whenever i attempt to install aircrack-ng in terminal i get the following error "Package aircrack-ng is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it: iw

E: Package 'aircrack-ng' has no installation candidate"

im new to ubuntu and so have no idea what to do :P any suggestions? and if so try your best to do it in english terms :)