# Ruby Command Line One Liner **URL:** \ **Category:** Ruby\ **Created:** [January 1, 2009, 8:52pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715 "2009-01-01T20:52:03Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 1, 2009, 8:52pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/1 "2009-01-01T20:52:03Z")
Hi, I try to write a Ruby one-liner that replaces the header information of some \*.java files. My first try worked perfect for a single file. But I have no idea on how to change my one-liner to work with multiple files. Here is my one-liner for a single file: ruby -i.bak -p -e ‘puts ARGF.read.gsub(/.\*(?=package)/m,"/\*\*\n \* foo.bar 2001-2009\n\ \*\*/\n")’ test/Test.java Does anybody have a idea on how to solve this problem for all \*.java files in the test directory? Thanks for your answer, Alain. ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 1, 2009, 8:58pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/2 "2009-01-01T20:58:47Z")
Hi – On Fri, 2 Jan 2009, Alain H. wrote: > ruby -i.bak -p -e ‘puts ARGF.read.gsub(/.\*(?=package)/m,“/\*\*\n \* foo.bar > 2001-2009\n\ \*\*/\n”)’ test/Test.java > > Does anybody have a idea on how to solve this problem for all \*.java > files in the test directory? The -p flag will do the read/write loop for you, so all you have to do is something like this: $ cat abc.txt hello $ cat def.txt goodbye $ ruby -pi.bak -e ‘$\_.upcase!’ abc.txt def.txt $ cat abc.txt HELLO $ cat def.txt GOODBYE David – David A. Black / Ruby Power and Light, LLC Ruby/Rails consulting & training: [http://www.rubypal.com](http://www.rubypal.com) Coming in 2009: The Well-Grounded Rubyist ([The Well-Grounded Rubyist](http://manning.com/black2)) [http://www.wishsight.com](http://www.wishsight.com) =\> Independent, social wishlist management! ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 1, 2009, 9:35pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/3 "2009-01-01T21:35:47Z")
On Thu, Jan 1, 2009 at 11:51 AM, Alain H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I try to write a Ruby one-liner that replaces the header information of > some \*.java files. > > My first try worked perfect for a single file. But I have no idea on how > to change my one-liner to work with multiple files. You might be interested in this: [http://rush.heroku.com/](http://rush.heroku.com/) ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 4, 2009, 10:29pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/4 "2009-01-04T22:29:44Z")
Hi – On Fri, 2 Jan 2009, Alain H. wrote: > > $ cat abc.txt > > Coming in 2009: The Well-Grounded Rubyist ([The Well-Grounded Rubyist](http://manning.com/black2)) > > /\*\* > > package test; > > … > > If I use the one-liner at the top of the message with an input like > ‘test/Tes\*.java’ then the ARGF stream does somehow not differ between > the different files. It sounds like you might want -n rather than -p. -n does the same loop, but without printing. You could arrange to print once you’ve hit /package/. David – David A. Black / Ruby Power and Light, LLC Ruby/Rails consulting & training: [http://www.rubypal.com](http://www.rubypal.com) Coming in 2009: The Well-Grounded Rubyist ([The Well-Grounded Rubyist](http://manning.com/black2)) [http://www.wishsight.com](http://www.wishsight.com) =\> Independent, social wishlist management! ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 2, 2009, 11:03am UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/5 "2009-01-02T11:03:26Z")
David A. Black wrote: > Hi – > > On Fri, 2 Jan 2009, Alain H. wrote: > > > ruby -i.bak -p -e ‘puts ARGF.read.gsub(/.\*(?=package)/m,“/\*\*\n \* foo.bar > > 2001-2009\n\ \*\*/\n”)’ test/Test.java > > > > Does anybody have a idea on how to solve this problem for all \*.java > > files in the test directory? > > The -p flag will do the read/write loop for you, so all you have to do > is something like this: > > $ cat abc.txt > hello > $ cat def.txt > goodbye > > $ ruby -pi.bak -e ‘$\_.upcase!’ abc.txt def.txt > > $ cat abc.txt > HELLO > $ cat def.txt > GOODBYE > > David > > – > David A. Black / Ruby Power and Light, LLC > Ruby/Rails consulting & training: [http://www.rubypal.com](http://www.rubypal.com) > Coming in 2009: The Well-Grounded Rubyist ([The Well-Grounded Rubyist](http://manning.com/black2)) > > [http://www.wishsight.com](http://www.wishsight.com) =\> Independent, social wishlist management! Thanks a lot for your answer. The problem of the -p flag is, that the input stream is read line by line. Then the regex /.\*(?=package)/ will only be applied to one line. But I want to remove all lines before the line starting with “package”. See the following example: /\*\* - header \*\*/ package test; … The result of the replacement looks like this: /\*\* - foo.bar \*\*/ package test; … If I use the one-liner at the top of the message with an input like ‘test/Tes\*.java’ then the ARGF stream does somehow not differ between the different files. Best regards, Alain. ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 5, 2009, 9:11pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/6 "2009-01-05T21:11:00Z")
On Jan 1, 1:51 pm, Alain H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ruby -i.bak -p -e ‘puts ARGF.read.gsub(/.\*(?=package)/m,“/\*\*\n \* foo.bar > 2001-2009\n\ \*\*/\n”)’ test/Test.java > > Does anybody have a idea on how to solve this problem for all \*.java > files in the test directory? > > ## Thanks for your answer, Alain. > > Posted viahttp://www.ruby-forum.com/. ruby -i.bak -0777 -pe"sub /.\*foo/m,‘bar’" \*.java ---
**Author:** ![helpy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d2c977/32.png) [@helpy](https://www.ruby-forum.com/u/helpy)\ **Post date:** [January 11, 2009, 8:25pm UTC](https://www.ruby-forum.com/t/ruby-command-line-one-liner/156715/7 "2009-01-11T20:25:49Z")
unknown wrote: > On Jan 1, 1:51�pm, Alain H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > ruby -i.bak -p -e ‘puts ARGF.read.gsub(/.\*(?=package)/m,“/\*\*\n \* foo.bar > > 2001-2009\n\ \*\*/\n”)’ test/Test.java > > > > Does anybody have a idea on how to solve this problem for all \*.java > > files in the test directory? > > > > ## Thanks for your answer, Alain. > > > > Posted viahttp://www.ruby-forum.com/. > > ruby -i.bak -0777 -pe"sub /.\*foo/m,‘bar’" \*.java Thanks a lot for the help. The -0777 flag was the key to success, Alain.