pkg-config --version always gives 0.26

Question

So, was reading about pkg-config (I think it's included by default on Debian, which I'm on). But every time I try to find the version for something, it gives me 0.26.

santeyio@Amadeus:/$ pkg-config --version python
0.26
santeyio@Amadeus:/$ pkg-config --version libre-office
0.26
santeyio@Amadeus:/$ pkg-config --version alsdkfj
0.26
santeyio@Amadeus:/$ pkg-config --version firefox
0.26
santeyio@Amadeus:/$ 

So, I tried sudo apt-get removing it, then installing it again. But I get the same results. I know I'm missing something stupid here... can anyone point me in the right direction?

Here's the output from my re-installing, if that's helpful...

santeyio@Amadeus:/$ sudo apt-get install pkg-config
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
calligra-l10n-engb cdparanoia comerr-dev k3b k3b-data k3b-i18n kdevelop-php-docs-l10n
kdevelop-php-l10n krb5-multidev language-pack-kde-en libasprintf0c2:i386 libcroco3:i386
libgcrypt11-dev libgnutls-dev libgnutls-openssl27 libgnutlsxx27 libgomp1:i386 libgpg-error-dev
libgssrpc4 libk3b6 libkadm5clnt-mit8 libkadm5srv-mit8 libkcddb4 libkdb5-6 libkrb5-dev libldap2-dev
libp11-kit-dev librtmp-dev libtasn1-3-dev linux-headers-3.5.0-17 postgresql-client-9.2
postgresql-common python-xkit screen-resolution-extra
Use 'apt-get autoremove' to remove them.
The following NEW packages will be installed:
pkg-config
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 41.3 kB of archives.
After this operation, 136 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu/ quantal/main pkg-config amd64 0.26-1ubuntu2 [41.3 kB]
Fetched 41.3 kB in 0s (66.2 kB/s)   
Selecting previously unselected package pkg-config.
(Reading database ... 247983 files and directories currently installed.)
Unpacking pkg-config (from .../pkg-config_0.26-1ubuntu2_amd64.deb) ...
Processing triggers for man-db ...
Setting up pkg-config (0.26-1ubuntu2) ...

Answer 1

Use --modversion.

$ pkg-config --modversion python
2.7

pkg-config is meant to be used when compiling against a library -- if you're trying to check the version of a package, use dpkg -s

$ dpkg -s firefox
Package: firefox
Status: install ok installed
Priority: optional
Section: web
Installed-Size: 48531
Maintainer: Ubuntu Mozilla Team <ubuntu-mozillateam@lists.ubuntu.com>
Architecture: amd64
Version: 17.0.1+build1-0ubuntu0.12.04.1

Or apt-cache policy

$ apt-cache policy firefox
firefox:
  Installed: 17.0.1+build1-0ubuntu0.12.04.1
  Candidate: 20.0+build1-0ubuntu0.12.04.3
...