Find a file named postgresql.conf
find / -name postgresql.conf

Find a file named postgresql.conf (case-insensitive)
find / -iname postgresql.conf

Find a file named postgresql.conf
find / -type f -name postgresql.conf

Find a file based on wildcard and cp to a specified folder
find . -name "*20150727*" -exec cp {} ../verify \;

Find a file based on the extension
find . -name '*.swp' -print0

Find and delete all swap files
find . -type f -name ".*.swp" -exec rm -f {} \;

Locate a file named recovery.sh
updatedb
locate recovery.sh