Install mlocate for quick file search in Linux
mlocate is a useful tool for quickly find files on the filesystem based on their name.
# sudo apt-get install mlocate
After install, you would need to build the database for the first time
# sudo updatedb&
Now the database building/indexing is running in the background, when it is finished, you can use the locate command to lookup file in your filesystem.
# locate SHA1.pm /usr/lib/perl5/Digest/SHA1.pm