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Top Forums Shell Programming and Scripting Redirect string from bash stderr to user stdin Post 302998209 by fredestet on Saturday 27th of May 2017 09:28:40 AM
Old 05-27-2017
Redirect string from bash stderr to user stdin

Hi there,

I need to execute a command in the bash. The program prints some standard (output and) error and then wants the user to choose one of several options and type the according input. I am trying to solve this issue in a bash script but also running into some circular dependency. How can I combine these two things to a single bash call with only one execution of command? For the user input, i would usually write something like
Code:
echo $input | command

But $input must be read from stderr of command in advance which I would usually read as
Code:
input=$(command 2>&1 > /dev/null | awk '/some.*regexp$/ {print $2}')

I particularly don't want to execute command twice (once for extracting/saving the content of $input and once for feeding command with that input). Is there a way to combine the two calls in one? (BTW: both single commands work as I need them since I want to read from the stderr and don't need stdout at all.)

Many thanks in advance!
 

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COMMAND-NOT-FOUND(1)					    http://en.opensuse.org/Sco					      COMMAND-NOT-FOUND(1)

NAME
command-not-found - A command-not-found handler SYNOPSIS
command-not-found {binary_name} {repository} ARGUMENTS
The following arguments are required: binary_name The name of binary you are looking for. repository The name of repository for search. For most cases, use zypp DESCRIPTION
command-not-found handler is designed to tell users which package contains a missing command. The handler is integrated to bash(1) and zsh(1) shells and is not necessary to call it directly. Just type a name of the command in your favourite shell and you'll get a result. If you consider c-n-f handler useless, just add unset command_not_found_handle to your profile or remove the command-not-found package. Handler doesn't call the command-not-found binary directly, it only prints info about it. If you want to invoke it automatically, just add export COMMAND_NOT_FOUND_AUTO=1 to your bash profile. EXAMPLE
: NORMAL USAGE For example you want to try blender, because you have heard that is an amazing program. So just type blender in shell: $ blender You get the following output: The program 'blender' can be found in the following package: * blender [ path: /usr/bin/blender, repository: zypp (openSUSE 11.1-0) ] Try installing with: sudo zypper install blender bash: blender: command not found SEE ALSO
scout(1) AUTHOR
Pavol Rusnak <stick@gk2.sk> Developer http://gitorious.org/opensus 08/07/2009 COMMAND-NOT-FOUND(1)
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