I have long list of two string in every row, numerical string and alphanumerical string (that are of different length in every raw), that I want to change (switch) position:

```
010110,file_1.txt
0120100,file_11.txt

```

To have this:

```
file_1.txt,010110
file_11.txt,0120100

```

Second string also include dots and underscores, as in example above.
I tried regex that I used before for similar task but it doesn't work, I tried in Notepad++ and Powergrep.

```
([^_]*),(.*)

```

Replace with:

```
\2_\1

```

Tried that regex (with variations) but didn't have result.