Category Archives: Linux

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 -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)

Setting Static IP in Linux

To setup a static IP in ubuntu, edit your networking settings file.

Here is an example of how to do it:

Open /etc/network/interfaces:

Use these configurations:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static

DHCP Address Configuration:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

Then restart the service: /etc/init.d/networking restart (Make sure you are running with admin privileges when restarting 🙂 )

Generating a SSL Cert with Apache & openSSL

Registering a SSL cert is always kind of a mystery for me. You always have to use a crazy long command line command and the wizard always asks funky questions. Hopefully this tutorial will help clarify the process.

First run the following command:

openssl req -new -newkey rsa:2048 -nodes -keyout yourdomain.key -out yourdomain.csr

And what the command does is it is generating a 256bit SSL certificate. RSA:1024 would generate a 128bit certificate. When the process has finished, you will have yourdomain.key and yourdomain.csr. yourdomain.key should NOT be distributed. This is your key to decrypt your traffic. The CSR should be presented to your CA (certificate authority).

As far as the generation process goes, you will be presented with a few questions:
Country: The two-letter International Organization for Standardization (ISO) format country code for where your organization is legally registered. This would be US for the United States.
State or Province: Name of the state or province where your organization is located. Write out the name in full.
City or Locality: Name of the city where your organization is registered/located. Write out the name in full.
Organization Unit: This may be left blank. However, if you are a company, you may want to put your company nickname here. I.e. Vooba instead of Vooba LLC
Organization: Vooba LLC
Passphrase: Depending on your registrar, you can/can’t use this. If you can’t use it, I recommend finding a different company. Use a strong password here.
Common Name: The fully-qualified domain name (FQDN), or URL, you want to secure. If you are not using a wild-card domain (*, use This will allow and to be secured. If you only secure, will be invalid.

Hope this helps and clarifies the process!

Errors From Package Manager in Ubuntu 11.10

Getting the following message from Package Manager in Ubuntu 11.10?

Requires installation of untrusted packages
The action would require the installation of packages from not authenticated sources.

And when you click on the Details dropdown it shows all of the packages that need to downloaded?

Run the following commands:

cd /var/lib/apt
sudo mv lists lists.old
sudo mkdir -p lists/partial
sudo apt-get update

These commands will save a backup of the old lists and then create a new lists folder.

More information can be found here.