$ tr :: Translate the character in string1 from stdin into those in string2 in stdout.


$ sed :: This command is used for editing files from a script or from the command line.

$ head :: Display first 'N' number of files.



$ tail :: Display last 'N' number of files.



$ cmp :: Compare two files andd list where differences occur.



$ diff :: Compare the two files and shows the difference.



$ wc :: Display word (or character or line ) count for file.