@Rarst: could you give this a spin?

Works with less provided by Git, but fails for Windows native more:

Notice: Undefined offset: 1 in C:\server\www\wp-cli\php\commands\help.php on line
68
Warning: stream_get_contents() expects parameter 1 to be resource, null given in C:\server\www\wp-cli\php\commands\help.php on line 68

That means that more fails for some reason (and that I got the wrong pipe handle).

You should be able to see the error message by piping it explicitly (using the master branch):

wp help core config --color | more -r

No issue with explicitly piping it to more, other than it doesn't have -r argument, but removing it from code doesn't fix issue on pager branch.

Something probably goes bonkers in proc_open() (common story on win) I will see if I can debug it later today.

Looked closer at it. Actually it tries to run less -r and never reaches more because

    if ( 127 == $r ) {
        return false;
    }

doesn't trigger. $r is int(1) in this case, whatever that is supposed to mean...

more works if I change $pagers = array( 'less -r', 'more -r' ); to $pagers = array( 'more' );

127 is the exit code bash sends if a command is not found. It seems to be the same on Windows: http://msdn.microsoft.com/en-us/library/windows/desktop/ms681382%28v=vs.85%29.aspx#ERROR_PROC_NOT_FOUND

Error code meaning might be same, but I am not getting that error code, it's 1 (ERROR_INVALID_FUNCTION according to that list) instead.

Ok, thanks. I guess I'll just have to fire up my old Windows laptop one of these days and figure it out.

It seems detecting if a command is available is not so straigthforward: http://superuser.com/questions/175466/determine-if-command-is-recognized-in-a-batch-file/175831#175831

Also, I found that the list command is a closer equivalent to less: http://malektips.com/xp_dos_0021.html (but it's not available by default)

Decided to skip paging on Windows, since I don't have a Windows machine handy to test either way.

Manual piping should work, though: wp help core config | more.