Print from pi

Printing from a RaspberryPi to a line printer (dot matrix, receipt printer) can be done quite simply, by simply writing the text to printer using:

echo "hello printer" > /dev/usb/lp0

Where:

• /dev/usb/lp0 is the location of the printer
• > is a write to command

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Sara wants to expand this mechanism, to have ePub's hyperlinks to make the printer print the words under the hyperlink.

In order to do so, a possible plan:

• have words in epub under hyperlink pointing towards a server-side script
  • ? how can the hyperlinked word be added to href from the hyperlink. Eg. <a href="http://address.to.server/WORD">WORD</a>
• the server side receives the words and writes it to the Pi

How does server writes to the Pi ?

• set a reverse ssh tunnel that allows the logging in to Pi from remote server. http://www.thegeekstuff.com/2013/11/reverse-ssh-tunnel
  • use ssh keys to avoid password requests.
  • ensure that when Pi boots the ssh tunnel is started, by making it into a service http://blog.scphillips.com/posts/2013/07/getting-a-python-script-to-run-in-the-background-as-a-service-on-boot/
• server runs print command over ssh. eg. ssh user1@server1 'df -H' ssh user1@server1 'echo "hello printer" > /dev/usb/lp0' ssh pi.sara 'echo "my sentence" > /root/foo'

How to to run commands on server from ebook?

• ebook links to cgi script
  • ideally the word wrapped in book would be sent to cgi
  • cgi scripts runs command on server, addressed to Pi