ishkur@linuxbox:~$ snort --help
snort: invalid option -- -

   ,,_     -*> Snort! <*-
  o"  )~   Version 2.3.3 (Build 14)
   ''''    By Martin Roesch & The Snort Team: http://www.snort.org/team.html
           (C) Copyright 1998-2004 Sourcefire Inc., et al.

USAGE: snort [-options] <filter options>
Options:
        -A         Set alert mode: fast, full, console, or none  (alert file alerts only)
                   "unsock" enables UNIX socket logging (experimental).
        -b         Log packets in tcpdump format (much faster!)
        -c <rules> Use Rules File <rules>
        -C         Print out payloads with character data only (no hex)
        -d         Dump the Application Layer
        -D         Run Snort in background (daemon) mode
        -e         Display the second layer header info
        -f         Turn off fflush() calls after binary log writes
        -F <bpf>   Read BPF filters from file <bpf>
        -g <gname> Run snort gid as <gname> group (or gid) after initialization
        -h <hn>    Home network = <hn>
        -i <if>    Listen on interface <if>
        -I         Add Interface name to alert output
        -k <mode>  Checksum mode (all,noip,notcp,noudp,noicmp,none)
        -l <ld>    Log to directory <ld>
        -L <file>  Log to this tcpdump file
        -m <umask> Set umask = <umask>
        -n <cnt>   Exit after receiving <cnt> packets
        -N         Turn off logging (alerts still work)
        -o         Change the rule testing order to Pass|Alert|Log
        -O         Obfuscate the logged IP addresses
        -p         Disable promiscuous mode sniffing
        -P <snap>  Set explicit snaplen of packet (default: 1514)
        -q         Quiet. Don't show banner and status report
        -r <tf>    Read and process tcpdump file <tf>
        -R <id>    Include 'id' in snort_intf<id>.pid file name
        -s         Log alert messages to syslog
        -S <n=v>   Set rules file variable n equal to value v
        -t <dir>   Chroots process to <dir> after initialization
        -T         Test and report on the current Snort configuration
        -u <uname> Run snort uid as <uname> user (or uid) after initialization
        -U         Use UTC for timestamps
        -v         Be verbose
        -V         Show version number
        -w         Dump 802.11 management and control frames
        -X         Dump the raw packet data starting at the link layer
        -y         Include year in timestamp in the alert and log files
        -z         Set assurance mode, match on established sesions (for TCP)
        -?         Show this information
<Filter Options> are standard BPF options, as seen in TCPDump
ishkur@linuxbox:~$