Display X applications from virtual terminals

Here is a script that can help you set the proper envirionment to start a gnome-shell from one of the terminals.

#!/bin/bash - 
#===============================================================================
#
# FILE: xenv.sh
# 
# USAGE: ./xenv.sh 
# 
# DESCRIPTION: http://live.gnome.org/GnomeShell/Debugging
#
# 
# OPTIONS: ---
# REQUIREMENTS: ---
# BUGS: ---
# NOTES: ---
# AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
# CREATED: 09/14/2011 04:45:31 PM IST
# Last modified: Wed Sep 14, 2011 04:45PM
# REVISION: ---
#===============================================================================

gnome_session=$(pgrep -u $USER gnome-session)
eval export$(sed's/\o000/\n/g;' < /proc/$gnome_session/environ |grep DISPLAY)
eval export$(sed's/\o000/\n/g;' < /proc/$gnome_session/environ |grep XAUTHORITY)
eval export$(sed's/\o000/\n/g;' < /proc/$gnome_session/environ |grep DBUS_SESSION_BUS_ADDRESS)

So, once you have done that you have the correct environment to use the X display and thus you can start the gnome-shell as well or do any other fancy thing that you want 🙂

colors in bash scripts

I have been trying to understand the color codes for bash for a pretty long time, but somehow never got time to understand this clearly. So this time around when I was writing a script to analyze some logs. I thought I will give it a go and finally understood some part of this.

So, first we will start with this script. This is taken from here.

systemadm – simpler way to manage the service files for systemd

Once the systemd unit and service files have come into being, understanding of the system services have changed a little bit and it might require some time to understand the cli tools for managing these services and units. That being the case, systemadm comes to rescue. This is a simple tool which :

Graphical front-end for systemd.

For installation :

sudo yum install systemd-gtk

And here’s a screenshot::

Convert string to hex.

If you want to use snoop or tcpdump with advanced search in the packet, then you would need to convert the string to hex string. For this, either you can use a web search and find some web application to do that or you can use a simple C program like this 🙂

/*
* =====================================================================================
*
*       Filename:  ascii.c
*
*    Description:  ascii to dec
*
*        Version:  1.0
*        Ceated:  03/02/2012 12:08:49 PM
*       Revision:  none
*       Compiler:  gcc
*
*         Author:  Amit Agarwal (aka), amit.agarwal@roamware.com
*  Last modified: Thu Mar 08, 2012  08:47PM
*
* =====================================================================================
*/
void main (int argc, char **argv){
    int i=0;
    char a[200]="",b[200]="";
    printf("String - %s, Length - %d\n",argv[1],strlen(argv[1]));
    /*printf("%x\n 0x",argv[1]);*/
    while (i < strlen(argv[1])){
        /*printf("%c",argv[1][i]);*/
        sprintf(a,"%s%x",a,argv[1][i]);
        /*printf("a=%s\n",a);
        printf("b=%s\n",b);*/
        sprintf(b,"%s%d",b,argv[1][i]);
        i++;
    }
    printf ("\n");
    printf ("String : %s\n",argv[1]);
    printf ("Hex    : 0x%s\n", a);
    printf ("Dec    : %s\n", b);

}

Related articles

• Re: iis bug (seclists.org)
• Problem of file transfer in socket programming (daniweb.com)
• [Unix C] ECHO Implementation (jetcracker.wordpress.com)
• Character Stuffing in C (sourcecode4all.wordpress.com)

Your own local search engine.

There are times when you would want to have a local search engine capable of indexing even pdf and doc files. So here is a solution.

You can use “Omega” and here are the instructions.

download omega from http:// xapian.org/download

yum install xapian libuuid-devel

And then make and install omega and for this you can follow the instructions.

Create index using command omindex
and then you can use quest or search.py to search or you can setup the cgi way so that you can use local browser to search.

uptimed – keep track of your system uptime.

Uptimed is an up time record daemon keeping track of the highest
up times the system ever had.

Uptimed has the ability to inform you of records and milestones
though syslog and e-mail, and comes with a console front end to
parse the records, which can also easily be used to show your
records on your Web page

Installation :

sudo yum install uptimed

Once installed, you will have to first create the boot id with this command:

pigz -parallel gzip

Here is a short description of pigz:

pigz, which stands for parallel implementation of gzip,
is a fully functional replacement for gzip that exploits
multiple processors and multiple cores to the hilt when compressing data.

And for the installation:

sudo yum install pigz

With pigz, if you don’t have many things running on your multi processor machine then you will see a significant improvement when you are gzipping the files.