[lug] stderr woes

[Ron Wright]

The kernel manages /dev/fd/2.  It will be different for each login
session.  Try logging in as two different users and follow the links
to see what I mean.

Ron Wright

On Thu, 24 Feb 2005 11:02:35 -0700 (MST), Stephen Queen
<svq at peakpeak.com> wrote:
> On my Slackware box, the file /dev/stderr is a link
> $ ls -l /dev/stderr
> lrwxrwxrwx    1 root     root            4 Mar 19  2004
> /dev/stderr -> fd/2
> 
> $ ls -l /dev/fd/2
> lrwx------    1 username      users          64 Feb 24 10:39
> /dev/fd/2 -> /dev/pts/3
> 
> $ ls -l /dev/pts/3
> crw--w----    1 username      tty      136,   3 Feb 24 10:40
> /dev/pts/3
> 
> So to have write permissions to /dev/stderr on my box you
> would have to be the user username.
> 
> Stephen Queen
> 
> 
> On Thu, 24 Feb 2005, Ron Wright wrote:
> 
> > ~ $ cat tmp.sh
> > #!/bin/bash
> > echo stderr > /dev/stderr
> > echo stdout > /dev/stdout
> > echo tty > /dev/tty
> > ~ $ ./tmp.sh
> > stderr
> > stdout
> > tty
> > ~ $ sudo -u nobody ./tmp.sh
> > ./tmp.sh: /dev/stderr: Permission denied
> > ./tmp.sh: /dev/stdout: Permission denied
> > tty
> >
> > Ron Wright
> >
> > On Thu, 24 Feb 2005 09:42:34 -0500, Michael Hirsch <mdhirsch at gmail.com> wrote:
> > > On Wed, 23 Feb 2005 22:22:34 -0700, Daniel Webb <lists at danielwebb.us> wrote:
> > > > I'm getting the following output sometimes from a script:
> > > >
> > > > /usr/local/bin/ssh-reverse-tunnel: line 63: /dev/stderr: Permission denied
> > > > /usr/local/bin/ssh-reverse-tunnel: line 63: /dev/stderr: Permission denied
> > > > /usr/local/bin/ssh-reverse-tunnel: line 63: /dev/stderr: Permission denied
> > > > /usr/local/bin/ssh-reverse-tunnel: line 63: /dev/stderr: Permission denied
> > > >
> > > > Line 63 in the script is (from a function):
> > > >
> > > > echo "$THIS: $*" >/dev/stderr
> > > >
> > > > If I try:
> > > >
> > > > echo "test" >/dev/stderr
> > > >
> > > > from the command line as the same user that runs the script, it just
> > > > prints "test" (to stderr, I assume).
> > > >
> > > > Is there some obvious thing I'm overlooking here?
> > >
> > > Strange.  I can't reproduce that with a silly little script.  Can you
> > > create a smal script that reproduces the problem and post it?
> > >
> > > Michael
> > > _______________________________________________
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