The files in /etc/skel are for the creation of new user accounts, but if they are deleted accidentally, they are no good no anyone. This is how to re-download these files and restore them.
Firstly, download the bash package to an empty directory.
ason@Yog-Sothoth » bash » $ apt download bash
Then extract it to that directory.
jason@Yog-Sothoth » bash » $ dpkg -x bash_4.4.18-2ubuntu1_amd64.deb .
Now we have all the files we need.
jason@Yog-Sothoth » bash » $ ls -hula etc/skel/ total 20K drwxr-xr-x 2 jason jason 4.0K Jun 21 10:08 . drwxr-xr-x 3 jason jason 4.0K Jun 21 10:08 .. -rw-r--r-- 1 jason jason 220 Jun 21 09:55 .bash_logout -rw-r--r-- 1 jason jason 3.7K Jun 21 09:55 .bashrc -rw-r--r-- 1 jason jason 807 Jun 21 09:55 .profile
Just copy the files into /etc/skel and they are restored. This is an easy way to fix this issue.