If you want to copy file on Unix system you can use simple, built-in command
file_2 run following command.
cp file_1 file_2
Copying multiple files in directory works the same way.
cp file_1 file_2 directory_1
Useful flags for command
-n- don't overwrite an existing file
-f- if destination file can't be opened, delete it and create new file
-p- preserve file modification time, access time...
-v- verbose output (print copied files to stdout)
Note that this only works with files. View how to copy directories here.