How to use jigdo downloader to download Debian Linux installation ISO images

Using jigdo downloader is a smarter and greener way of downloading data from the Internet mirrors. In comparison to a regular download where you point your browser or wget command to a single mirror URL, jigdo allows for multiple mirrors where the main feature is to re-use a previously download ISO image of a lower version to use as base and thus only new packages not downloaded previously are downloaded.

For this reason using jigdo is often faster way of downloading debian ISO images. To start using you first need to install it on your system:

# apt-get install jigdo-file

Once the jigdo-file package is downloaded your can start using jigdo do download official Debian instillation images. All you need is the URL of the *.jigdo file of the image you intend to download. In the example below we download Debian Jessie KDE iso image. First start jigdo:

$ jigdo-lite
Jigsaw Download "lite"
Copyright (C) 2001-2005  |  jigdo@
Richard Atterer          |
Getting mirror information from /etc/apt/sources.list


Jigdo will first ask you for a URL of the jigdo file:

 To resume a half-finished download, enter name of .jigdo file.
To start a new download, enter URL of .jigdo file.
You can also enter several URLs/filenames, separated with spaces,
or enumerate in {}, e.g. `http://server/cd-{1_NONUS,2,3}.jigdo'

Once you enter the jigdo file URL then jigdo will try to guess your location and choose a closest mirror. You will have an option to change default settings settings or you can simply accept them by pressing ENTER:

Downloading .jigdo file
--2015-01-28 18:34:35--
Resolving (,,, ...
Connecting to (||:80...
HTTP request sent, awaiting response... 200 OK
Length: 49449 (48K)
Saving to: `debian-jessie-DI-rc1-amd64-kde-CD-1.jigdo'

100%[=====================>] 49,449      63.6K/s   in 0.8s    

2015-01-28 18:34:37 (63.6 KB/s) - `debian-jessie-DI-rc1-amd64-kde-CD-1.jigdo'
saved [49449/49449]

Images offered by
  1: 'Debian GNU/Linux Jessie-DI-rc1 "Jessie" - Official RC amd64 kde-CD
Binary-1 20150109-01:04 (20150109)' (debian-jessie-DI-rc1-amd64-kde-CD-1.iso)

Further information about `debian-jessie-DI-rc1-amd64-kde-CD-1.iso':
Generated on Fri, 09 Jan 2015 01:07:30 +0000

If you already have a previous version of the CD you are                        
downloading, jigdo can re-use files on the old CD that are also                 
present in the new image, and you do not need to download them                  
again. Mount the old CD ROM and enter the path it is mounted under              
(e.g. `/mnt/cdrom').                                                            
Alternatively, just press enter if you want to start downloading                
the remaining files.                                                            
Files to scan:                                                                                                   
The jigdo file refers to files stored on Debian mirrors. Please                 
choose a Debian mirror as follows: Either enter a complete URL                  
pointing to a mirror (in the form                                               
`'), or enter any regular expression                
for searching through the list of mirrors: Try a two-letter                     
country code such as `de', or a country name like `United                       
States', or a server name like `sunsite'.                                       
Debian mirror []: 

after this jigdo will download template which will be used to construct your final image. After successful download you will see a message:

The fact that you got this far is a strong indication that
was generated correctly. I will perform an additional, final check,
which you can interrupt safely with Ctrl-C if you do not want to wait.

OK: Checksums match, image is good!

and your newly constructed image from multiple parts will sit in your current working directory:

$ ls -lh debian-jessie-DI-rc1-amd64-kde-CD-1.iso
-rw-r--r-- 1 lubos lubos 618M Jan 28 19:46 debian-jessie-DI-rc1-amd64-kde-CD-1.iso

Next time you would like to download a newer version of the same image simply point jigdo to a previously downloaded location and it will reconstruct up to date image while downloading only updated files/packages.