vi Join two lines and more

In command mode, two lines can be joined, switched and repeated.

J

The J command can be used to join two lines.

Example:

Look at the above snapshot, we need to join first two lines of the above script.

Look at the above snapshot, after pressing J, both the lines are joined.

yyp

The yyp command repeat the current line.

Example:

Look at the above snapshot, our current line is the second line.

Look at the above snapshot, after pressing yyp command, current line is repeated.

ddp

The command ddp swaps two lines (current line and line below the current line).

Example:

Look at the above snapshot, last two lines are swapped from their positions.