Subject: Re: cat(1) question: multiple "-"s
To: Simon Burge <>
From: Hubert Feyrer <>
List: netbsd-users
Date: 04/19/2006 09:46:28
On Wed, 19 Apr 2006, Simon Burge wrote:
> SUSv3 talks about this a little, saying that it really only makes sense
> for when standard input is a terminal:
>     The command:
> 	cat start - middle - end > file
>     when standard input is a terminal, gets two arbitrary pieces of
>     input from the terminal with a single invocation of cat. Note,
>     however, that if standard input is a regular file, this would be
>     equivalent to the command:
> 	cat start - middle /dev/null end > file
>     because the entire contents of the file would be consumed by cat
>     the first time '-' was used as a file operand and an end-of-file
>     condition would be detected immediately when '-' was referenced the
>     second time.

OK - i guess that's the same for pipes as for files then.

  - Hubert