dos file to linux/unix file

 Removing ^M from file: 

There are several ways to do it

(1) Using Vi editor
     (1-1)  To remove the ^M character, in ViM, write the following in the command mode and press :w to save the changes:

 :set fileformat=unix

    (1-2) Or, type this script in ViM, in the command mode and type :w to save the changes:
   ^V^M gives ^M character in the screen
:1,$s/^V^M//g

(2) Use sed:
     $ sed 's/^M//g' filename > newfilename

(3) Use Dos2Unix
     $ dos2unix filename newfilename

(4) Use col:
     $ cat filename | col -b > newfilename

(5) Use 'tr' :
    $tr -d '\r' < inputfile > outputfile