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File handling demonstration
Input and Output in Ruby example from a Well House Consultants training course
More on Input and Output in Ruby [link]
Source code: filestuff.rb Module: R106

# Open files for read, overwrite and append

fhi = File.new "canal_ip.txt"
filtered = File.new "selected.txt","w"
logged = File.new "logged.txt","a"
counter = 0

# Process a file of data line by line

fhi.readlines.each do |host|
        counter += 1
        # all lines reported to the runner
        STDOUT.write host
        if counter < 10
                # 10 lines written to selected.txt
                filtered.write host
        end
end

# Close files that we have finished reading / writing

fhi.close
filtered.close

# Write and close out logs

# Count of work done logged to control / error channel
STDERR.write "Total of #{counter} lines of data processed\n"
# Collect current date / time object
# and write it to log file in default format
present = Time::now
logged.write "Program run #{present}\n"
logged.close

Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Ruby
 * Ruby Programming
Also available on on site courses for larger groups

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Other Examples
This example comes from our "Input and Output in Ruby" training module. You'll find a description of the topic and some other closely related examples on the "Input and Output in Ruby" module index page.

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