While installing software in linux (kali 2.0) you may get following error it could be your software list is not up to date:
E: Unable to locate package
Now if you run command apt-get upgrade you will end up with following output:
Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Now you will not be to install the software until you update your list. For apt-get upgrade to work you have to go to the file sources.list and get the url from official website of your OS and add it to that file