With AWK:
awk '{ sub("\r$", ""); print }' windows.txt > unix.txt
awk 'sub("$", "\r")' unix.txt > windows.txt
With TR
tr -d '\15\32' < winfile.txt > unixfile.txt
:1,$s/^M//g
Convert Files from Linux/Unix Format to Windows and Vice Versa
With AWK:
awk '{ sub("\r$", ""); print }' windows.txt > unix.txt
awk 'sub("$", "\r")' unix.txt > windows.txt
With TR
tr -d '\15\32' < winfile.txt > unixfile.txt
:1,$s/^M//g