# Unable to write to file... (example from "pickaxe book", second edition, p128) **URL:** \ **Category:** ruby-talk\ **Created:** [19 January 2006 10:49 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172 "2006-01-19T10:49:43Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![John\_Maclean](https://avatars.discourse-cdn.com/v4/letter/j/e8c25b/32.png) [@John\_Maclean](https://rubytalk.org/u/John_Maclean)\ **Post date:** [19 January 2006 10:49 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/1 "2006-01-19T10:49:43Z")
Following the example from "pickaxe book", second edition, p128 #!/usr/bin/ruby File.open("testfile", "r") do |file|   while line = file.gets     puts line   end end produces copy.rb:2:in `initialize': No such file or directory - testfile (Errno::ENOENT)         from copy.rb:2 > **···** > > -- > John Maclean > MSc (DIC) > 07739 171 531 ---
**Author:** ![HT\_de\_Beer1](https://avatars.discourse-cdn.com/v4/letter/h/ea666f/32.png) [@HT\_de\_Beer1](https://rubytalk.org/u/HT_de_Beer1)\ **Post date:** [19 January 2006 10:54 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/2 "2006-01-19T10:54:39Z")
The problem is clear. You are trying to read a file which does not exist. So, to solve the `problem', you create a file named testfile, put some text in it, and there you go, > **···** > > On Thursday 19 January 2006 11:49, John Maclean wrote: > > > Following the example from "pickaxe book", second edition, p128 > > > > #!/usr/bin/ruby > > File.open("testfile", "r") do |file| > >   while line = file.gets > >     puts line > >   end > > end > > > > produces > > copy.rb:2:in `initialize': No such file or directory - testfile > > (Errno::ENOENT) from copy.rb:2 > > -- > HT de Beer ---
**Author:** ![Zach\_Dennis1](https://avatars.discourse-cdn.com/v4/letter/z/ea5d25/32.png) [@Zach\_Dennis1](https://rubytalk.org/u/Zach_Dennis1)\ **Post date:** [19 January 2006 10:56 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/3 "2006-01-19T10:56:55Z")
John Maclean wrote: > Following the example from "pickaxe book", second edition, p128 > > #!/usr/bin/ruby File.open("testfile", "r") do |file| >   while line = file.gets >     puts line >   end > end > > produces > copy.rb:2:in `initialize': No such file or directory - testfile (Errno::ENOENT) >         from copy.rb:2 John, you need the file named "testfile" to exist before you can run that code. It can't open a file if it doesn't exist! Zach ---
**Author:** ![John\_Maclean](https://avatars.discourse-cdn.com/v4/letter/j/e8c25b/32.png) [@John\_Maclean](https://rubytalk.org/u/John_Maclean)\ **Post date:** [19 January 2006 11:20 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/4 "2006-01-19T11:20:37Z")
Thanks! The light shines. So how can i -write- to a file using the code below as an example? > **···** > > On Thu, 19 Jan 2006 19:56:55 +0900 zdennis \ wrote: > > > John Maclean wrote: > > \> Following the example from "pickaxe book", second edition, p128 > > \> > > \> #!/usr/bin/ruby > > \> File.open("testfile", "r") do |file| > > \> while line = file.gets > > \> puts line > > \> end > > \> end > > \> > > \> produces > > \> copy.rb:2:in `initialize': No such file or directory - testfile (Errno::ENOENT) > > \> from copy.rb:2 > > \> > > > > John, you need the file named "testfile" to exist before you can run that code. It can't open a file > > if it doesn't exist! > > > > Zach > > -- > John Maclean > MSc (DIC) > 07739 171 531 ---
**Author:** ![Diego\_Algorta\_Casama](https://avatars.discourse-cdn.com/v4/letter/d/53a042/32.png) [@Diego\_Algorta\_Casama](https://rubytalk.org/u/Diego_Algorta_Casama)\ **Post date:** [19 January 2006 11:35 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/5 "2006-01-19T11:35:54Z")
John Maclean escribió: > Thanks! The light shines. So how can i -write- to a file using the code below as an example? Change \>\>\> File.open("testfile", "r") do |file| to \>\>\> File.open("testfile", "w") do |file| Read: [http://www.ruby-doc.org/core/classes/File.html](http://www.ruby-doc.org/core/classes/File.html) [http://www.ruby-doc.org/core/classes/IO.html](http://www.ruby-doc.org/core/classes/IO.html) Diego > **···** > > > On Thu, 19 Jan 2006 19:56:55 +0900 \> zdennis \ wrote: > > > > > John Maclean wrote: > > > > > > > Following the example from "pickaxe book", second edition, p128 > > > > > > > > #!/usr/bin/ruby File.open("testfile", "r") do |file| > > > >   while line = file.gets > > > >     puts line > > > >   end > > > > end > > > > > > > > produces > > > > copy.rb:2:in `initialize': No such file or directory - testfile (Errno::ENOENT) > > > >         from copy.rb:2 > > > > > > John, you need the file named "testfile" to exist before you can run that code. It can't open a file if it doesn't exist! > > > > > > Zach ---
**Author:** ![Jacob\_Fugal](https://avatars.discourse-cdn.com/v4/letter/j/439d5e/32.png) [@Jacob\_Fugal](https://rubytalk.org/u/Jacob_Fugal)\ **Post date:** [19 January 2006 16:10 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/6 "2006-01-19T16:10:02Z")
Well you need more than that. For one thing the file.gets will fail if file was opened in write mode. Also the puts is going to STDOUT, not the file. You probably want something like this: #!/usr/bin/ruby File.open("testfile", "w") do |file|   while line = gets     file.puts line   end end This will get input from STDIN and write it out to test file. Program terminates on EOF marker (CTRL-D when run interactively). Jacob Fugal > **···** > > On 1/19/06, Diego Algorta Casamayou \ wrote: > > > Change > > \>\>\> File.open("testfile", "r") do |file| > > to > > \>\>\> File.open("testfile", "w") do |file| ---
**Author:** ![Mike\_Fletcher](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@Mike\_Fletcher](https://rubytalk.org/u/Mike_Fletcher)\ **Post date:** [19 January 2006 16:29 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/7 "2006-01-19T16:29:13Z")
John Maclean wrote: > Thanks! The light shines. So how can i -write- to a file using the code > below as an example? Open a file for writing File.open( "infile", "r" ) | in |   File.open( "outfile", "w" ) | out |     while line = in.gets       out.print line     end   end end See the docs for IO which explain all the mode flags ("r", "w", "a", etc.). > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Diego\_Algorta\_Casama](https://avatars.discourse-cdn.com/v4/letter/d/53a042/32.png) [@Diego\_Algorta\_Casama](https://rubytalk.org/u/Diego_Algorta_Casama)\ **Post date:** [19 January 2006 16:38 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/8 "2006-01-19T16:38:10Z")
Jacob Fugal escribió: > **···** > > > On 1/19/06, Diego Algorta Casamayou \ wrote: > > > > > Change > > > \>\>\> File.open("testfile", "r") do |file| > > > to > > > \>\>\> File.open("testfile", "w") do |file| > > > > Well you need more than that. For one thing the file.gets will fail if > > file was opened in write mode. Also the puts is going to STDOUT, not > > the file. You probably want something like this: > > > > #!/usr/bin/ruby > > File.open("testfile", "w") do |file| > >   while line = gets > >     file.puts line > >   end > > end > > > > This will get input from STDIN and write it out to test file. Program > > terminates on EOF marker (CTRL-D when run interactively). > > That's right. I focused my reply on on the open method, but missed the full example. > > Diego ---
**Author:** ![Guest2](https://avatars.discourse-cdn.com/v4/letter/g/439d5e/32.png) [@Guest2](https://rubytalk.org/u/Guest2)\ **Post date:** [3 November 2006 17:24 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/9 "2006-11-03T17:24:16Z")
Mike Fletcher wrote: > John Maclean wrote: > > > Thanks! The light shines. So how can i -write- to a file using the code > > below as an example? > > Open a file for writing > > File.open( "infile", "r" ) | in | >   File.open( "outfile", "w" ) | out | >     while line = in.gets >       out.print line >     end >   end > end > > See the docs for IO which explain all the mode flags ("r", "w", "a", > etc.). Do you think this script work? Li > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Marcel\_Ward](https://avatars.discourse-cdn.com/v4/letter/m/a5b964/32.png) [@Marcel\_Ward](https://rubytalk.org/u/Marcel_Ward)\ **Post date:** [3 November 2006 18:08 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/10 "2006-11-03T18:08:21Z")
It fails because "in" is a reserved word in Ruby and cannot be used as a variable name. Try changing the two instances of "in" to "inp" and it will work. > **···** > > On 03/11/06, Li Chen \ wrote: > > > Mike Fletcher wrote: > > \> John Maclean wrote: > > \> [snip] > > \> > > \> File.open( "infile", "r" ) | in | > > \> File.open( "outfile", "w" ) | out | > > \> while line = in.gets > > \> out.print line > > \> end > > \> end > > \> end > > > > Do you think this script work? > > -- > Marcel ---
**Author:** ![Mike\_Fletcher](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@Mike\_Fletcher](https://rubytalk.org/u/Mike_Fletcher)\ **Post date:** [3 November 2006 19:34 UTC](https://rubytalk.org/t/unable-to-write-to-file-example-from-pickaxe-book-second-edition-p128/24172/11 "2006-11-03T19:34:06Z")
Li Chen wrote: > Mike Fletcher wrote: > > > John Maclean wrote: > > > > > Thanks! The light shines. So how can i -write- to a file using the code > > > below as an example? > > > > Open a file for writing > > > > File.open( "infile", "r" ) | in | > >   File.open( "outfile", "w" ) | out | > >     while line = in.gets > >       out.print line > >     end > >   end > > end > > > > See the docs for IO which explain all the mode flags ("r", "w", "a", > > etc.). > > Do you think this script work? As is no (I blame lack of caffeine and/or sleep); but with "do" inserted in the right two places and the reserved word "in" replaced with something that's not a reserved word ( say "inf" ) it works just fine. One should take all example code posted in haste to mailing lists with a grain of salt. > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).