= j command
        .concatinate the lines.

      (1) x[n][,b][,s] pattern

        .repeat 5 times to concatinate each 2 lines

            j5     |  A
            0002000|  B
            0003000|  C
            0004000|  D
            0005000|  E
            0006000|  F
            0007000|  G
            0008000|  H
            0009000|  I
            0010000|  J
            0011000|  K
            0012000|  L
        ===>
            0001000*  A  B
            0003000*  C  D
            0005000*  E  F
            0007000*  G  H
            0009000*  I  J
            0011000|  K
            0012000|  L

        .repeat 4 times to repeat 3 times concatination of 2 lines
         and to skip 1 line.

            j4,3.1 |  A
            0002000|  B
            0003000|  C
            0004000|  D
            0005000|  E
            0006000|  F
            0007000|  G
            0008000|  H
            0009000|  I
            0010000|  J
            0011000|  K
            0012000|  L
            0013000|  M
            0014000|  N
            0015000|  O
            0016000|  P
            0017000|  Q
            0018000|  R
            0019000|  S
            0020000|  T
            0021000|  U
            0022000|  V
            0023000|  W
            0024000|  X
            0025000|  Y
            0027000|  0
            0028000|  1
            0029000|  2
            0030000|  3
        ===>
      r1 b1 0001000*  A  B
         b2 0003000*  C  D
         b3 0005000*  E  F
         s1 0007000|  G
      r2 b1 0008000*  H  I
         b2 0010000*  J  K
         b3 0012000*  L  M
         s1 0014000|  N
      r3 b1 0015000*  O  P
         b2 0017000*  Q  R
         b3 0019000*  S  T
         s1 0021000|  U
      r4 b1 0022000*  V  W
         b2 0024000*  X  Y
         b3 0026000*  Z  0
            0028000|  1
            0029000|  2
            0030000|  3

      (2) xx-xx[n][,b][.s] pattern

        .repeat in the range to concatinate each 2 lines

            jj     |  A
            0002000|  B
            0003000|  C
            0004000|  D
            jj     |  E
            0006000|  F
            0007000|  G
            0008000|  H
        ===>
            0001000*  A  B
            0003000*  C  D
            0005000|  E
            0006000|  F
            0007000|  G
            0008000|  H

        .repeat in the range to repeat 3 times concatination of 2 lines
         and to skip 1 line.

            jj,3   |  A
            0002000|  B
            0003000|  C
            0004000|  D
            0005000|  E
            0006000|  F
            0007000|  G
            0008000|  H
            0009000|  I
            0010000|  J
            0011000|  K
            0012000|  L
            0013000|  M
            0014000|  N
            0015000|  O
            0016000|  P
            0017000|  Q
            jj.1   |  R
            0019000|  S
            0020000|  T
        ===>
      rr b1 0001000*  A  B
         b2 0003000*  C  D
         b3 0005000*  E  F
         s1 0007000|  G
      rr b1 0008000*  H  I
         b2 0010000*  J  K
         b3 0012000*  L  M
         s1 0014000|  N
      rr b1 0015000*  O  P
         b2 0017000*  Q  R
            0019000|  S
            0020000|  T

        .repeat in the range to repeat 2 times concatination of 3 lines
         and to skip 1 line.

            jj3    |  A
            0002000|  B
            0003000|  C
            0004000|  D
            0005000|  E
            0006000|  F
            0007000|  G
            0008000|  H
            0009000|  I
            0010000|  J
            0011000|  K
            0012000|  L
            0013000|  M
            0014000|  N
            0015000|  O
            0016000|  P
            0017000|  Q
            jj,2.1 |  R
            0019000|  S
        ===>
      rr b1 0001000*  A  B  C
         b2 0004000*  D  E  F
         s1 0007000|  G
      rr b1 0008000*  H  I  J
         b2 0011000*  K  L  M
         s1 0014000|  N
      rr b1 0015000*  O  P  Q
            0018000|  R
            0019000|  S