Re: scriptable way to list packages that are not installed

[davidson <davidson@freevolt.org>]

On Sun, 14 Jan 2018, Vasyl Vavrychuk wrote:

> Hi, John,
>
> On Sun, Jan 14, 2018 at 8:48 AM, john doe <johndoe65534@mail.com> wrote:
> > On 1/14/2018 7:28 AM, john doe wrote:
> >
> > $ dpkg-query -W -f='${db:Status-Abbrev}${binary:Package}\n' awk git gawk
> > cmake 2>&1 | awk '!/^ii/ || !/^un/{print $6}'
> > git
> > gawk
> > cmake
>
> I also tried to parse stderr, but then I realized that relying on the output
>
>   dpkg-query: no packages found matching
>
> is not correct since it might be localized and is not suitable for scripting.

You could just discard the stderr, and take the complement of the hits
from dpkg-query, relative to the supplied arguments:

show-installed () {
    dpkg-query -W -f='${db:Status-Abbrev}${binary:Package}\n' "$@" |
    awk '/^ii/ {print $2}'
}

show-absent () {
    universe=("$@")
    diff <( IFS=$'\n' ; sort <<<"${universe[*]}" ) \
	<( show-installed "${universe[@]}" 2>/dev/null ) |
    sed -n 's/^< //p'
}

$ dpkg-query -l not-a-real-package exim4 mksh xorg bash xterm chromium
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                   Version          Architecture     Description
+++-======================-================-================-=================================================
ii  bash                   4.4-5            amd64            GNU Bourne Again SHell
un  exim4                  <none>           <none>           (no description available)
ii  mksh                   54-2+b4          amd64            MirBSD Korn Shell
ii  xorg                   1:7.7+19         amd64            X.Org X Window System
ii  xterm                  327-2            amd64            X terminal emulator
dpkg-query: no packages found matching not-a-real-package
dpkg-query: no packages found matching chromium

$ show-installed !*
show-installed not-a-real-package exim4 mksh xorg bash xterm chromium
dpkg-query: no packages found matching not-a-real-package
dpkg-query: no packages found matching chromium
bash
mksh
xorg
xterm

$ show-absent !*
show-absent not-a-real-package exim4 mksh xorg bash xterm chromium
chromium
exim4
not-a-real-package

(It is above my pay grade to tell whether "sort" needs its flags
tweaked to sort identically to dpkg on arbitary package names.)