UNIX Tools - examples

Here are a few examples you'll probably find useful at some point. Counting the number of lines of a C project
$ wc -l `find -name "*.[ch]"|xargs`
Execute a command on a directory and all its subdirectories
$ find "path" -exec "command" {} ;
Deleting all the files not accessed for 1 day in the current directory and all its subdirectories
$ find .