[SATLUG] apt-get question

Don Wright satlug at wricomp.org
Fri Dec 28 01:21:43 CST 2012

wdubose at texas.net wrote:

>I really can't make heads or tails out of man apt-get.
>I think it really should be 
>       sudo apt-get remove ppa:kamalmostafa/fldigi
>and then
>       sudo apt-get autoclean ppa:kamalmostafa/fldigi or just 
>      sudo apt-get autoclean

Let's back up a bit. As far as I can tell, ppa: commands refer to Ubuntu
Launchpad projects. It seems to be a hack to allow small-d developers
(not Official Ubuntu Maintainers) to make code available using the same
package handling as the release repositories. If you're using mainline
Debian, as I am, they may be less useful.

Whether doing it manually or using ppa commands, the sequence is

1. Build one or more sources.list stanzas with specific repository and
release info. Subdirectory sources.list.d includes .list files which are
merged with the master sources.list during package index updates. You
can consider this as subscribing to an update notification service.
   (nano sources.list or add-apt-repository ppa:user/ppa-name)

2. Fetch and install the cryptographic key for each repository. This is
used to validate the downloaded package files. [This is supposed to be
automatic but if it gets out of sync there are manual recovery steps.]

3. Update the local package index using the repositories in step 1.
   (apt-get update)

4. Use the local package index to install/upgrade/remove packages from
the local machine.
   (apt-get install packagename, apt-get upgrade, apt-get remove
packagename, or just use aptitude, synaptic, or whatever GUI package
manager is present)

5. Enjoy!

From the above it looks like you're getting confused between fldigi the
package and fldigi the ppa-archive. Not your fault - they could have
used another name.

If you're using an Ubuntu-family release (and not some other Debian
derivative) the three lines from 

  sudo add-apt-repository ppa:kamalmostafa/fldigi
  sudo apt-get update
  sudo apt-get install fldigi

will 1) subscribe to the fldigi project archive (ppa) as part of your
local list of software sources,
2) fetch the latest package info from the previously selected software
sources and build your local package index, and
3) install the current version of the software.

From then on, fldigi/flarq will be kept updated along with other
installed software, because it is now part of the list of repositories
that updates the local package index. Kamal at the fldigi project can
then update the code in his Launchpad account, causing Launchpad to
update the ppa, and the update is automatically offered to subscribers.

If you want to cancel your subscription to the updates, then 
   sudo add-apt-repository -r ppa:kamalmostafa/fldigi
will cease checking Launchpad for newer versions. You'll still have the
latest version received, though it may be shown as obsolete or manually
installed in aptitude.

Uninstalling is a separate step, using
   sudo apt-get remove fldigi
which only affects the programs on your system, not the list of
available software.

Hope this helps,  --Don

Migraine: All the fun of a hangover without the bother of 
getting drunk.

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