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@vroy /extract.rb
Last active Aug 29, 2015

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A simple utility to extract patterns out of input streams
#!/usr/bin/env ruby
# A simple utility to extract patterns out of input streams
#
# Heavily inspired by:
# http://jstorimer.com/2011/12/12/writing-ruby-scripts-that-respect-pipelines.html
# https://gist.github.com/jstorimer/1465437
#
# Examples:
#
# $ extract PATTERN Gemfile
# $ extract PATTERN Gemfile | more
# $ extract PATTERN Gemfile > output.txt
# $ extract PATTERN Gemfile Gemfile.lock
# $ cat Gemfile* | extract PATTERN
#
# Install:
# $ curl https://gist.githubusercontent.com/exploid/8dae1d39544fad407924/raw/2d0da9234de179c43d5e3020e6b6272f10ed3d80/extract.rb > ~/bin/extract
# $ chmod +x ~/bin/extract
require 'optparse'
$options = { }
OptionParser.new do |opts|
opts.banner = "A simple utility to extract patterns out of input streams"
opts.separator ""
opts.separator "Usage:"
opts.separator " extract PATTERN Gemfile"
opts.separator " extract PATTERN Gemfile | more"
opts.separator " extract PATTERN Gemfile > output.txt"
opts.separator " extract PATTERN Gemfile Gemfile.lock"
opts.separator " cat Gemfile* | extract PATTERN"
opts.separator ""
opts.separator "Specific options:"
opts.on("-i", "--ip", "Match IP addresses") do |ip|
$options[:extract_pattern] = /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/
end
opts.on("-p", "--pattern", String, "PATTERN (Ruby regular expression)") do |pattern|
$options[:extract_pattern] = pattern
end
opts.on("-h", "--help", "help") do |h|
puts opts
exit
end
end.parse!
if $options[:extract_pattern].nil?
$options[:extract_pattern] = ARGV.shift || ""
end
# Keep reading lines of input as long as they're coming.
while input = ARGF.gets
input.each_line do |line|
if $options[:extract_pattern]
matches = line.scan(Regexp.new($options[:extract_pattern]))
if matches.any?
begin
$stdout.puts matches.join(", ")
rescue Errno::EPIPE
exit(74)
end
end
end
end
end
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