Detection of redirection, possible?

[Shannon Fang]

Hi All,

How can I detect a ruby program's stdio has been redirected? I would like to
do this:

puts "show message to user"
$stdin.gets unless $stdin.redirected?

This way, if the program runs normally, it show message and wait for user
interaction, if it is redirected to a file, then just puts to that file
without wating for user intervention.

Thanks!
Shannon

 

[Eric Hodel]

Hi All,

How can I detect a ruby program's stdio has been redirected? I
would like to do this:

puts "show message to user"
$stdin.gets unless $stdin.redirected?

This way, if the program runs normally, it show message and wait
for user interaction, if it is redirected to a file, then just puts
to that file without wating for user intervention.

I think you want IO#tty?:

$ ruby -e 'p $stdin.tty?'
true
$ ruby -e 'p $stdin.tty?' < /dev/zero
false

 

[nobuyoshi nakada]

Hi,

At Thu, 27 Oct 2005 15:44:54 +0900,
Shannon Fang wrote in [ruby-talk:162881]:

puts "show message to user"

$stdin.gets if $stdin.tty?