From plank@cs.utk.edu Wed Jun 11 13:54:30 1997
Subject: Re:  Indirection, pipes

>To: plank@cs.utk.edu
>Subject: Indirection, pipes
>
>  This is what I tried from UNIX>
>      cd \bin
>      sh
>      cd
>      cat < f1
>      This is f1.
>      cat f1 f3 > f2
>      cat: f3: No such file or directory
>       cat f1 f3 2> f2
>      f2: File exists.
>       cat f1 f3 2>&1 > f2
>      Ambiguous output redirect.
>       cat f1 f3 > f2 2>&1
>      Ambiguous output redirect.
>        cat f1 f3 >&2 2> f2
>      Ambiguous output redirect.
>        cat f1 f3 2> f2 >&2
>      Ambiguous output redirect.
>       cat f1 f3 2>&1 >f2 | cat > f5
>      Ambiguous output redirect.
> This was from my home directory.  Also, I'm on pebbles and not on
>a hydra machine.  I don't know if that makes a difference.  Anyway,
>is the above sequence correct?


No.  You're not running the Bourne shell.  This is what you should see:

UNIX> /bin/sh
$ cat < f1
This is f1
$ cat f1 f3 > f2
cat: f3: No such file or directory
$ cat f1 f3 2> f2
This is f1
$ cat f1 f3 2>&1 > f2
cat: f3: No such file or directory
$ cat f1 f3 > f2 2>&1
$ cat f1 f3 >&2 2> f2
This is f1
$ cat f1 f3 2> f2 >&2
$ cat f1 f3 2>&1 >f2 | cat > f5

You should check f2 after each command to see what it contains, and then
figure out why it contains what it does.