Remove the history of commands in GNU/Linux shell


For most of the linux users history of commands in shell is a grace. Up/Down arrow
keys help them to find the previously executed commands.But for someothers it may
be a curse.There are situations in which you don’t need to reveal previously used
commands in linux terminal, especially when your system is being used by others.

Linux provides an easy method for removing the history of used commands. Keep it
safe and simple by editing the .bashrc. It is hidden by default in the home folder.

1. Open .bashrc in shell by nano .bashrc
2. Move to the line where
is written.
3. Edit the numbers to look like
4. Now you can logout and check the changes made
by pressing the Up/Down arrow keys.

Recover linux user/root passwords with Backtrack Live CD

ImageBasically the details about the passwords of different users in a linux system are stored in two files namely passwd and shadow. These files are generally located under /etc .Here we make use of these files for recovering the password using the password cracking tool John -The Ripper and is included in Backtrack Linux.

Just follow the steps for recovering the password without resetting the same…

1. Download the ISO image of Backtrack Linux from here
2. Run the ISO image by making it bootable to USB using UNetbootin or writing to CD.
3. Mount the required linux partition to /mnt.(for GUI mode use the command startx)
4. Use the default root prompt to execute the following commands
4.a) unshadow “path to passwd file” “path to shadow file” > newfile
Eg: unshadow /mnt/etc/passwd /mnt/etc/shadow > newfile
4.b) john newfile
5. Passwords for different users will be displayed in a shortwhile.