# Implement "paste" using ruby **URL:** \ **Category:** Ruby\ **Created:** [March 4, 2009, 5:30am UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947 "2009-03-04T05:30:40Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 5:30am UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/1 "2009-03-04T05:30:40Z")
hi, all I have a programming question: in the \*NIX world, there is a small utility named “paste”, that can combine several files together by columns. For example: file “x.dat”'s content is: 1 2 3 … file “y.dat”'s content is: a b c … then “paste x.dat y.dat \> z.dat” will generate z.dat as: 1 a 2 b 3 c … If I want to do it in Ruby, and number of files is a variable, and each file itself can be potentially huge … what would be the most cost efficient way of implementing this? Thanks in advance. Oliver ---
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 10:05am UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/2 "2009-03-04T10:05:01Z")
Oliver wrote: > If I want to do it in Ruby, and number of files is a variable, and > each file itself can be potentially huge … what would be the most > cost efficient way of implementing this? Assuming the number of files to paste together is reasonable (say under 1000), then I’d simply open all the files up front: files = ARGV.map { |fname| File.open(fname) } and then inside a loop use ‘gets’ to pick one line from each, and output those values together. HTH, Brian. ---
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 11:14am UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/3 "2009-03-04T11:14:46Z")
On Mar 3, 2009, at 20:28 , Oliver wrote: > If I want to do it in Ruby, and number of files is a variable, and > each file itself can be potentially huge … what would be the most > cost efficient way of implementing this? The most cost efficient way is by not reinventing the wheel: system “paste”, \*ARGV ---
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 6:35pm UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/4 "2009-03-04T18:35:20Z")
On Tue, Mar 3, 2009 at 11:28 PM, Oliver [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > … > 3 c > … #!/usr/bin/env ruby -wKU files = ARGV.map { |fname| File.open(fname) } while (lines = files.map {|file| file.gets}).any? {|line| line} puts lines.map {|line| line.to\_s.chomp}.join(“\t”) end – Rick DeNatale Blog: [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) Twitter: [http://twitter.com/RickDeNatale](http://twitter.com/RickDeNatale) WWR: [http://www.workingwithrails.com/person/9021-rick-denatale](http://www.workingwithrails.com/person/9021-rick-denatale) LinkedIn: [http://www.linkedin.com/in/rickdenatale](http://www.linkedin.com/in/rickdenatale) ---
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 8:43pm UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/5 "2009-03-04T20:43:04Z")
On Mar 4, 2009, at 08:22 , Yossef M. wrote: > Either way, this answer is not nearly as helpful as you seem to think > it is. I disagree. The OP emphasized the _most_ cost efficient way. In terms of both CPU time _and_ developer time efficiency, my method reigns supreme. I learned this valuable lesson while at Gemstone. They used unix sort for certain types of sorts (esp for large data) because you can’t beat a 20+ year old tool, so why reinvent the wheel? ---
**Author:** ![oliver](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/85f322/32.png) [@oliver](https://www.ruby-forum.com/u/oliver)\ **Post date:** [March 4, 2009, 5:24pm UTC](https://www.ruby-forum.com/t/implement-paste-using-ruby/161947/6 "2009-03-04T17:24:03Z")
On Mar 4, 4:12 am, Ryan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > The most cost efficient way is by not reinventing the wheel: > > system “paste”, \*ARGV To me, the reasoning behind the question seemed to be what to do if the sytem has Ruby installed, but not the ‘paste’ utility. Or maybe it’s simply an exercise in handling memory usage, speed, and overall efficiency. Either way, this answer is not nearly as helpful as you seem to think it is. But that’s just what I think. Maybe Oliver has different ideas.