[ILUG] Logging hack wanted

[Jakma, Paul]

> $ cmd 2>&1 | another-cmd
> 
> will pipe both stdout and stderr to another-cmd (in bash, that is).
> There is bound to be a magic incantation to pipe stderr only. 

for the benefit of newer linux users. 
(kenn knows this stuff, but he must have been low on caffeine when he
replied :)

command 2> file-or-pipe

Mini shell redirection tutorial:

n> means redirect file descriptor n. 
fd 1 is normally STDOUT, usually the terminal screen, so command > file
sends output to a file.
fd 2 is normally STDERR, where error messages are sent, usually the terminal
screen.

So to send the output of a command to "output-file", and the error messages
to "error-file", you do:

command > output-file 2> error-file

n>&m means: redirect file desc. n to the same place as file desc. m
Eg, 2>&1 means send STDERR to the same place as where we are sending STDOUT.

command > output 2>&1

means "redirect STDOUT to output, redirect STDERR to the same place as
STDOUT".

To redirect input, eg keyboard, you use < instead of >. Eg:

command < file1 2> output 1>&2

means: "run command, taking it's input from file, send STDERR to output, and
send STDIN to the same place"

etc.. etc... 

-paul.