How to back up files periodically using rsnapshot and NFS in Ubuntu Linux

rsnapshot is a utility that uses rsync to synchronize files between two directories. rsnapshot makes it easier for system admin to backup crucial system data files regularly with minimal bandwidth and effort.

This guide assumes that you’ve already installed nfs-client and rsnapshot via “apt-get” utility in your Debian/Ubuntu Linux system.

Assumptions:
The backup server is connected in the same LAN as the main computer. The backup server is mounted as NFS on the main computer, ip address of the backup server is 192.168.1.100.

Step 1: Create a script to mount backup server filesystem
This is to ensure that the backup server is available at least hourly (or daily, depending on your requirements), save the file as “mount-backup-server.sh”

File content:

#!/usr/bin/bash
# mount-backup-server.sh
mount 192.168.1.100:/backup-point/  /media/backup/

Step 2: Ensure the mount script is run hourly

sudo cp mount-backup-server.sh /etc/cron.hourly
sudo chmod a+x /etc/cron.hourly/mount-backup-server.sh

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How to set the correct Android *.apk MIME Type for Apache Webserver

Android application uses *.apk file as its installation package. It is a variant of the Java JAR file format (which in turn a Zip 2.0 file). Usually the *.apk file is obtained from Android Marketplace, the official channel for getting Android application. However there are some vendors or carriers that allow *.apk file to be downloaded from 3rd-party websites.

Those who elect to upload the *.apk files on their own webserver can add the official Android APK MIME Type to their Apache Web server config file:

Option 1: edit mime.types (for those who have root access)
1. First edit the mime.types file – sudo nano /etc/apache2/mime.types
2. Then add this at the end of the file – application/vnd.android.package-archive
3. Reload the server configuration – “sudo service apache2 reload”
Option 2: edit .htaccess file (for shared server or user who do not have root access)
1. Edit .htaccess
2. Add this line – AddType application/vnd.android.package-archive

This will register the appropriate MIME type for the *.apk file so that both the server and mobile application can handle.

How to extract Audio from Youtube Flash Video (FLV) in Ubuntu Linux

First you need youtube-dl tool or ‘cclive’ to download the Youtube .FLV file.

Then, download the Youtube stream.
python youtube-dl http://www.youtube.com/watch?v=lee7a55401e

Alternatively, you can use ‘cclive’ to download the youtube stream.
cclive http://www.youtube.com/watch?v=lee7a55401e

After that, use ffmpeg to extract the audio and encode it to MP3
ffmpeg -i lee7a55401e.flv vn -acodec libmp3lame -ab 128000 -ar 44100 lee7a55401e.mp3

Note: You need to install the restricted codecs in order to extract MP3 audio files.

Thanks Mohammad Bahathir Hashim for the tip!