Yesterday I was approached with a interesting problem. This guy simply couldn’t write the ‘d’ char anymore. To see if it was software or hardware related, he was about to add a new user to try with. He was confused how to add a new user though, since adduser, useradd and /etc/passwd all have the ‘d’ char in it.
There’s a couple more or less interesting ways to solve this.
And the little more interesting way…
What this does is actually pretty simple. We print a ‘a’, two ‘d’ using the chr() function, ‘user’, and since we wrapped it all in $(), it executes in the shell, and voilá!