[SOLVED] difference between dpkg -l and dpkg -get-selections

austinium · 08-02-2011, 02:32 AM

Hi,

i usually use

Code:

$dpkg -l

to get the list of packages installed on Debian.

http://www.linuxquestions.org/questi...ckages-894808/
as per the the above thread

Code:

$dpkg --get-selections

does the same.

however on my machine, the number of packages is different for both these commands.

Code:

user@user:~$ dpkg --get-selections|wc -l
1683
user@user:~$ dpkg -l|wc -l
1688

The man page for dpkg states that the -l option:

Code:

-l, --list package-name-pattern...
List packages matching given pattern.

so i guess giving it no pattern to match makes it list out all packages.

the man entry for --get-selections is similar

Code:

--get-selections [package-name-pattern...]
Get  list  of  package selections, and write it to stdout. Without a pattern, non-installed packages (i.e. those which have been previously purged) will not be shown.

so why the difference?

doesk dpkg -l list packages which were previously purged?

TobiSGD · 08-02-2011, 03:15 AM

dpkg -l is a package list to read for humans, there it has an header with explanations that counts 5 lines, here in German:

Code:

Gewünscht=Unbekannt/Installieren/R=Entfernen/P=Vollständig Löschen/Halten
| Status=Nicht/Installiert/Config/U=Entpackt/halb konFiguriert/
         Halb installiert/Trigger erWartet/Trigger anhängig
|/ Fehler?=(kein)/R=Neuinstallation notwendig (Status, Fehler: GROSS=schlecht)
||/ Name                                           Version                                        Beschreibung
+++-==============================================-==============================================-============================================================================================================

dpkg --get-selections is not intended to be human readable (although it is), but to get a bunch of selections that can be used to install the same packages again on a different install with dpkg --set-selections && apt-get dselect-upgrade.

austinium · 08-02-2011, 06:12 AM

thanks