Maybe a shell script showing the inputs more explicitly would help? echo -e '500 miles\nkm' | gnu-units-executable-name But I'm pretty sure from reading t

Maybe a shell script showing the inputs more explicitly would help? echo -e '500 miles\nkm' | gnu-units-executable-name But I'm pretty sure from reading the post that units prompts you first for 'you have' (units and/or measurement to convert) and then prompts you for 'you want' (units to convert to).