How to open a large log file?

[Benwiggy]

Or you could read it in the Terminal, screen by screen.
Use the command "less" to read a page full at a time. You can move through the file easily.
Type "man less" for full instructions.

You should also try to find out why the log file has not been rotated.

BBEdit can open pretty big files. It may hang for some time, with the SBoD (Spinning Beachball of Death), but usually gets there in the end.