I need to check for the presence of STDIN input in a Ruby script, like the mysql command can. If nothing is being directed to STDIN, then the script should not attempt to read STDIN.
How can this be done in a cross-platform way?
Asked
Active
Viewed 5,703 times
21
the Tin Man
- 158,662
- 42
- 215
- 303
dan
- 43,914
- 47
- 153
- 254
1 Answers
33
This is something that's done in Linux a lot:
#!/usr/bin/env ruby
str = (STDIN.tty?) ? 'not reading from stdin' : $stdin.read
puts str
>> $ ruby test.rb
>> not reading from stdin
>> $ echo "reading from stdin" | ruby test.rb
>> reading from stdin
the Tin Man
- 158,662
- 42
- 215
- 303
-
3Any specific reason for using `STDIN` _and_ `$stdin`? – Danny Kopping Oct 11 '19 at 07:58