= b command
.set destination to the previous line of "b" command line,
then exexute "a" command.
See "a" command for effect of n,b,s.
.copy just before the line.
c3 |A
0000002|B
0000003|C
0000004|D
0000005|E
b |F
0000007|G
===>
0001000|A
0002000|B
0003000|C
0004000|D
0005000|E
0005100*A
0005200*B
0005300*C
0006000|F
0007000|G