September 24, 2006 by Kulbir Saini on Hacks, Linux, Programming, Shell, Tips - Tricks, Wireless

Hack: Mange Fluctuating Wireless

I am trying this small script with a so called gui 😉 . This helps managing my wireless in the extreme conditions. Just a shell script. Run the script as root otherwise it’ll not work.

Get the script here or copy the code below.

#!/bin/bash
#
#	Author - Kulbir Saini, IIIT Hyderabad.
#	Home - http://saini.co.in/
#	KWirelessManger - Just for fun.(It works ... its not just fun).
#
 
#Give the popup life.
POPUP_LIFE="10"
#kdialog --passivepopup "Welcome to 'KWirelessManager'"  ${POPUP_LIFE} &
#Give your device name for proceeding further. It may be one of wlan0, ra0, eth0, ipw2200 etc...
WLAN_DEVICE="wlan0"
#Give your WLAN host to be connected.
WLAN_HOST="IIIT WLAN"
CONNECTED=0
while [[ 1 ]];
do
	iwlist ${WLAN_DEVICE} scanning 2> /dev/null > /tmp/iwlist.aps
	grep -e "Cell" /tmp/iwlist.aps | tr " " "\t" | cut -f15 > /tmp/iwlist.apadd
	ACCESS_POINTS_IN_RANGE=`wc -l /tmp/iwlist.apadd`
	for ACCESS_POINT_ADDRESS in `cat /tmp/iwlist.apadd`
	do
		iwconfig ${WLAN_DEVICE} ap ${ACCESS_POINT_ADDRESS}
		#kdialog --passivepopup "Connceting to Access Point ${ACCESS_POINT_ADDRESS} ..." ${POPUP_LIFE} &
		echo "Connceting to Access Point ${ACCESS_POINT_ADDRESS} ..."
		WLAN_STATUS=`service network restart | tail -1 | grep "FAILED"`
		if [[ ${WLAN_STATUS} == "" ]];
		then
			#kdialog --passivepopup "You are connected to ${WLAN_HOST}." ${POPUP_LIFE} &
			echo "You are connected to ${WLAN_HOST}."
			CONNECTED=1
			break
		else
			#kdialog --passivepopup "Failed to connect to the Access Point ${ACCESS_POINT_ADDRESS} :(" ${POPUP_LIFE} &
			echo "Failed to connect to the Access Point ${ACCESS_POINT_ADDRESS} :("
			CONNECTED=0
		fi
	done
	if [[ ${CONNECTED} == 1 ]];
	then
		sleep 180;
	fi
done

Please suggest any optimization and do tell if u like it.

March 7, 2006 by Kulbir Saini on Email Client, Hacks, Programming, Shell, Tips - Tricks

Hack: Mail Filter – Shell Script

This is an attempt by me to filter mails on a Linux machine. You can run this file on your home directory at mail server and it will help you to sort mails on the basis of

From which user the mail has come or from which domain it came,
to which user or domain mail was sent and
the keywords in the subject part of the mail.

Actually its very slow as shell is very slow , I cant help it . It scan your entire mbox file in the home directory by default. Copy the code and paste in a file say filter.sh and change its permissions to executable. Place it in you home directory at the mail server and run.

Example
You want to see all mails from username@gmail.com just run and it will ask for input,
press 1
From: username [Enter]
It will display all the mails from that are lying there in your mbox one by one.

Get the script here or copy the code below.

#!/bin/bash
#################################
#   Author - Kulbir Saini       #
#   Home - http://sain.ico.in/  #
#################################
 
#shell script to filter mails.
echo -e -n "\033[32mWelcome to the mail filter system \nWhat do you want to do? \nCheck mails on basis of \n1) Sender... \n2) Receiver... \n3) Subject... \n4) Quit... \nPress(1,2,3,4): \033[0m"
read int <&2
while [[ 1 ]];do
while [[ 1 ]];do
count=0;	line=""
if [[ $int == 1 ]];then
	echo -n -e "\033[32mFrom:\033[0m "
	read from <&2
	i=0
	clear
	while read line ;do
	loopbreak=0;	nextmessagestatus=1;	mailtostatus=1;		mailsubstatus=1;	stat=1;
	toecho=`echo $line | grep -E "^From:+" | grep -E "${from}"`
	if [ "$toecho" != "" ];then
		i=`expr $i + 1`
		echo -e "${toecho}"
		while read line ; do
		mailto=`echo $line | grep -E "^To:+"`
		mailsub=`echo $line | grep -E "^Subject:+"`
		if [[ "$mailto" != "" ]] && [[ $mailtostatus == 1 ]];then
			echo $mailto
			mailtostatus=0
		fi
		if [[ "$mailsub" != "" ]] && [[ $mailsubstatus == 1 ]];then
			echo $mailsub
			mailsubstatus=0
		fi
		if [[ $mailtostatus == 0 ]] && [[ $mailsubstatus == 0 ]] && [[ $stat == 1 ]];then
			echo -e "\033[33mStarting of the Message${i}:\033[0m"
			stat=0
		fi
		fromstatus=`echo $line | grep -E "^X-UID:+"`
			if [[ $fromstatus != "" ]];then
			while read line; do
				loopstatus=`echo $line | grep -E "^From +"`
				if [[ $loopstatus != "" ]];then
				loopbreak=1
				break
				fi
				echo $line
			done
			if [[ $loopbreak == 1 ]];then
			echo -e -n "\033[33mEnd of the Message${i}.\nDisplay next message(y/n):\033[0m"
			read messagestatus <&2
			if [[ "$messagestatus" == "y" ]];then
				clear
			else
				nextmessagestatus=0
			fi
			break
			fi
			fi
		done
		count=`expr $count + 1`
	fi
	if [[ $nextmessagestatus == 0 ]];then
		break
	fi
	done
	if [[ $count == 0 ]];then
		echo -e "\033[32mNo mail(s) From: ${from}.\n\033[0m"
	else
		echo -e "\033[32mTotal $count mail(s) From: ${from}.\n\033[0m"
	fi
elif [[ $int == 2 ]];then
	echo -n -e "\033[32mTo: \033[0m"
	read to <&2
	i=0
	clear
	while read line ;do
	loopbreak=0;	nextmessagestatus=1
	toecho=`echo $line | grep -E "^To:+" | grep -E "${to}"`
	if [[ "$toecho" != "" ]];then
		echo -e "$toecho"
		i=`expr $i + 1`
		while read line; do
			tostatus=`echo $line | grep -E "^X-UID:+"`
			if [[ $tostatus != "" ]];then
			echo -e "\033[33mStarting of the Message${i}:\033[0m"
			while read line; do
				loopstatus=`echo $line | grep -E "^From +"`
				if [[ $loopstatus != "" ]];then
				loopbreak=1
				break
				fi
				echo $line
			done
			if [[ $loopbreak == 1 ]];then
			echo -e -n "\033[33mEnd of the Message${i}. \nDisplay next message(y/n): \033[0m"
			read messagestatus <&2
			if [[ $messagestatus == "y" ]];then
				clear
			else
				nextmessagestatus=0
			fi
			break
			fi
			fi
		done
		count=`expr $count + 1`
	fi
	if [[ $nextmessagestatus == 0 ]];then
		break
	fi
	done
	if [[ $count == 0 ]];then
		echo -e "\033[32mNo mail(s) to: ${to}.\n\033[0m"
	else 
		echo -e "\033[32mTotal $count mail(s) To: ${to}.\n\033[0m"
	fi
elif [[ $int == 3 ]];then
	echo -n -e "\033[32mSubject:\033[0m "
 
	read subject <&2
	clear
	i=0
	while read line ;do
	loopbreak=0;	nextmessagestatus=1
	toecho=`echo $line | grep -E "^Subject:+" | grep -E "${subject}"`
	if [[ "$toecho" != "" ]];then
		echo "$toecho"
		i=`expr $i + 1`
		while read line; do
		substatus=`echo $line | grep -E "^X-UID:+"`
		if [[ $substatus != "" ]];then
		echo -e "\033[33mStarting of the Message${i}:\033[0m"
		while read line ; do
			loopstatus=`echo $line | grep -E "^From +"`
			if [[ $loopstatus != "" ]];then
			loopbreak=1
			break
			fi
			echo $line
		done
		if [[ $loopbreak == 1 ]];then
		echo -e -n "\033[33mEnd of the message${i}. \nDisplay next message(y/n): \033[0m"
		read messagestatus <&2
		if [[ $messagestatus == "y" ]];then
			clear
		else
			nextmessagestatus=0
		fi
		break
		fi
		fi
		done
		count=`expr $count + 1`
	fi
	if [[ $nextmessagestatus == 0 ]];then
		break
	fi
	done
	if [[ $count == 0 ]];then
		echo -e "\033[32mNo mail(s) with Subject: ${subject}.\n\033[0m"
	else
		echo -e "\033[32mTotal $count mail(s) with Subject: ${subject}.\033[0m\n"
	fi
elif [[ $int == 4 ]];then
	echo -e "\033[32mThank you for using this utility. \nPlease visit again.\033[0m"
	exit
else
	echo -e "\033[32mI could not understand that. \nPlease try again.\033[0m\n"
fi
echo -e -n "\033[32m1) Sender... \n2) Receiver... \n3) Subject... \n4) Quit... \nPress(1,2,3,4):\033[0m "
read int <&2
break
done < mbox 
done

#!/bin/bash ################################# # Author - Kulbir Saini # # Home - http://sain.ico.in/ # ################################# #shell script to filter mails. echo -e -n "\033[32mWelcome to the mail filter system \nWhat do you want to do? \nCheck mails on basis of \n1) Sender... \n2) Receiver... \n3) Subject... \n4) Quit... \nPress(1,2,3,4): \033[0m" read int <&2 while [[ 1 ]];do while [[ 1 ]];do count=0; line="" if [[ $int == 1 ]];then echo -n -e "\033[32mFrom:\033[0m " read from <&2 i=0 clear while read line ;do loopbreak=0; nextmessagestatus=1; mailtostatus=1; mailsubstatus=1; stat=1; toecho=`echo $line | grep -E "^From:+" | grep -E "${from}"` if [ "$toecho" != "" ];then i=`expr $i + 1` echo -e "${toecho}" while read line ; do mailto=`echo $line | grep -E "^To:+"` mailsub=`echo $line | grep -E "^Subject:+"` if [[ "$mailto" != "" ]] && [[ $mailtostatus == 1 ]];then echo $mailto mailtostatus=0 fi if [[ "$mailsub" != "" ]] && [[ $mailsubstatus == 1 ]];then echo $mailsub mailsubstatus=0 fi if [[ $mailtostatus == 0 ]] && [[ $mailsubstatus == 0 ]] && [[ $stat == 1 ]];then echo -e "\033[33mStarting of the Message${i}:\033[0m" stat=0 fi fromstatus=`echo $line | grep -E "^X-UID:+"` if [[ $fromstatus != "" ]];then while read line; do loopstatus=`echo $line | grep -E "^From +"` if [[ $loopstatus != "" ]];then loopbreak=1 break fi echo $line done if [[ $loopbreak == 1 ]];then echo -e -n "\033[33mEnd of the Message${i}.\nDisplay next message(y/n):\033[0m" read messagestatus <&2 if [[ "$messagestatus" == "y" ]];then clear else nextmessagestatus=0 fi break fi fi done count=`expr $count + 1` fi if [[ $nextmessagestatus == 0 ]];then break fi done if [[ $count == 0 ]];then echo -e "\033[32mNo mail(s) From: ${from}.\n\033[0m" else echo -e "\033[32mTotal $count mail(s) From: ${from}.\n\033[0m" fi elif [[ $int == 2 ]];then echo -n -e "\033[32mTo: \033[0m" read to <&2 i=0 clear while read line ;do loopbreak=0; nextmessagestatus=1 toecho=`echo $line | grep -E "^To:+" | grep -E "${to}"` if [[ "$toecho" != "" ]];then echo -e "$toecho" i=`expr $i + 1` while read line; do tostatus=`echo $line | grep -E "^X-UID:+"` if [[ $tostatus != "" ]];then echo -e "\033[33mStarting of the Message${i}:\033[0m" while read line; do loopstatus=`echo $line | grep -E "^From +"` if [[ $loopstatus != "" ]];then loopbreak=1 break fi echo $line done if [[ $loopbreak == 1 ]];then echo -e -n "\033[33mEnd of the Message${i}. \nDisplay next message(y/n): \033[0m" read messagestatus <&2 if [[ $messagestatus == "y" ]];then clear else nextmessagestatus=0 fi break fi fi done count=`expr $count + 1` fi if [[ $nextmessagestatus == 0 ]];then break fi done if [[ $count == 0 ]];then echo -e "\033[32mNo mail(s) to: ${to}.\n\033[0m" else echo -e "\033[32mTotal $count mail(s) To: ${to}.\n\033[0m" fi elif [[ $int == 3 ]];then echo -n -e "\033[32mSubject:\033[0m " read subject <&2 clear i=0 while read line ;do loopbreak=0; nextmessagestatus=1 toecho=`echo $line | grep -E "^Subject:+" | grep -E "${subject}"` if [[ "$toecho" != "" ]];then echo "$toecho" i=`expr $i + 1` while read line; do substatus=`echo $line | grep -E "^X-UID:+"` if [[ $substatus != "" ]];then echo -e "\033[33mStarting of the Message${i}:\033[0m" while read line ; do loopstatus=`echo $line | grep -E "^From +"` if [[ $loopstatus != "" ]];then loopbreak=1 break fi echo $line done if [[ $loopbreak == 1 ]];then echo -e -n "\033[33mEnd of the message${i}. \nDisplay next message(y/n): \033[0m" read messagestatus <&2 if [[ $messagestatus == "y" ]];then clear else nextmessagestatus=0 fi break fi fi done count=`expr $count + 1` fi if [[ $nextmessagestatus == 0 ]];then break fi done if [[ $count == 0 ]];then echo -e "\033[32mNo mail(s) with Subject: ${subject}.\n\033[0m" else echo -e "\033[32mTotal $count mail(s) with Subject: ${subject}.\033[0m\n" fi elif [[ $int == 4 ]];then echo -e "\033[32mThank you for using this utility. \nPlease visit again.\033[0m" exit else echo -e "\033[32mI could not understand that. \nPlease try again.\033[0m\n" fi echo -e -n "\033[32m1) Sender... \n2) Receiver... \n3) Subject... \n4) Quit... \nPress(1,2,3,4):\033[0m " read int <&2 break done < mbox done

December 8, 2005 by Kulbir Saini on Hacks, HowTo, Linux, Shell, SSH

How To: RSA Key Generation for Remote Host

Using RSA key of a remote machine you can authenticate for SSH for that machine without entering a password. Generating RSA key is very easy and simple. Follow the procedure below to generate keys for two machine. Machies: 1) mirage (192.168.36.205) and students (192.168.36.200).

Step 1
use this command on mirage server

[kulbir@mirage ~] ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
32:30:af:c6:0b:e2:c0:60:92:fd:62:da:37:32:f2:ce root@LocalHost

You should get the result as above and if it asks to overwrite something then overwrite it.

Step 2

1 2	[kulbir@mirage ~] scp ~/.ssh/id_rsa.pub user@192.168.36.200:~/.ssh/authorized_keys2 user@192.168.36.200''s password:

Now if the above operation was successful, then you can login from your mirage account to your students account without a password. Try it, and if it is successful then do the same for your students server. Now you don’t need type your password again and again to login from one server to the other.

If the above worked for you, then there is one more thing you can try out. Go to .ssh/ directory in your home directory and create a file named ‘config’. Now write in that file

host students
hostname 192.168.36.200
port 22
user kulbirsaini

and save the file. You have to specify the port on which SSH is listening. Save this file and now you can login by just typing

[kulbir@mirage ~] ssh students [Enter]

You can write whatever you want in place of ‘students’ in the file and then login typing ssh ‘word’ that you have written against the host in file.

December 3, 2005 by Kulbir Saini on Hacks, Linux, Programming, Shell, Tips - Tricks

Hack: Graphical Implementation of CP Command

To use this graphical interface do as directed below:

#!/bin/bash
##############################
# Author - Kulbir Saini      #
# Home - http://saini.co.in/ #
##############################
 
if [ $1 == -i ] || [ $1 == -f ];then          
	if [ ! -s $2 ] && [ ! -f $2 ] && [ ! -d $2 ];then
		dialog --title "Copy daemon" --backtitle "copy:" --infobox "file:$2 doesn't exist.\nCan't copy...\nPress any key..." 5 30; read
	elif [ ! $3 ];then
		dialog --title "Copy daemon" --backtitle "copy:" --infobox "Invalid arguements...\nCan't copy...\nPress any key..." 5 30; read
	elif [ -d $3 ];then
		dialog --title "Copy daemon" --backtitle "copy:" --infobox "$3: is a directory.\nCan't copy...\nPress any key..." 5 30; read
	elif [ -d $2 ];then
		dialog --title "Copy daemon" --backtitle "copy:" --infobox "$2: is a directory.\nCan't copy...\nPress any key..." 5 30; read
	elif [ -s $3 -o -f $3 ];then
		dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to overwrite file:$3" 10 60;
		select=$?
		case $select in 
			0) echo -e "i'm ordered to overwrite file:$3 \noverwriting...\noverwritten file:$3" ; cp -f $2 $3 ;;
			1) echo "i'm ordered not to overwrite.";;
			255) echo "cancelled by you by pressing [Esc].";;
		esac
	else
		dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to copy the file:$2 to file:$3" 10 60 ;
		select1=$?
		case $select1 in
			0) echo -e "i'm ordered to copy file:$2 to file:$3 \ncopying...\ncopied to file:$3" ; cp $2 $3 ;;
			1) echo "i'm ordered not to copy.";;
			255) echo "cancelled by you by pressing [Esc].";;
		esac
	fi
elif [ ! -s $1 ] && [ ! -f $1 ] && [ ! -d $1 ];then
	dialog --title "Copy daemon" --backtitle "copy:" --infobox "file:$1 doesn't exist.\nCan't copy...\nPress any key..." 5 30; read
elif [ ! $2 ];then
	dialog --title "Copy daemon" --backtitle "copy:" --infobox "Invalid arguements...\nCan't copy...\nPress any key..." 5 30; read
elif [ -d $2 ];then
	dialog --title "Copy daemon" --backtitle "copy:" --infobox "$2: is a directory.\nCan't copy...\nPress any key..." 5 30; read
elif [ -d $1 ];then
	dialog --title "Copy daemon" --backtitle "copy:" --infobox "$1: is a directory.\nCan't copy...\nPress any key..." 5 30; read
elif [ -s $2 -o -f $2 ];then
	dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to overwrite file:$2" 10 60;
	select=$?
	case $select in 
		0) echo -e "i'm ordered to overwrite file:$2 \noverwriting...\noverwritten file:$2" ; cp -f $1 $2 ;;
		1) echo "i'm ordered not to overwrite.";;
		255) echo "cancelled by you by pressing [Esc].";;
	esac
else
	dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to copy the file:$1 to file:$2" 10 60 ;
	select1=$?
	case $select1 in
		0) echo -e "i'm ordered to copy file:$1 to file:$2 \ncopying...\ncopied to file:$2" ; cp $1 $2 ;;
		1) echo "i'm ordered not to copy.";;
		255) echo "cancelled by you by pressing [Esc].";;
	esac
fi

#!/bin/bash ############################## # Author - Kulbir Saini # # Home - http://saini.co.in/ # ############################## if [ $1 == -i ] || [ $1 == -f ];then if [ ! -s $2 ] && [ ! -f $2 ] && [ ! -d $2 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "file:$2 doesn't exist.\nCan't copy...\nPress any key..." 5 30; read elif [ ! $3 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "Invalid arguements...\nCan't copy...\nPress any key..." 5 30; read elif [ -d $3 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "$3: is a directory.\nCan't copy...\nPress any key..." 5 30; read elif [ -d $2 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "$2: is a directory.\nCan't copy...\nPress any key..." 5 30; read elif [ -s $3 -o -f $3 ];then dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to overwrite file:$3" 10 60; select=$? case $select in 0) echo -e "i'm ordered to overwrite file:$3 \noverwriting...\noverwritten file:$3" ; cp -f $2 $3 ;; 1) echo "i'm ordered not to overwrite.";; 255) echo "cancelled by you by pressing [Esc].";; esac else dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to copy the file:$2 to file:$3" 10 60 ; select1=$? case $select1 in 0) echo -e "i'm ordered to copy file:$2 to file:$3 \ncopying...\ncopied to file:$3" ; cp $2 $3 ;; 1) echo "i'm ordered not to copy.";; 255) echo "cancelled by you by pressing [Esc].";; esac fi elif [ ! -s $1 ] && [ ! -f $1 ] && [ ! -d $1 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "file:$1 doesn't exist.\nCan't copy...\nPress any key..." 5 30; read elif [ ! $2 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "Invalid arguements...\nCan't copy...\nPress any key..." 5 30; read elif [ -d $2 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "$2: is a directory.\nCan't copy...\nPress any key..." 5 30; read elif [ -d $1 ];then dialog --title "Copy daemon" --backtitle "copy:" --infobox "$1: is a directory.\nCan't copy...\nPress any key..." 5 30; read elif [ -s $2 -o -f $2 ];then dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to overwrite file:$2" 10 60; select=$? case $select in 0) echo -e "i'm ordered to overwrite file:$2 \noverwriting...\noverwritten file:$2" ; cp -f $1 $2 ;; 1) echo "i'm ordered not to overwrite.";; 255) echo "cancelled by you by pressing [Esc].";; esac else dialog --title "Copy daemon" --backtitle "copy:" --yesno "Do you want to copy the file:$1 to file:$2" 10 60 ; select1=$? case $select1 in 0) echo -e "i'm ordered to copy file:$1 to file:$2 \ncopying...\ncopied to file:$2" ; cp $1 $2 ;; 1) echo "i'm ordered not to copy.";; 255) echo "cancelled by you by pressing [Esc].";; esac fi

1. Get the script here .

2. Move it to a file named ‘copy’.

3. Create a director ‘bin’ in your home directory.

4. Write

export PATH=$PATH:${HOME }/bin/

to your ~/.bashrc file.

5. Execute .bashrc by issuing

[saini@localhost ~]# . .bashrc

6. If you want to copy a file foo.txt to bar.txt then do it as

[saini@localhost ~]# copy foo.txt bar.txt [Enter]

Done.

Tech Stuff

How Tos, Tutorials, Tips and Tricks

Bash

Hack: Mange Fluctuating Wireless

Hack: Mail Filter – Shell Script

Hack: Graphical Implementation of CP Command