ubuntu

How to Tell Which Version of Ubuntu is Running

Since I have several computers that run Ubuntu with different versions on them, there are times when I need to find out which version of Ubuntu is running. One reason is to make sure that your Ubuntu upgrade did in fact take properly.

ts real easy to find out which version Ubuntu you are running. Just open up a terminal window, and type the following:

cat /etc/issue

You will get something like this:

Ubuntu 14.04.1 LTS \n \l

Which tells me that I am running Ubuntu version 14.04 LTS.

Sometimes this file does get edited for security reasons. If the /etc/issue file does not give you any information as to what version of Ubuntu you are running, you can also check the /etc/lsb-release file. In that case, you will see something like this:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION=”Ubuntu 14.04.1 LTS”

If you are running an Ubuntu Workstation, then just click on the SYSTEM SETTINGS icon then DETAILS and it will tell you which version of Ubuntu you are running.

This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.

vsftpd Refusing To Run With Writable Root Inside Chroot

I recently upgraded one of my Ubuntu servers, and I quickly found out that people who were trying to FTP couldn’t login. They got the following message: 500 OOPS: vsftpd: refusing to run with writable root inside chroot. Here is how to fix it.

This is a result of a security “feature” that has been added in the latest update, and released in the Ubuntu upgrade. The problem is that users’ root directory is writable, which isn’t allowed when using chroot restrictions in the new update.

Fortunately, the good folks at The Fronteer Group have backported vsftp until the full release of ver 3 of vsftp comes out. So here is what you do:

login as root (or sudo..) and do the following:
apt-get install python-software-properties
sudo add-apt-repository ppa:thefrontiergroup/vsftpd
sudo apt-get update
sudo apt-get install vsftpd
nano /etc/vsftpd.conf and add the following
allow_writeable_chroot=YES
sudo service vsftpd restart

Normally we all would just edit the /etc/vsftpd.conf file and be done with it. However, in the version of vsftp, this option dosen’t work. When version 3 of vsftp is included in the normal ubuntu server packaging, then all will be fixed. Until then, this workaround worked for me.

This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.

Stop Cron From Sending Mail on a Linux Server

Recently I noticed that cron was sending mail on my Ubuntu server. I needed to figure out how to stop it from sending mail. There are two ways ..to do this. Here is how:

The first way to stop Cron from sending mail involves setting cron so that it doesn’t send mail for all of your cron jobs. To do this, open up the crontab editor with the cron job command, crontab -e. Then above all the other cron job listings, add the line MAILTO=”” Here is an example of the beginning of my crontab file:

#
MAILTO=””
#
50 12 * * * /etc/RotateRsyncLogs.sh

This will configure cron to not send mail at all. Sometimes however you want cron to send mail, but have a specific job to not send mail. In order to do this, just add this to the end of your cron command:

/dev/nul 2>&1
For example:
30 * * * * /etc/runthis.sh >/dev/nul 2>&1

This will redirect the output of the cron job to /dev/nul

This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.

Convert Audio and Video Formats With FFmpeg

Recently at work we needed to extract audio from a Quicktime movie. In exploring different options, I came across the utility FFmpeg. This is a cross-platform utility that can decode, extract, mux, stream, filter, and convert pretty much any audio and video format to any other format. FFmpeg can be downloaded here: FFmpeg Download

FFmpeg contains over 100 codecs, so it is quite comprehensive in its ability to convert various multimedia files. FFmpeg is developed under GNU/Linux, but has also been compiled for Windows and Mac OS X

In my case, I was extracting the audio from a QuickTime video. So in Ubuntu, I just opened up the terminal program, and entered the following

$ ffmpeg -i infile.mov outfile.wav

This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.