how can i tell blender to change the mesh name automatically to the object name
when i rename the object ?
thank you
any one ? please ? 
yes/no/maybe?
You cannot do that… Blender puts automatic names following the order of object/mesh/lamp/cam/empty/etc. in order of their getting in the scene. It tries to fill the gaps too… So if you have cube with a mesh named “Cube”-“Cube”, the second cube with its mesh will be “Cube.001”-“Cube.001” and the third --> “Cube.002”-“Cube.002”. If you now rename the object second cube to “Cube_2”, its mesh remains “Cube.001” so if you add a new cube, together with its mesh it will form the couple “Cube.001”-“Cube.003”… and this needs re-naming to sinchronise names of the object and its mesh 
Regards,
Press F9 and type anew name in the ME field. While you are there, type a new name in the OB field. If you use the N-Key, the numeric dialog only supports renaming of the OB.
Blender names are only 21 characters long.
thanks @Abidos ,@Atom
this is what i know so far
and i wanted to change the mesh name automatically with out write it twice or copy paste it
i think its good to give the mesh the same name as the object
i had a case when some objects ware missing in my blend file
looking at the “OOps schematics” show only meshes for missing objects
what i had to do is to create a new object (plane \ cube \sphere not matter )
and in F9 panel i needed to select the desired mesh (ME)
since i had lots of meshes i start losing my hands.
since then i decided to name the mesh and the object at the same name
thank you for your answers
A trick to spare you from typing or double-clicking (in case you weren’t aware of this option):
- hover the mouse cursor over the object name (ormesh name)
- hit <CTRL><C> to copy the name
- hover the mouse cursor over the mesh name
- hit <CTRL><V> to paste.
Also works with other fields; speeds up the workflow a bit.
wow nice thank you .
i didnt know that