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rubygrepmultiline

Multiline file grep

I have a file that has sections like this,

flags...id, description, used, color
AB, "Abandoned", 0, 13168840
DM, "Demolished", 0, 15780518
OP, "Operational", 0, 15780518...

where ... represents a series of control characters e.g. ETX and STX. I am trying to grab multiple lines from the file.

I am using the following code:

f = File.open(somePath)
r = f.grep(/flags.+id, description, used, color(?<data>(?:.|\s)*?)[\x00-\x08]/)

This code does not work. I do not understand why. The documentation of grep appears to insinuate that the file is parsed line by line. I have a feeling that this may be the reason why the regular expression isn't returning any results.

  1. Am I correct that grep uses line-by-line parsing? Is this why my regex isn't working as intended?
  2. Would it be better to use file.each_line to capture the data?
  3. Are there better/cleaner alternatives to all of the above?
Solution

  • String#scan comes to the rescue:

    File.read('/path/to/file').scan(
  /flags.+id, description, used, color(?<data>(?:.|\s)*?)[\x00-\x08]/m
)