you can simply remove the blank line by doing
grep . file1 > file2

Mac line endings are Carriage Returns, so just converting CR to LF should make the file Unix-friendly.

Again, I urge you to search this site if this does not work directly; this question gets asked and answered every week in one form or another.

To remove DOS-style line breaks:

Notice, that "^M" is a literal line break: in vi press "<CTRL>-<V>", then hit <ENTER> to enter it. You will notice that it is a single character rather than two chars.

To remove lines which contain any number of whitespace (Tabs and or blanks):

Enter a literal TAB-char (press <TAB>) and a blank, i just wrote it that way to make it easier to read.

Finally, to find out which unprintable character is bothering you: open the file in vi, enter command mode (press ":") and enter "set list". You will see all the unprintable characters as control codes now (tab characters are represented by "^I" for instance, etc.). Only a blank is now printed as blank char. Enter command mode again and use "set nolist" to switch that off again.

I hope this helps.

bakunin

Or you can use cat with the -v or -A options (somewhat depending on your version of cat), or look at a hex dump with od or xxd or hexdump