VIM custom command aliasing/mapping/transformation to existing command

Question

:keep sometext (Custom VIM command) -> :%g!/sometext/d (existing syntax)

How can the above transformation be achieved in VIM?

:keep hello -> %g!/hello/d (as an example)

Answer 1

Give this cmd a try:

 command! -buffer -nargs=1 Keep v/<args>/d 

then you can :Keep pattern

:h command for details.