/usr/share/doc/netcat-openbsd/examples/ncp is in netcat-openbsd 1.105-7.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #! /bin/sh
## Like "rcp" but uses netcat on a high port.
## do "ncp targetfile" on the RECEIVING machine
## then do "ncp sourcefile receivinghost" on the SENDING machine
## if invoked as "nzp" instead, compresses transit data.
## pick your own personal favorite port, which will be used on both ends.
## You should probably change this for your own uses.
MYPORT=23456
## if "nc" isn't systemwide or in your PATH, add the right place
# PATH=${HOME}:${PATH} ; export PATH
test "$3" && echo "too many args" && exit 1
test ! "$1" && echo "no args?" && exit 1
me=`echo $0 | sed 's+.*/++'`
test "$me" = "nzp" && echo '[compressed mode]'
# if second arg, it's a host to send an [extant] file to.
if test "$2" ; then
  test ! -f "$1" && echo "can't find $1" && exit 1
  if test "$me" = "nzp" ; then
    compress -c < "$1" | nc -v -w 2 $2 $MYPORT && exit 0
  else
    nc -v -w 2 $2 $MYPORT < "$1" && exit 0
  fi
  echo "transfer FAILED!"
  exit 1
fi
# fall here for receiver.  Ask before trashing existing files
if test -f "$1" ; then
  echo -n "Overwrite $1? "
  read aa
  test ! "$aa" = "y" && echo "[punted!]" && exit 1
fi
# 30 seconds oughta be pleeeeenty of time, but change if you want.
if test "$me" = "nzp" ; then
  nc -v -w 30 -p $MYPORT -l < /dev/null | uncompress -c > "$1" && exit 0
else
  nc -v -w 30 -p $MYPORT -l < /dev/null > "$1" && exit 0
fi
echo "transfer FAILED!"
# clean up, since even if the transfer failed, $1 is already trashed
rm -f "$1"
exit 1
 |