On 2 Nov, Hans-Joerg Bibiko wrote:
>
> Dear all,
>
> I have the following problem:
>
> A command will write some data to STDOUT and, maybe, some data to
> STDERR.
>
> To assign a variable to STDOUT:
>
> A=$(command)
>
> To assign a variable to STDERR:
>
> B=$(command 2>&1) # redirect STDERR to STDOUT
>
> OK
>
> But, I want to assign A and B at the same time. But how???
>
> One solution would be the following:
>
> A=$(command 2>&1 temp.file)
> B=$(cat temp.file)
>
> But I don't want to use a additional temporary file for that.
> Can I redirect STDOUT or STERR to a variable directly?
>
> I would be pleased for any hints.
>
> Many thanks in advance
>
> Hans
What an excellent question! Sorry, I don't know. Nested backtics
sound like what you want, except that then the variable defined in the
inner nesting would not be available to the parent shell.
I thought this (below) should work in sh, but it doesn't. Looks like an
assignment is not considered a command, unfortunately:
: /home/luke; a=`ls fergel` 2> /dev/null
ls: fergel: No such file or directory
So even if you marked the inner variable as global in scope, this
wouldn't work:
: /home/luke; a=$(b=$(ls fergle) 2>&1)
ls: fergle: No such file or directory
Ah, of course! Do this (ls is used as an example):
ls -d /tmp fredldf >/tmp/stdout$$ 2> /tmp/stderr$$
read -r A < /tmp/stdout$$
read -r B < /tmp/stderr$$
/bin/rm /tmp/stdout$$ /tmp/stderr$$
echo "A=$A" "B=$B"
The -r avoids backslash interpretation in case you have arbitrary
output, but is not an option in a traditional Bourne shell - you'd need
a more modern one like bash.
Nice puzzle!
luke
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