tshark: cannot save captured file to a file

Cannot capture packet in uaual user, while cannot save file in privilege mode
tshark -i 1 -a duration:10 -w x.pcap

tshark: Lua: Error during loading:
 [string "/usr/share/wireshark/init.lua"]:46: dofile has been disabled due to running Wireshark as superuser. See http://wiki.wireshark.org/CaptureSetup/CapturePrivileges for help in running Wireshark as an unprivileged user.
Running as user "root" and group "root". This could be dangerous.
Capturing on 'wlan0'
tshark: The file to which the capture would be saved ("x.pcap") could not be opened: Permission denied.

http://anonscm.debian.org/viewvc/collab-maint/ext-maint/wireshark/trunk/debian/README.Debian?view=markup

groupadd wireshark
useradd -G wireshark <username>
usermod -a -G wireshark <username>

Always remember to reboot or logout to have the change take effect!!!

https://wiki.wireshark.org/CaptureSetup/CapturePrivileges

setcap 'CAP_NET_RAW+eip CAP_NET_ADMIN+eip' /usr/bin/dumpcap