[clue-tech] Error messages that can't be redirected

[Jim Ockers]

Oh error messages can always be redirected, but sometimes you have to 
try harder than others:

basic: command 1>/dev/null 2>/dev/null
or: command 2>&1 >/dev/null

This almost always wins:  sh -c "command 2>&1 >/dev/null" 2>&1 >./dev/null

You can keep nesting the sh levels and forcing redirect to /dev/null (or 
your output file) if you still get output you weren't expecting.

Matt Gushee wrote:
> Hi folks--
>
> Here's something that's been bugging me for a long time: sometimes I 
> will use a command-line program and try to redirect the output, e.g. 
> to a log file, and it doesn't work. For example:
>
>   for img in *.jpg; do
>     nice gm convert -resize 160x160 $img thumbs/$img >> resize.log 2>&1
>   done
>
> Nope. I get nothing in my log file. I've tried several variations of 
> this command, including piping the output to tee. It just doesn't ever 
> work. 'gm', by the way, is GraphicsMagick, a better-performing fork of 
> ImageMagick. The same thing happened with ImageMagick, and IIRC with 
> some other programs I've used on occasion.
>
> So what's going on here?
>