Running a script on heroku and piping input and output

gistfile1.txt

Don't expect pretty, it's a hack...
We need and END marker on the input because we have to tell the script to exit

$ cat > input.txt
a quick brown
fox jumple over the
laszy dog
END

$ heroku run "perl -pe 'exit if /^END$/; s/(\w)/\1\1/g;'" < input.txt > output.txt

$ cat output.txt 
Running `perl -pe 'exit if /^END$/; s/(\w)/\1\1/g;'` attached to terminal... up, run.2
a quick brown
fox jumple over the
laszy dog
END
aa qquuiicckk bbrroowwnn
ffooxx jjuummppllee oovveerr tthhee
llaasszzyy ddoogg