Re: reading in a file

Chris Daves wrote:
> hi,
> 
> i want to create a ruby program that uses a "database" of reference
> specifications held in a text file to process a set of other files that
> cite these references, substituting correct citations in the text and
> adding a reference section to the text after the last file has been
> processed. All the output should be sent to the standard output (except
> errors which should go to standard error). To format the references i
> need to use HTML tags. Some useful tags :
> 
> <b>bold</b> <i>italic</i> <u>underline</u> <sup>superscript</sup>
> 
> i cant find out how to read in the file. where should i save the text
> file on the computer? and where will the new file appear?
> 
> thanks

Look at the doc for the File class and the IO class. File inherits from 
IO so all the methods in IO are available in File.

You can save the text file anywhere. When you open the file for reading 
you have to tell Ruby - actually the File.open method - where it is. For 
example if you save the file in "C:\My Documents\references.txt" then 
you have to tell File.open to open "C:\My Documents\references.txt". 
File.open can open any disk file, as long as you tell it which one to open.

"Standard output" is the console by default, so since you're writing the 
new file to standard output, the new file will appear on your console 
unless you redirect standard output to a file, in which case the new 
file will appear where ever you redirected standard output. Redirecting 
is a function of the command processor or shell, not Ruby. Typically you 
redirect standard output by using ">filename" on the command line. For 
example, the following command redirects standard output to a file 
called "myoutput.txt in the current directory:

ruby mypgm.rb >myoutput.txt

Ruby uses special variables to that represent standard output and 
standard error. See the doc on $stdout and $stderr.


-- 
RMagick: http://rmagick.rubyforge.org/