10.1.13 使用管道

check = IO.popen("spell","r+")
check.puts("'T was brillig, and the slithy toves")
check.puts("Did gyre and gimble in the wabe.")
check.close_write
list = check.readlines
list.collect! { |x| x.chomp }
# list is now %w[brillig gimble gyre slithy toves wabe]

File.popen("/usr/games/fortune") do |pipe|
quote = pipe.gets
puts quote
# On a clean disk, you can seek forever. - Thomas Steel
end

IO.popen("-") do |mypipe|
if mypipe
puts "I'm the parent: pid = #{Process.pid}"
listen = mypipe.gets
puts listen
else
puts "I'm the child: pid = #{Process.pid}"
end
end
# Prints:
#   I'm the parent: pid = 10580
#   I'm the child: pid = 10582

pipe = IO.pipe
reader = pipe[0]
writer = pipe[1]
str = nil
thread1 = Thread.new(reader,writer) do |reader,writer|
# writer.close_write
str = reader.gets
reader.close
end
thread2 = Thread.new(reader,writer) do |reader,writer|
# reader.close_read
writer.puts("What hath God wrought?")
writer.close
end
thread1.join
thread2.join
puts str         # What hath God wrought?