ISPF Editor: Overlay Line Command

The Overlay Line Command?

The O (overlay) line command is used with the COPY or MOVE line commands. It allows you to copy or move non-blank characters from one line to another line using O (single line) or from multiple lines using OO (block of lines). If a non-blank character is encountered in the destination line(s), it will skip over it, leaving it unchanged.

I will note, for the sake of my sanity, you should reset your bounds before messing with the OVERLAY command. This is because if the destination line has data outside the defined bounds, the OVERLAY command will not affect those columns. For example, let’s say your bounds are set to columns 10 to 60 (for whatever reason), any data in columns 1 to 9 or 61 to 72 will be ignored during the overlay. I haven’t encountered this paraticular issue, but from what I’ve read it can happen, so I thought I’d mention it.

The Dataset

In the example below, we have a dataset containing employee names and IDs. But it’s not very readable. Since this dataset is small, we could manaually add the column separators, but instead, we can use the overlay line command to add them.

000100 |                |                   |                |       |
000200   SMITH            JOHN                JSMITH           34567  
000300   SMITH            SALLY               SSMITH           12345  

How to Overlay One or More Lines

1. First, type C in the prefix area of the first line you want to move or copy data from. But, don’t press Enter just yet!
2. Next, type O in the prefix area of the line you want to overlay. If you want to copy many lines, you can also type a number after the O (e.g., O2).
3. Finally, press Enter to execute the command.

Example: Overlay the first line onto the second.

C00100 |                |                   |                |       |
O00020   SMITH            JOHN                JSMITH           34567  
000300   SMITH            SALLY               SSMITH           12345  

Example: After the overlay, the second line now has the column separators.

000100 |                |                   |                |       |
000200 | SMITH          | JOHN              | JSMITH         | 34567 |
000300   SMITH            SALLY               SSMITH           12345  

How to Overlay a Block of Lines

1. First, type C or M in the prefix area of the first line you want to move or copy data from (e.g., 000100). Again, take your finger off Enter key!
2. Next, type OO in the prefix area of the first line your want to overlay (e.g., 000200).
3. Then, type OO in the prefix area of the last line you want to overlay (e.g., 000300).
4. Finally, slowly place your finger back on the Enter key and press it to execute the action.

Example: Overlay the first line onto the first and second.

C00100 |                |                   |                |       |
OO0200   SMITH            JOHN                JSMITH           34567  
OO0300   SMITH            SALLY               SSMITH           12345  

Example: After the block overlay.

000100 |                |                   |                |       |
000200 | SMITH          | JOHN              | JSMITH         | 34567 |
000300 | SMITH          | SALLY             | SSMITH         | 12345 |

What’s the difference betwene COPY and MOVE?

The difference between the COPY and MOVE commands is that COPY duplicates the data, while MOVE picks it up and moves it to a new location(s).

Summary

In this #kilobit, you learned how to use the OVERLAY line command. Until next time, may the code be with you.