If you wish to change the your default shell you must do it from ECGATE

user@ecgb11:~> changesh
Enter your user id: user

Your current shell is: /bin/bash
Enter new shell [/bin/ksh, /bin/bash]: 

, please let us know via the ECMWF Support Portal and we will implement that change for you.

Once updated, note the change The change may take a few minutes to synchronise, and will only affect new sessions opened after it is comes into effect.