Find syntax example

How do I find files in a directory and subdirectories and execute a command that takes found file(s) as parameter?

Easiest way is to run find command and then pipe the output to the xargs command:
find [start_dir] -name [file_mask] | xargs -I [repl_symbol] [command]

• find [start_dir] - start from specified directory (find scans subdirectories as well). You will most often put a dot (meaning current directory) here.
• -name [file_mask]… search files by name (if you use wildcards, be careful to escape them with a backslash - we want to have find command expand the wildcard, not the shell that is running find)
• xargs - constructs the arguments list and executes the command
• -I [repl_symbol]… use something as a replacement placeholder. Using percentage sign (%) seems to work ok.
• [command]… specify a command you want to run on found files. E.g. cp % destdir will copy found file (if % is used as replacement symbol) to the destination directory.

Example
I used this little trick to find all .ko files located in various subdirectories of the current directory and copy them to a specific directory:
find . -name \*.ko | xargs -I % cp % modules/