Posts Categorized: linux

Selectively Checking Disk Usage Excluding Files and Folders

disk usage

Normally to check the disk usage of directories on a linux system I would run:

However, occasionally I want to exclude particular directories that take a long time to check and/or that I am not interested in anyway. The example below run from the root of the filesystem skips checks for /home /local /var… Read more »

Fido U2F Security Key

FIDO U2F Key Opening

So I ordered a FIDO U2F Security Key from a French company ‘Plug-Up’ to have a little play.  It is used in 2-factor authentication so when logging in to a service you first enter your username and password and if correct your are prompted for your second factor (a code sent by SMS or a… Read more »

Linux GPS Logging Data

I took part in a swim this weekend – The Battle of Carlingford Lough. My friend Cormac gave his Panasonic Lumix camera to Mary in the kayak and set the camera to log GPS data. He sent me the GPS log file and I opened the log file with BT747 – a Java application that… Read more »

pam_exec.so Execute Commands on User Login

In addition to the normal pam_mkhomedir.so I wanted to create a directory for each user on an alternative disk. To do so I edited:

added the line below (just above the line: session optional pam_mkhomedir.so)

Then created the create_dir.sh file:

and added the following:

It is also possible to add… Read more »

Disk Space Usage on Linux

CBS.log Disk Usage Analyzer

An example of narrowing down disk space usage issues on Linux. Starting with the following command:

We see that the root volume has 16% space left.

We need to run the du command but I wanted to exclude the nfsmounts of several terabytes to get the answer quicker:

We can see… Read more »

ntopng on CentOS 6

ntopng

Ensure you have the EPEL repository installed first then do the following to add a repository for ntopng:

Add the following (the deri bit at the end below is not cut off – it works):

Install ntopng and dependencies:

Set the services to auto start on boot:

Ensure the GeoIP databases… Read more »

Installing Munin 2.x on Centos 6

Ensure you have the epel repository installed then:

The configuration file for Apache is located at:

Create the username/password file referred to in the above file:

Restart the munin-node service and ensure it starts on boot:

Restart the Apache service to ensure the munin conf is picked up:

Wait for… Read more »

gcp: Copy with a Progress Bar

gcp

I decided to try and use gcp by default in place of the normal cp command so that I would have a progress bar by default. On Ubuntu install gcp with:

Now to use gcp by default instead of cp:

Note: For a recursive copy use a lowercase ‘r’ rather than an uppercase… Read more »

Pxeboot CentOS Environment

Organised Chaos

While re-purposing a few old Google Search Appliances I set up a Network Boot Enviornment as follows: Install Dependencies

Configure tftp

Change tftp Permissions

Copy the Boot Files and DVD Files

Next I copied ISO files for CentOS distributions to the machine and mounted them loopback to retrieve… Read more »