From BlenderWiki
Curve Tools panel
This panel is available in edit mode, when the object being edited is of type curve.
Translate is equivalent to 3D View » Curve » Transform » Grab/Move (G).
Rotate is equivalent to 3D View » Curve » Transform » Rotate (R).
Scale is equivalent to 3D View » Curve » Transform » Scale (S).
Tilt is equivalent to 3D View » Curve » Control Points » Tilt (CtrlT).
Shrink/Fatten shrinks or fattens the selected control points, which in practice, changes interactively their radius values.
Duplicate is equivalent to 3D View » Curve » Add Duplicate (⇧ ShiftD).
Delete is equivalent to 3D View » Curve » Delete... (X).
Toggle Cyclic is equivalent to 3D View » Curve » Toggle Cyclic (AltC).
Switch Direction is equivalent to 3D View » Curve » Segments » Switch Direction .
Set Spline Type lets you choose the type of all those curves with any aof their components (control points and/or handles) selected:
- Poly turns the curves into polygonal (flat) curves.
- Bezier turns the curves into bezier curves.
- NURBS turns the curves into NURBS curves.
Regarding the handles buttons, you can quickly turn the selected ones automatic (Auto), vector (Vector), aligned (Align) or free (Free).
Extrude is equivalent to 3D View » Curve » Extrude Curve and Move (E).
Subdivide is equivalent to 3D View » Curve » Segments » Subdivide.
Those buttons under the Repeat and Grease Pencil sections keep the same functionality than those buttons with the same name in the Object Tools panel.
