# 1: cp /bin/ls chmod.01 cp /bin/chmod chmod.01 ./chmod.01 700 file # 2: /bin/busybox chmod 0700 /bin/chmod # 3: setfacl --set u::rwx,g::---,o::--- /bin/chmod Tool: who Find last reboot time who -b Detect a user sudo-su'd into the current shell [[ $(who ...