vi common commands

vi_common_commands

    i - Insert at cursor (goes into insert mode)
    a - Write after cursor (goes into insert mode)
    A - Write at the end of line (goes into insert mode)
    ESC - Terminate insert mode
    u - Undo last change
    U - Undo all changes to the entire line
    o - Open a new line (goes into insert mode)
    dd - Delete line
    3dd - Delete 3 lines.
    D - Delete contents of line after the cursor
    C - Delete contents of a line after the cursor and insert new text. Press ESC key to end insertion.
    dw - Delete word
    4dw - Delete 4 words
    cw - Change word
    x - Delete character at the cursor
    r - Replace character
    R - Overwrite characters from cursor onward
    s - Substitute one character under cursor continue to insert
    S - Substitute entire line and begin to insert at the beginning of the line
    ~ - Change case of individual character

Moving within a file

    k - Move cursor up
    j - Move cursor down
    h - Move cursor left
    l - Move cursor right

You can also use the arrow keys on the keyboard. 

 Saving and Closing the file

    Shift+zz - Save the file and quit
    :w - Save the file but keep it open
    :q - Quit without saving
    :wq - Save the file and quit