Cleaning of Temporary Install Files in Ubuntu/Debian

Cleaning of Temporary Install Files in Ubuntu/Debian can be done by giving
following commands:

$ sudo apt-get autoclean; sudo apt-get autoremove

Web Access through Proxy Server by Terminal Applications

In many companies/Universities, the web access is granted through Proxy Server (Usually SQUID; hence port 3128).
There are many terminal applications (run on command line interface), which access Internet/Web. For example:
wget (to download file), ftp, lynx/links (to access website), apt/yum (to download and install package). If we are behind
proxy, these applications do not work. The easy solution is to set some shell environment variables, explained below:

For accessing web(lynx/links) using a non-authenticated proxy:
$ export http_proxy="http://proxy.yourcompany.com:3128"

Verify that the setting took place
$ echo $http_proxy
http://proxy.yourcompany.com:3128

For accessing web(lynx/links) using a authenticated proxy:
$ export http_proxy="http://username:password@proxy.yourcompany.com:3128"

If you want the change to be permanent (there each time you open a terminal),
add the export line to .bashrc in your 'home' directory.
$ echo 'export http_proxy="http://proxy.yourcompany.com:3128"'″ >> ~/.bashrc

Secure HTTP (over SSL) access
$ export https_proxy="https://proxy.yourcompany.com:3128"

FTP access
$ export ftp_proxy="ftp://proxy.yourcompany.com:3128"

Offline Package Repository in Debian

If you are not connected to internet, then still you can install packages
from Debian Installer DVDs. (Many thanks to my friend P. A. Venkatesh,
for inspiring me to use Debian).

1. Configuration for /etc/apt/sources.list. Just put these 3 lines in it.

deb file:///mnt/debian/disk1/ etch main contrib

deb file:///mnt/debian/disk2/ etch main contrib

deb file:///mnt/debian/disk3/ etch main contrib


2. Create directories.

# mkdir -p /mnt/debian/disk1
# mkdir /mnt/debian/disk2
# mkdir /mnt/debian/disk3

3. Mount *.iso (ISO images) file to to above directories.

# mount -o loop /debian-40r1-amd64-DVD-1.iso /mnt/debian/disk1
# mount -o loop /debian-40r1-amd64-DVD-2.iso /mnt/debian/disk2
# mount -o loop /debian-40r1-amd64-DVD-3.iso /mnt/debian/disk3

4. Now start synaptic package manager and click reload button. And Viola!
you will be able to see packages. Now you can install any package you want. :)