The two answers I was expecting to this were what Monica said, and "whatever is your distro's version of pacman -Q pkgname".

I don't have a Debian handy to test, but does dpkg/apt really not have a "show installed package info" switch like pacman? I was surprised that you had to pipe 4 steps together to print what version is installed.

Yes, but normally you don't know the name of the package. You usually know the name of the binary. That's why I started with which 'binary'. In this example, the package of neomutt is also called neomutt. But see this other example, with mbsync(1), which is packaged in isync:

alx@debian:~$ which mbsync
/usr/bin/mbsync
alx@debian:~$ which mbsync | xargs dpkg -S
isync: /usr/bin/mbsync
alx@debian:~$ which mbsync | xargs dpkg -S | cut -f1 -d:
isync
alx@debian:~$ which mbsync | xargs dpkg -S | cut -f1 -d: | xargs dpkg -l
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  isync          1.4.4-5+b1   amd64        IMAP and MailDir mailbox synchronizer

You can directly query with the package name: dpkg -l isync, but you'd have to know the name of the package. The pipe is there for getting it from the name of the program.

which mbsync tells you the full path of the binary.

... | xargs dpkg -S (i.e., dpkg -S /usr/bin/mbsync) tells you the package that provides the file

... | cut -f1 -d: extracts the package name alone

... | xargs dpkg -l (i.e., dpkg -l isync) tells you the info about the isync package.

Ah, I see - so figuring out the package name is what makes it complicated. Good point! So this is actually a 3 step process:

• Figure out full path of the command
• Figure out what package owns it
• Figure out the version of the package

Would it be helpful to future readers to replace the example in the answer with this example that makes immediately clear what the extra steps are for?

I think it would be.

I have added a clarification that this is a 3-step process, quoting matthewsnyder‭. Is it good now?

I like the extra explanation steps. I suspect it would be easier for a future reader to match up those steps with the example if the mbsync example was used in the answer instead of the neomutt example (in the same way that it helped me understand in this comment thread).

Hmm, I think so. Can you check now?

Yes I find that much easier to follow.