De man 1 write
:
You can prevent people (other than the superuser) from writing to you with the mesg(1) command. Some commands, for example nroff(1) and pr(1), may automatically disallow writing, so that the output they produce isn't overwritten
De man 1 mesg
:
mesg [option] [n|y]
Portanto, executar mesg n
deve desativar isso.