vi filename
Command Mode
hjkl
the right on the lower left
the current line dd
yy copy
line on the next line p adhesive paste P
A is inserted in a cursor inserted at the end when the row
i inserted before the cursor when inserted into the first row I
o O insert inserted below the current line on the line
Edit mode
:
The last line mode
: set nu show line numbers
: w save
: wq to save and exit
: q quit without saving!