How many times have we been working hard on an issue, searching forums, blogposts, stack overflow, etc, and come across a proposed solution that says “just paste this into your terminal”? In the heat of the moment it is easy to forget that this situation deserves caution. The problem is that it is easy to sneak extra commands into those cut/copy/pastes thusly:

example 1: git clone /dev/null; clear; echo -n "Hello ";whoami|tr -d '\n';echo -e '!\nThat was a bad idea. Don'"'"'t copy code from websites you don'"'"'t trust!
Here'"'"'s the first line of your /etc/passwd: ';head -n1 /etc/passwd
git clone git://git.kernel.org/pub/scm/utils/kup/kup.git

example 2: echo "not evil"

Try them out by copying and pasting into bash like terminal window, I promise they’re 100% benign. Credits in source html.