[solved] How do I use regular expressions in find / replace

QCAD Professional QCAD 'How Do I' Questions
1

I struggled on this for a while to create the replace term. Other forum posts just show how to use regular expressions in the find field. The following example is to update a series of line numbers on a schematic…
300
301
302
303
304

Find: (3)(\d)(\d)
Replace: 2$2$3

Result:
200
201
202
203
205

Explanation, find the initial digit of 3, and 2 more digits. Replace it with the updated initial digit of 2, and insert the 2nd and 3rd found items.

2

This is resolved, I don’t see how I can mark it so.

3

I have done many times in this way:
Save your file as DXF, its a text file.
For security reason, make a COPY.
Now open the file with REGEX capable text editor (I use Emacs).
Make changes, and reopen with QCAD so you can verify all is fine.
Regards