dexec outputs 'stdin: is not a tty' for all ruby and objective c input

[andystanton]

Any ruby or objective c input to dexec (from stdin or file) prefixes its output with the message:

stdin: is not a tty

For example:

Running this helloworld.rb script:

puts "hello world"

gives the following output:

$ dexec helloworld.rb

stdin: is not a tty
hello world

[andystanton]

Adding this to the ruby dockerfile made the message disappear:

RUN         sed -i '/tty/!s/mesg n/tty -s && mesg n/' /root/.profile

Fix found here: http://foo-o-rama.com/vagrant--stdin-is-not-a-tty--fix.html