= n command
.only overwrite method is different with "p" command.
p cmd:paste all chars of the source line.
o cmd:only space chars of destination line are overwritten
by char of corresponding position of source line.
n cmd:only non-space char of source line are selected
and overwrite corresponding position of destination line.
c | : : .
nn |01.23.51-123
0003000|01.23.55-228
0004000|01.24.12-560
0005000|02.13.01-125
0006000|02.43.33-063
nn |03.03.34-970
===>
0001000| : : .
0002000*01:23:51.123
0003000*01:23:55.228
0004000*01:24:12.560
0005000*02:13:01.125
0006000*02:43:33.063