Ubuntu 14.04 : How do you use mount.cifs, mount.nfs, they are not in the repositories any more?

The mount.cifs command is provided by cifs-utils and mount.nfs by nfs-common.

In general, when you're looking for a particular file and don't know which package provides it, you can search in the Ubuntu Repositories or in synaptic. Alternatively, you can use apt-file.

If it is not installed, install it with sudo apt-get install apt-file and then update its database with apt-file update. Once you've done that, you can easily search package contents:

$ apt-file search mount.cifs mount.nfs
cifs-utils: /sbin/mount.cifs
cifs-utils: /usr/share/man/man8/mount.cifs.8.gz
$ apt-file search mount.nfs
manpages-fr-extra: /usr/share/man/fr/man8/mount.nfs.8.gz
manpages-fr-extra: /usr/share/man/fr/man8/umount.nfs.8.gz
nfs-common: /sbin/mount.nfs
nfs-common: /sbin/mount.nfs4
nfs-common: /sbin/umount.nfs
nfs-common: /sbin/umount.nfs4
nfs-common: /usr/share/man/man8/mount.nfs.8.gz
nfs-common: /usr/share/man/man8/umount.nfs.8.gz