apt is missing build-dep changelog and source commands.

[Aminda Suomalainen]

I like that there is now single command to do what previously needed multiple different commands unless you used aptitude.

I aliased those commands to apt when apt exists and noticed that three commands are missing.

```
# 100 LC_ALL=C apt build-dep
E: Invalid operation build-dep
```

build-dep is important command to me, I use it often. And now that apt has process bar, it would be even nicer to have.

```
# 100 LC_ALL=C apt source
E: Invalid operation source
# 100 LC_ALL=C apt changelog
E: Invalid operation changelog
```

I don't use source and changelog so often, but sometimes I need them too. I know that I can use \aptitude build-dep, but that is missing the process bar. I hope to see these three commands and those that I didn't notice missing, but which are important in future version.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: apt 1.0.1ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CurrentDesktop: LXDE
Date: Sun Apr 20 17:40:40 2014
InstallationDate: Installed on 2014-02-01 (78 days ago)
InstallationMedia: Lubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
SourcePackage: apt
UpgradeStatus: Upgraded to trusty on 2014-04-17 (3 days ago)

[Aminda Suomalainen (mikaela)]

It also seems interesting that "apt moo" was decided to be included while it probably has less use that I can see.

```
# apt-get moo
                 (__)
                 (oo)
           /------\/
          / | ||
         * /\---/\
            ~~ ~~
..."Have you mooed today?"...
```

[Aminda Suomalainen (mikaela)]

It seems that "apt policy" and "apt depends" are also missing. "apt-cache policy" is requested to be included when you report bug at Launchpad, so it should probably work with apt as some people are aliasing these commands to apt.

```
2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
```

To get this message, go to https://bugs.launchpad.net/ubuntu/+filebug/?no-redirect and type anything to the box and select "I need to report a new bug" and it reads under "Ubuntu bug reporting guidelines:".

[Aminda Suomalainen (mikaela)]

This bug probably isn't so important. I just noticed that when you enable colours and progress bar, they also appear to apt-* and aptitude.

[Julian Andres Klode (juliank)]

Was fixed some time ago