create an altenative for the new binary with a high priority
$ alternatives --install/usr/bn/em uemacs/opt/em-legacy/em2 1
list all the alternatives
$ alternatives --list
it gives version of te laternatives that is running in the system
$ update-alternatives --version
we ca mnow the configuration with config
$ update-alternatives --config editor
remove micro alternative in the editor group with remove command
$ update-alternatives --remove editor /usr/bin/micro
remove micro alternative in the editor group with remove command
$ update-alternatives --remove editor /usr/bin/micro
get all alternative commands by using the get selections command
$ update-alternatives --get-selections