deb-sourceslist-change-debhost

#!/usr/bin/ruby -w

def run_filter(filename)
  if filename == '-'
    yield(STDIN, STDOUT)
  else
    # in-place editing of filename
    File.open(filename) do |input|
      File.unlink(filename)
      File.open(filename, 'w') do |output|
        yield(input, output)
      end
    end
  end
end

prefix,filename = ARGV
unless prefix
  STDERR.puts "#{File.basename(__FILE__)}: quickly change all debian.org package source URLs in an apt.sources file to something else. Particularly useful for switching between snapshot.debian.org releases."
  STDERR.puts "usage: #{File.basename(__FILE__)} <url prefix, e.g. http://snapshot.debian.org/archive/debian/xxxx/> [filename (default: sources.list)|-]"
  exit
end

filename ||= 'sources.list'

run_filter(filename) do |input,output|
  while line=input.gets
    if m = line.match(/^deb.*?\s+(.*?debian\.org.*?\/debian.*?)[\s$]/)
      line[m.begin(1)...m.end(1)] = prefix
    end
    output.puts line
  end
end