Install GNU APL.
cd ~/Downloads wget ftp://ftp.gnu.org/gnu/apl/apl-1.7.tar.gz tar xzf apl-1.7.tar.gz cd apl-1.7 ./configure make sudo make install
Set up the keyboard (for all the weird symbols). On Ubuntu GNOME 17.04, go to:
settings -> region and language -> [+] input source -> English (region) -> APL (dyalog)
Then set a good fixed-width font so the symbols show up correctly. Go here and download the recommended font, open and install it. Then open the GNOME Tweak Tool:
fonts -> monospace -> APL385 Unicode Regular -> SelectAnd you're done. Use
win + space
to switch between the fonts.