TJ TechGuide

===Change Forgotten Root Password in Ubuntu=== 1) reboot the ubuntu pc and press the "Esc" key 2) press 'e' key to edit the menu 3) now replace the text line "ro quiet splash $vt_handoff" with "rw init=/bin/bash" 4) press:ctrl+x  5) type "mount | grep -w /" command 6) type "passwd" 7) then type your new password 8) retype the new password 9) type "exec /sbin/init"

Basic ubuntu commands and shortcuts for daily usage Shortcuts   ctrl +alt    +t    open a terminal ctrl +alt    +l    lock the pc ctrl +shift +t    open a new tab ctrl +shift +w  quit in current tab ctrl +shift +q   quit from terminal ctrl +shift +f    to find something ctrl +q              close application alt  +tab          switch applications f11                    full screen Commands pwd           print working directory cd              change directory mkdir        make directory rmdir         remove directory ./                execute a file touch       create a file rm             delete a file exit            do exit action cd ..          go to previous directory cat            open a file free            check the memory ifconfig      interface configuration xrandr -q   current screen resolution xrandr -s   set a new screen resolution grep           search text history       display all entered list of commands ls     

Data Types Data types can mainly be divided into two types. They are primitive and non-primitive data types. Here are more details about primitive data types. boolean - It is a binary variable that can have two possible values.  Size= 1 bit.    Ex: - True(1) or False(0) char        - It is a character data type.  Size= 2 bytes.                   Ex: - character, letter, ASCII value byte        - It is a numeric data type.  Size= 1 bytes. short      - It is a numeric data type.  Size= 2 bytes. int           - It is a numeric data type.  Size= 4 bytes. long        - It is a numeric data type.  Size= 8 bytes. float        - It is a fractional data type.  Size= 4 bytes. double     - It is a fractional   data type.  Size= 8 bytes. Here are some details about non-primitive data types. String      - Including characters, spaces and numbers. Array       - It is a data structure that can store a group of elements.