Shell Scripting Question

Onyx^ · 04-26-2004, 07:43 AM

Hi all,

I need help with some bash shell scripting questions.. I wonder if any of you could help me... it would be greatly appreciated.

I am trying to write a script that resides in /etc/rcS.d/ that will run during bootup and perform various operations before the network drivers are loaded.

My script 05init_sys is being executed fine.

What I would like within this script is for an action to be performed if the user presses a certain key (for example 'x') during a 5 second delay... If no key is pressed it just continues anyway.

Using a scripting read command causes the system to wait forever until a key is pressed.

Is there a way of acheiving this within bash scripting... ?

Thanks in advance for any help

Ashley Rolleston

hw-tph · 04-26-2004, 07:51 AM

As usual, the Advanced Bash Scripting Guide comes to the rescue.

Håkan

Onyx^ · 04-26-2004, 08:04 AM

thanks hw-tph

Onyx^ · 04-27-2004, 09:15 AM

OK well I have my desired switch working thanks... but now I have another question

I have be able to keep configuration type information (such as IP address etc) in a seperate file, and then get this information from the file during bootup for use in setting up the boot processes (IP for network drivers)

So I have my 05_initsys script which contains the command to run my seperate configuration script. The variable which is set in the configuration script cannot be used back in 05_initsys however

I am guessing this is because when the config script is run it is a child process so that the main script cannot have the variable exported back to it ?

My question is... how can I extract information from a seperate file whilst running a script during startup?

One problem is that I don't have AWK on my embedded system....

Any ideas would be appreciated,

Thanks,

Ashley Rolleston

hw-tph · 04-27-2004, 10:05 AM

You can use the source (no, this is not me making a Star Wars vs open source joke, but it could be) builtin to parse the contents of another file.

Say you have a file called conf with a couple of variables set (I only use one here, but this file could be a whole script):

Code:

string="This is a configuration string or something"

...and in my program I check if the config file is there, and if it is, I source it:

Code:

#!/bin/bash
if [ -f ./conf ]
then
        source ./conf
else
        echo "No configuration file found, aborting. :-("
        exit 1
fi
# Use the variable(s) we sourced from the "conf" file
echo $string
exit 0

You should download the tarball of the ABS Guide, it's invaluable, at least to me.

Håkan

Onyx^ · 04-27-2004, 10:37 AM

thanks once again hw-tph, I will give it a quick try.