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From: aks%anywhere@hub.ucsb.edu (Alan Stebbens)
Newsgroups: comp.lang.perl
Subject: Re: Redirection (STDOUT)
Message-ID: <1991Jun12.172127.10044@uvaarpa.Virginia.EDU>
Date: 12 Jun 91 17:21:27 GMT
Sender: mmdf@uvaarpa.Virginia.EDU (Uvaarpa Mail System)
Reply-To: aks%anywhere@hub.ucsb.edu
Organization: The Internet
Lines: 23

| Is there a way to know whether the standard output has been
| redirectedinside a perl script.
| 
| eg : perl.script > perl.script.out 

Just use the "-t" operator; e.g.:

  alias x perl -e \''printf STDERR "%sTTY\n",(-t STDOUT?"":"Not a ");'\'

  x
  TTY

  x > /dev/null
  Not a TTY

  x > /tmp/x
  Not a TTY

  x | cat
  Not a TTY

  x > /dev/console
  TTY