how to replace "new line" character?

[vvsalon]

I want to make the content in my files into one line only,
how can Textpad help me?
my version is 4.1
thx all!!!

[Ed]

In v4.5
Ctrl-A (to select all)
Ctrl-J (join lines)

[Roy Beatty]

If you perform Ctrl-A, Ctrl-J on a file with thousands of lines, resulting in a single line more than a few thousand characters long, then Regular Expression replace operations may take a very long time.

Roy