"python -m inspect <name>" doesn't currently do anything.
It would be handy if this:
    python -m inspect site
Was roughly equivalent to:
    python -c "import inspect, site; print(inspect.getsource(site))"
Even better would be if it understood entry point notation so you could use "modname:qualname" to get the source code of a particular item within a module.

At the risk of unnecessary complication, there is also other information that could be output, depending on the referenced object (module vs. class/func via qualname).  For instance, a module's __file__ would be handy.  So, the output could have a "header" with the relevant info, followed by a blank line, and then the source code.
I suppose something like that could be added later with a commandline option, like "python -m inspect --info site", rather than being default behavior.  Then this issue can stay focused on the simpler idea. :)
Regardless, your proposal sounds good to me.  I don't see any other meaningful use for "-m inspect".

I agree that it will be better to output a formalized report about a module and it's contents using inspect.getmoduleinfo() and inspect.getmembers().

I realised that with the "module:qualname" syntax, it's straightforward to expand this beyond module introspection to arbitrary objects.
What I suggest we could output:
- a header with key module info (names taken from PEP 451):
    Origin
    Cached
    Submodule search path
    Loader (repr output)
- for non-module objects, also include the line within the file (if it can be determined)
- the output of getsource() if a "--source" option is given

Hello, here's a basic patch. Currently, the header info is printed by default, while the source can be retrieved by using --source (although I would prefer them to be switched, the source should be shown by default and the header info only when requested). It understands the entry point notation, like 'unittest:util.safe_repr'.

New changeset 2e1335245f8f by Nick Coghlan in branch 'default':
Close #18626: add a basic CLI for the inspect module
http://hg.python.org/cpython/rev/2e1335245f8f

Thanks for the initial patch Claudiu - I tweaked it a bit before committing it.
* as you suggested, displaying the source is the default, with a --details option to display the formatted info instead
* changed the displayed details (e.g. only displaying the search path for packages, displaying the line number for classes and functions
* a few tweaks to the actual implementation (e.g. using partition over find, avoiding tracebacks for a couple of likely user errors)

nosy: + python-dev
messages: + msg198272

resolution: fixed
stage: needs patch -> resolved

nosy: + Claudiu.Popa
messages: + msg197919

keywords: + patch