I noticed this problem when I became confused with pipe, one command send its executing output to the STDOUT, which is the STDIN for the other command, which can read from STDIN.

How do I know if a Linux command can read from STDIN?

Is there a feature to distinguish commands that can read from STDIN from those cannot?

  • 6
    I think this is a per-application thing. The best way to know is really just to read the man page or test it yourself.
    – n0pe
    Dec 15, 2011 at 0:37
  • This would require solving the halting problem Dec 21, 2011 at 1:03

1 Answer 1


(In response to the upvotes on my comment)

There isn't a concrete way of determining if an application reads from STDIN or something else. In general, you'll have to try piping something to it or reading the program's man page.

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