By default ubuntu does not have dos2unix and unix2dos commands. But they provide some alternative commands. Those are fromdos and todos. sometimes its hard to switch to new commands. You can solve this issue by creating soft / symbolic links. Here its how to do.
command creation
First you have to find the location for "fromdos". Below command will return the location
which fromdos
Then you have to create a soft/symbolic link for that location with the name "dos2unix"
sudo ln -s /usr/bin/fromdos /usr/bin/dos2unix
Follow the same steps for unix2dos.
To know more about symbolic/soft and hard links click here