Recovering hex data from a large log-file using Ruby and RegEx

Question

I'm trying to filter/append lines of hex data from a large log-file, using Ruby and RegEx.

The lines of the log-file that I need look like this:

Data: 10 55 61 (+ lots more hex data)

I want to add all of the hex data, for further processing later. The regex /^\sData:(.+)/ should do the trick.

My Ruby-program looks like this:

puts "Start"

fileIn = File.read("inputfile.txt")

fileOut = File.new("outputfile.txt", "w+")
fileOut.puts "Start of regex data\n"    

fileIn.each_line do
    dataLine = fileIn.match(/^\sData:(.+)/).captures    
    fileOut.write dataLine
end

fileOut.puts "\nEOF"
fileOut.close

puts "End"

It works - sort of - but the lines in the output file are all the same, just repeating the result of the first regex match.

What am I doing wrong?

sawa · Accepted Answer · 2013-06-05 09:48:46Z

2

You are iterating over the same entire file. You need to iterate over the line.

fileIn.each_line do |line|
    dataLine = line.match(/^\sData:(.+)/).captures    
    fileOut.write dataLine
end

answered Jun 5, 2013 at 9:48

sawa

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3 Comments

Henrik9k Over a year ago

Good point! But now I get an error: <code> Start sma_data.rb:20:in block in <main>': undefined method captures' for nil:NilClass (NoMethodError) from sma_data.rb:19:in each_line' from sma_data.rb:19:in <main>' </code>

sawa Over a year ago

That means you have a line that does not match that regex. You need to apply captures only then dataLine is not nil.

Henrik9k Over a year ago

I thought this might do: fileIn.each_line do |line| line =~ /^\sData:(.+)/ if($1) fileOut.write $1 end end but I get this error: sma_regex.rb:12:in block in <main>': invalid byte sequence in UTF-8 (ArgumentError) from sma_regex.rb:8:in each_line' from sma_regex.rb:8:in `<main>' PS: Can't seem to get code formatting to work

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