pi@raspberrypi:~/Desktop $ sudo ls -al
total 16
d-wx--x--x 3 pi pi 4096 Jan 12 11:30 .
drwxr-xr-x 21 pi pi 4096 Jan 12 11:28 ..
-rw-r--r-- 1 pi pi 82 Jan 11 16:13 cmd.txt
drwxr-xr-x 6 pi pi 4096 Jan 12 11:30 openvibe-2.0.0-src
pi@raspberrypi:~/Desktop $ ls
ls: cannot open directory '.': Permission denied