When I build and run GNU APL on Ubuntu 15.04, ^D seems to behave strangely.
1. The first four times I hit it I get "^D" echoed, followed by a blank line and a helpful message. After that I just get "^D" echoed, with no message at all. (I expected it to exit the interpreter if I hit it n times in a row, for some value of n; this is what the bash shell does when you set e.g. IGNOREEOF=10.) ^D ^D or end-of-input detected (1). Use )OFF to leave APL! ^D ^D or end-of-input detected (2). Use )OFF to leave APL! ^D ^D or end-of-input detected (3). Use )OFF to leave APL! ^D ^D or end-of-input detected (4). Use )OFF to leave APL! ^D ^D ^D 2. The next line I type after hitting ^D always seems to cause a strange error in Command.cc: ^D ^D or end-of-input detected (1). Use )OFF to leave APL! )off EOF at Command.cc:65 )off Goodbye. I had to type )off twice here, because the first one just gave the EOF error and didn't exit the interpreter. Thanks, Jay.