Bulk rename filenames
Install Thunar
Thunar is the devault filemanager of XFCE. It can be easily installed using sudo apt-get install thunar
But be aware that a lot of XFCE files come along with this installation as Thunar depends on them.
Install Metamorphose 2
This is the most advanced of al available bulk renamers. Metamorphose 2 binaries for Linux (deb and rpm) and Windows are available on SourceForge.
Because these binaries are are pretty old (2011), you can grab the latest version source (which dates to August, 2015) from GitHub.
Ubuntu 15.10 and newer users can install the latest Metamorphose 2 by using the main WebUpd8 PPA:
sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install metamorphose2
Install pyRenamer
On Ubuntu, install it using the following command, but be aware that the program isn't developed anymore:
sudo apt-get install pyrenamer
Nemo
In Nemo the F2 key opens a bulk renamer option that qorks quite fine.