CPS 393 Lecture Notes - Lecture 10: Unix Security, File System Permissions, Shell Script
4 Aug 2016
School
Department
Course
Professor
Document Summary
Child 1 # another unix shell script myprog # an executable c program. File permissions: there are 3 levels of security. Within each of the above levels, there are separate read, write and execute permissions: How to set files or directories permission? chmod file(s) Permissions (turned on is 1, off is 0) 2^2 = 4 permissions of public notice chmod 644 public_notice. Or chmod u=rw, go=r since g = o = r chmod u=rw, go=(personal) // you are setting user to read + write. // but you"re setting group and other to be unchanged. // go = *blank* means to have them turn off. Not have go = *nothing* leaves go permissions as they were previously (this is bad!!! don"t be dumb don"t do this!!) chmod ug=r, o=(important) chmod g+w public_notice. // user and other is not mentioned in this cmd so whatever permissions that were before remain unchanged. Turn off execute permission for show_balance: chmod o-x show_balance.
