Vim editing:
vi test.txt
i to insert
:w to save
:q to quit
:wq to save and quit
Shift+zz - Save the file and quit
You should be in the "command mode" to execute these 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