Setting the /etc/sysconfig/network-scripts/ifcfg-usb0 ‘ONBOOT=no’ does not always work and the devices fires up again.

You can disable the NIC from even initializing by adding the following as the first line in /etc/udev/rules.d/60-net.rules
ACTION==”add”, DRIVER==”usb”, SYSFS{configuration}==”CDC Ethernet”, OPTIONS+=”ignore_device, last_rule”

#include 
#include 

int main(int argc, char *argv[])
{
argv[0] = "some_script_path";

setreuid(geteuid(), -1);
execv(argv[0], argv);
exit(1);
}

#!/usr/bin/perl -w
# server.pl
#--------------------

use strict;
use Socket;

# use port 7890 as default
my $port = shift || 7890;
my $proto = getprotobyname('tcp');

# create a socket, make it reusable
socket(SOCKET, PF_INET, SOCK_STREAM, $proto)
or die "Can't open socket $!\n";
setsockopt(SOCKET, SOL_SOCKET, SO_REUSEADDR, 1)
or die "Can't set socket option to SO_REUSEADDR $!\n";

# bind to a port, then listen
bind( SOCKET, pack( 'Sn4x8', AF_INET, $port, "\0\0\0\0" ))
or die "Can't bind to port $port! \n";
listen(SOCKET, 5) or die "listen: $!";
print "SERVER started on port $port\n";

# accepting a connection
my $client_addr;
while ($client_addr = accept(NET_SOCKET, SOCKET)) {
# send them a message, close connection
print NEW_SOCKET "Smile from the server";
close NEW_SOCKET;
} ]]> http://oracle.3dub.com/2011/02/16/perl-network-daemon-for-testing-firewalls-etc/feed/ 0 http://oracle.3dub.com/2011/02/14/change-timezone-in-rhel/ http://oracle.3dub.com/2011/02/14/change-timezone-in-rhel/#comments Mon, 14 Feb 2011 14:58:31 +0000 mgogalla http://oracle.3dub.com/2011/02/14/change-timezone-in-rhel/ mv /etc/localtime /etc/localtime-old

ln -sf /usr/share/zoneinfo/GMT /etc/localtime

hwclock –systohc (or –utc)

This is because by default ssh does not allocate a TTY to run a command. You can force TTY allocation by using the ‘-t’ option to ssh, which will permit backgrounding, and the ssh command will return immediately.

In order to demonstrate, create a file /tmp/sleepy like so:

#!/bin/bash
while ( true ); do
echo `date` “sleep”
sleep 1
done

This command will invoke the script over ssh using nohup and &:

ssh -t localhost ‘nohup /tmp/sleepy &’