Linux

by Kulbir Saini on Grub, Hacks, HowTo, Linux, Security

How To: Recover/Crack Root Password when Grub is Locked

The only essential thing is that you should have a Linux boot CD of the same operating system for which you want to crack root password. Some other Linux boot CD may work in some cases. If system is able to boot from the CD, it will take you to a command prompt as shown.

boot:

Type ‘linux rescue’ at this command prompt and enter as shown

boot: linux rescue [Enter]

It will take you to some interface with some questions, answer them properly. The system will go to temporary command prompt. Then issue the following commands

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[bash$] chroot /mnt/sysimage [Enter]
[bash$] cd /boot/grub [Enter]
[bash$] vi menu.lst [Enter]

Now in this file you can see a line beginning with the word ‘password’ remove this line and save the file.

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[bash$]exit
[bash$]exit

Now system will be rebooted and you can see the grub without a password. Don’t forget to remove the CD.

Press ‘e’ at boot screen and again by taking the pointer to the second line press e. Now you can see yourself on a command prompt. Remove ‘rhgb quiet’ from there and write single and press enter.

Now you will come back to the boot screen. Press ‘b’ and system will appear to boot and leave you in command line interface like this.

-bash2-$

Just type passwd like this

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-bash2-$ passwd [Enter]
new password:
retype new password:
passwd: All authentication updated successfully.

Now you have set a new password. Now exit from the shell and system will boot properly in graphical interface.

-bash2-$ exit [Enter]

If there is any error in the procedure please post your suggestions.

 
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:

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#!/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.