show con_name not working in SQLDevelopper I typed show con_name; in sqlDeveloper but the result is the following error : SP2-0158: unknown SHOW option "con_name" ... Other commands like Show user;  work perfectly. I tried in sqlplus and no problem there.

Any idea of what's happening here ?

ps : I'm using Oracle 12c on Linux
SHOW is a SQL*Plus command, but SQL Developer does support all of the SQL*Plus commands

you run them through the 'script engine' which is done using F5 or the 2nd execution button on the toolbar 

you will need to be on a newer version of SQL Developer as we've vastly increased the amount of SQL*Plus support we offer