Can i use pupular applications names in my game?

Am wondering if i can use the exact name of a famous tool in Linux in my game.
For example, there is a command in Linux called

ifconfig

Can i use the same name, or should i come up with a new name? Is there copyrights on such stuff ?

In addition to Mintonne’s response, most of these Linux tools are not trademarked, and are rarely the first tools to use those names as they were originally implemented on Unix and the Linux tools are actually reimplementations.