locate is a program installed by default that let you search for files/dirs by name, into its database updated with a cron job.
Go through the man page to see other interesting options, like regex search.
Moreover, you can use find to search on the current content of the filesystem (not on a database), with a full set of complicated options, that let you refine your search also based on metadata (permissions, modification time, etc.).
Best Answer
A simple
find / -type f -name ""would do the trick if you know exact filename.find / -type f -iname "filename*"if you want to match more files (ignore case).Avoid
-typeoption if you want to search for directories etc. See manual of find for more information. To see the manual, issue the command:man find