Gets bug?

Ruby
1
if ARGV.size > 0 puts "first arg is #{ARGV[0]}" end puts "enter text" ans = gets puts "you said #{ans}"

Run this code, as ./test.rb. Then run it with an command line arg, like
“./test.rb -x”. And you will get an error like this:

“test.rb:3:in `gets’: No such file or directory - -x (Errno::ENOENT)”

The fix I have found, is to change gets to $stdin.gets. I saw some
traffic on the mailing list archives regarding this, but no resolution.

Is this expected behaviour?
ruby -v is: ruby 1.8.3 (2005-09-21) [sparc-solaris2.10]

Thanks,

~S

2

On Jan 4, 2006, at 9:17 AM, Shea M. wrote:

Run this code, as ./test.rb. Then run it with an command line arg,
like “./test.rb -x”. And you will get an error like this:

“test.rb:3:in `gets’: No such file or directory - -x
(Errno::ENOENT)”

The fix I have found, is to change gets to $stdin.gets. I saw some
traffic on the mailing list archives regarding this, but no
resolution.

Is this expected behaviour?

Yes it is. Kernel.gets() reads from files specified as command-line
options or STDIN, if none were given. This makes it easy to write
Unix-style filters.

You can always shift the option out of ARGV before calling gets()
with something like:

if ARGV.first == “-x”
ARGV.shift

…

end

Hope that helps.

James Edward G. II

3

Shea M. wrote:

Run this code, as ./test.rb. Then run it with an command line arg, like
Thanks,

~S

I’ve run into this problem before as well, somebody pointed me to the ri
documentation on Kernel#gets, it says the following.

Returns the next line from the list of files in +ARGV+, or from standard
input if no files are present on the command line. Returns +nil+ at end
of file.

Hope this helps.

4

James Edward G. II wrote:

ARGV.shift

…

end

I’d prefer to use OptionParser.parse! for this - but otherwise totally
agree.

robert