ussop@Roronoa-Zoro:~$ sudo lsof /dev/video*
[sudo] password for ussop: 
lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs
      Output information may be incomplete.
COMMAND    PID  USER   FD   TYPE DEVICE SIZE/OFF  NODE NAME
skypeforl 1955 ussop  mem    CHR   81,0          17939 /dev/video0
skypeforl 1955 ussop   94u   CHR   81,0      0t0 17939 /dev/video0