snort no detect any attack

[bz Os via Snort-sigs <snort-sigs () lists snort org>]

i am using snort ++ ,i want to evaluate snort by darpa dataset as output i
had any detection of attack :the command that i taped is :
snort -c snort.lua -R snort3-community.rules -A unified2 -r
outside_Darpa.tcpdump - l /var/snort/log

how i can detect attack ,?

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