Custunizing shelf
 

how i do to add a commend like extrude face to the shelf

Hodl down Shift and ctrl while you select extrude face.

Just some rambling from me...

I used to group things together in order to get the pivot point to coordinate 0.0.0, for easy mirroring...

...but with the falcon project I found out at the end, that I had about 1000+ unused group-nodes in the outliner...

So now, I have made a shelf-button for moving the pivot point to project origin! Nice and easy, now I dont have to press that "boring" insert button on my keyboard (although I could set a new hotkey for this...).

Heres the mel command;

move 0 0 0 .scalePivot .rotatePivot ;

If you do this manually this will appear in the editor
move 0 0 0 xxx.scalepivot xxx.rotatepivot ;

xxx = any relevant object
By deleting the whole reference to the object, this command will function on any object later on, and not just the original object, if you just move this command to the shelf with the shift and ctrl keys.