How to make a standard Unix Filter using Ruby?

Question

I found this ruby problem on RubyQuiz, which states besides the problem itself, the following:

"The script should be a standard Unix filter, reading from files specified on the command-line or STDIN and writing to STDOUT. Each line of input will contain one integer (between 1 and 3999) expressed as an Arabic or Roman numeral"

I have no idea how to do a Unix Filter using Ruby.. to read files in this case,

Could somebody please enlighten me on how to accomplish this task in the best way possible.

Thanks as always!

score 3 · Accepted Answer · edited May 23 '17 at 12:19

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The best way to read files from STDIN is using ARGF, as explained in this answer: Best practices with STDIN in Ruby?

You can write to STDOUT using puts or printf.

For more detailed info about IO in Ruby, read the Ruby Doc: http://www.ruby-doc.org/core/classes/IO.html

edited May 23 '17 at 12:19

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answered Sep 29 '11 at 22:04

Sam Grossberg

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I think that's a pretty good link. Too bad I didn't find it previously. – jlstr Sep 29 '11 at 22:37
Note that `puts` will append a line end, `printf` won't. – ocodo Dec 22 '12 at 01:13
you also need to read about the pipe and filter pattern http://www.dossier-andreas.net/software_architecture/pipe_and_filter.html – I'm Mo Oct 14 '17 at 02:57

How to make a standard Unix Filter using Ruby?

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