168.1.100
      NETMASK=255.255.255.0
      ONBOOT=yes
      BOOTPROTO=STATIC
    3. static IP CentOS
  4. Next, let’s configure the hostname and default gateway.  We will use nano again to edit the file.
    1. nano /etc/sysconfig/network
    2. Ensure GATEWAY=192.168.1.1 has been set
    3. Static Gateway
  5. Next, let’s configure our DNS servers to resolve domain names (in this case, I will set mine to use Google’s DNS servers)
    1. nano /etc/resolv.conf
    2. nameserver 8.8.8.8
      nameserver 8.8.4.4
    3. static nameservers
  6. Restart the networking service for the changes to take effect
    1. /etc/init.d/network restart
    2. restart interface

Setting up Java Runtime Environment 7 (JRE7) on Ubuntu 12.04 via Command Line

Need Java to run an application on your Linux workstation/server?  Follow the steps below via the terminal to install the latest version of Java.

  1. Head over to http://www.java.com/en/download/manual.jsp to find the latest Linux download from your client machine.
  2. Look at the link for the latest Java release for Linux.  Since we are using Ubuntu we do not need the RPM release.  In this case, I will be downloading Java 1.7.0_25-b15 for Linux x64.
    1. The download url is http://javadl.sun.com/webapps/download/AutoDL?BundleId=78697
  3. Head over to the Linux terminal on the machine you want to install Java on, and execute the following command to download the files from Java’s website
    1. wget http://javadl.sun.com/webapps/download/AutoDL?BundleId=78697
  4. Extract the tarball.  Since wget cannot pull the filename like a modern webrbowser, you will have to reference the weird filename AutoDL?BundleId=78697
    1. tar -xvzf AutoDL?BundleId=78697
  5. Find out what the name of the folder is of the java files you extracted by listing the files in the current directory.  At the time of writing this, the extracted folder I had was jre1.7.0_25, so I will continue to reference that moving forward.
    1. ls
  6. Create a folder in the usr folder for Java to reside.
    1. sudo mkdir /usr/java/
  7. Move the files we extracted Java files to the java folder
    1. sudo mv jre1.7.0_25/ /usr/java/
  8. Execute the following to enable the Java Runtime Environment
    1. sudo update-alternatives –install /usr/bin/java java /usr/java/jre1.7.0_25/bin/java 1
  9. Execute the following command to set the default Java to use
    1. sudo update-alternatives –config java
  10. Execute the following command to verify that the latest version of java is installed
    1. java -version
  11. Remove the tarball we downloaded from Java’s website to free up some space
    1. rm ~/AutoDL?BundleId=78697

Dell PowerConnect 5548 – Enable port mirroring/monitoring via command line

To enable port mirror/monitoring on the Dell PowerConnect 5548 series switches, please follow the following steps:

  1. SSH or Telnet to the switch
  2. Login to the switch
  3. Execute the command: enable
  4. Execute the command: config
  5. Execute the command: interface gigabitethernet 1/0/##
    1. In this case, use the port number of the device that will be getting the traffic to analyze.  This is the interface your “wireshark” machine would be connected to, to do a packet capture.
  6. Execute the command: port monitor gigabitethernet 1/0/##
    1. In this case, use the port number of the device you want to see the network traffic/activity on.  For example, if my device that I wanted to monitor was on gigabit port 1/0/5, I would use that, not the machine that is going to receive the traffic (not your “wireshark” machine).

Once you are done with the forward, you can disable port monitoring/mirror by executing the following command after running through steps 1-5 again: no port monitor gigabitethernet 1/0/##

Last, if you want to see the status of your mirrored/monitored port, you can do so by executing the following command after repeating steps 1-3: show ports monitor

How do I find the Cisco MSE Version Number via command line?

If you are trying to find the version number of your Cisco Mobility Services Engine, SSH into the machine and execute the following command:
/etc/init.d/msed status

You should see something similar to the output below:

[root@MYMSE ~]# /etc/init.d/msed status
STATUS: Starting MSE Platform, Waiting to check the status. MSE Platform is up, getting the status

————-
Server Config
————-

Product name: Cisco Mobility Service Engine
Version: 7.0.220.0
Hw Version: V01
….

Hope this helps!

How to install Python via command line on Linux

At the time of writing this, Python 2.7.3 is the latest build of the 2.7 builds. You can simply replace the wget url with the Python 3.x build you wish to download if you want to use those releases instead.

  1. Download the tarball
    1. wget http://www.python.org/ftp/python/2.7.3/Python-2.7.3.tgz
  2. Extract the contents
    1. tar -xzf Python-2.7.3.tgz
  3. Navigate to the extracted folder
    1. cd Python-2.7.3
  4. Configure/Install Python
    1. ./configure
    2. make
    3. sudo make install

Show hard drive size in Linux via command line

If you have ever wanted to view how big your hard drive/partition sizes are in Linux, but only have access to the command line interface, here is the command to do it:
df
df -H (This will show the partition sizes in MB, GB, TB, etc.)
fdisk -l | grep Disk (This will show the physical disks and their corresponding sizes)