ruby 'script = $0'

Question

我在查看 Ruby 脚本时遇到了 script = $0。我做了一些谷歌搜索，但我还没有找到关于它的作用的明确答案。我相信它可以防止您读取大于内存的文件，对吗？

谢谢，我在下面有完整的脚本，因此您可以在上下文中查看它:

# Takes the name of a file as an argument and assigns to filename 
filename = ARGV.first 
script = $0

puts "We're going to erase #{filename}."
puts "If you don't want that, hit CTRL-C (^C)."
puts "If you do want that, hit RETURN."

print "? "
STDIN.gets

puts "Opening the file..."
target = File.open(filename, 'w')

puts "Truncating the file. Goodbye!"
target.truncate(target.size)

puts "Now I'm going to ask you for three lines."

print "line 1: "; line1 = STDIN.gets.chomp()
print "line 2: "; line2 = STDIN.gets.chomp()
print "line 3: "; line3 = STDIN.gets.chomp()

puts "I'm going to write these to the file."

target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

puts "And finally, we close it."
target.close()

Answer 1

$0 是 Ruby 的全局变量之一。来自 here :

$0 -- Contains the name of the script being executed. May be assignable.