pcattcp -h

PCAUSA Test TCP Utility V2.01.01.13 (IPv4/IPv6)
       Usage: pcattcp -t [-4|-6] [-options] host [ < in ]
       pcattcp -r [-4|-6] [-options > out]
Common options:
   -4 use IPv4 (default)
   -6 use IPv6
   -l ## length of bufs read from or written to network (default 8192)
   -u use UDP instead of TCP
   -p ## port number to send to or listen at (default 5001)
            Can specify multiple sequential ports two ways:
            -p #first-#last
            -p #first+#additional
   -s toggle sinkmode (enabled by default)
            sinkmode enabled:
               -t: source (transmit) fabricated pattern
               -r: sink (discard) all received data
            sinkmode disabled:
               -t: reads data to be transmitted from stdin
               -r: writes received data to stdout
   -A align the start of buffers to this modulus (default 16384)
   -O start buffers at this offset from the modulus (default 0)
   -v verbose: print more statistics
   -d set SO_DEBUG socket option
   -b ## set socket buffer size (if supported)
   -f X format for rate: k,K = kilo{bit,byte}; m,M = mega; g,G = giga
   -c -t: send continuously
            -r: accept multiple connections sequentially
   -a bind to local host interface IP address
Options specific to -t:
   -n ## number of source bufs written to network (default 2048)
   -D don‘t buffer TCP writes (sets TCP_NODELAY socket option)
   -w ## milliseconds of delay before each write (default 0)
   -R ## desired transmit data rate in bytes/second
Options specific to -r:
   -M concurrent TCP/UDP multithreaded receiver
   -B for -s, only output full blocks as specified by -l (for TAR)
   -T "touch": access each byte as it‘s read