17

I am kind of a newbie to Ruby, I am working out some katas and I stuck on this silly problem. I need to copy the content of 1 file to a new file in 1 line of code

First try:

File.open(out, 'w').write(File.open(in).read)

Nice, but it's wrong I need to close the files:

File.open(out, 'w') { |outf| outf.write(File.open(in).read) }

And then of course close the read:

File.open(out, 'w') { |outf| File.open(in) { |inf| outf.write(outf.read)) } }

This is what I come up with, but it does not look like 1 line of code to me :(

Ideas?

Regards,

Andrew Grimm
  • 78,473
  • 57
  • 200
  • 338
Calin
  • 6,661
  • 7
  • 49
  • 80

4 Answers4

32

Ruby 1.9.3 and later has a

File.write(name, string, [offset], open_args)

command that allows you to write a file directly. name is the name of the file, string is what you want to write, and the other arguments are above my head.

Some links for it: https://github.com/ruby/ruby/blob/ruby_1_9_3/NEWS , http://bugs.ruby-lang.org/issues/1081 (scroll to the bottom).

Andrew Grimm
  • 78,473
  • 57
  • 200
  • 338
19

There are many ways. You could simply invoke the command line for example:

`cp path1 path2`

But I guess you're looking for something like:

File.open('foo.txt', 'w') { |f| f.write(File.read('bar.txt')) }
Oscar Del Ben
  • 4,485
  • 1
  • 27
  • 41
  • yes, this was my second option, but how about File.read('bar.txt'), doesn't it need to close ? – Calin Sep 18 '11 at 20:36
  • you mean like this http://stackoverflow.com/questions/4795447/rubys-file-open-and-the-need-for-f-close – Calin Sep 18 '11 at 20:57
2

You can try:

IO.binwrite('to-filename', IO.binread('from-filename'))

Check the ruby docs:

IO::binwrite & IO::binread

Gabriel Teles
  • 63
  • 5
2

You can do the following:

File.open(out_file, "w") {|f| f.write IO.read(in_file)}
Chandra Patni
  • 17,347
  • 10
  • 55
  • 65