scp compliant copy without encryption using netcat

nccp.sh

#!/bin/bash

echo "Arguments: "
echo "${@}"

set -x #explain steps for debug purposes
set -e #exit when any command executed fails unexpectedly

IFS=$'\n'

#ensure our background tasks get stopped too
#trap "trap - SIGTERM && kill -- -$$" SIGINT SIGTERM EXIT
trap '[ -n "$(jobs -r -p)" ] && kill $(jobs -r -p) 2>/dev/null' SIGINT SIGTERM EXIT

PORT="2020"
TIMEOUT="5" #timeout in s
HOSTNAME="$(hostname)" #hostname used for identifying this PC in the network
SSH="ssh" #ssh command for initiating connection
#SSH_PRECOMMAND="[ -z $(command -v nc) ] && exit 1; "

isremotehost() {
	HOST="$1"
	[[ "$HOST" != *':'* ]] && return 1
	[[ "$HOST" == "/"* || "$HOST" == "./"* ]] && return 1
	return 0
}
islocalfile() {
	isremotehost "$@" || return 0 && return 1
}

[ $# -gt 2 ] && {
	SOURCE="$1"
	TARGET="${@: -1}"
	$0 "$SOURCE" "$TARGET"
	shift
	$0 "$@"
	exit $?
}

SOURCE="$1"
TARGET="$2"
islocalfile "$TARGET" && [ -f "$TARGET" ] && echo "Automatically overwriting $TARGET"

islocalfile "$SOURCE" && islocalfile "$TARGET" && {
	echo "Both files are local, copying normally"
	cp -f "$SOURCE" "$TARGET"
	exit $?
}

SOURCE_FILESPEC="$SOURCE"
isremotehost "$SOURCE" && {
	SOURCE_FILESPEC="${SOURCE##*:}"
	SOURCE_HOST="${SOURCE%:*}"
}
TARGET_FILESPEC="$TARGET"
isremotehost "$TARGET" && {
	TARGET_FILESPEC="${TARGET##*:}"
	[ -z "$TARGET_FILESPEC" ] && TARGET_FILESPEC="."
	TARGET_HOST="${TARGET%:*}"
}

SEND_HOST="$HOSTNAME"
isremotehost "$SOURCE" && {
	SEND_HOST="${SOURCE_HOST##*@}"
	SEND_HOST_SSH="$SOURCE_HOST"
}
RECV_HOST="$HOSTNAME"
isremotehost "$TARGET" && {
	RECV_HOST="${TARGET_HOST##*@}"
	RECV_HOST_SSH="$TARGET_HOST"
}

NC_TAR_SOURCE=("cd" "$(dirname "$SOURCE_FILESPEC")" "&&" "tar" "cf" "-" "$(basename "$SOURCE_FILESPEC")")
NC_UNTAR_TARGET=("tar" "xfv" "-" "-C" "$(dirname "$TARGET_FILESPEC")")
declare -p NC_TAR_SOURCE
declare -p NC_UNTAR_TARGET
NC_SEND=("${NC_TAR_SOURCE[@]}" "|" "nc" "-w" "$TIMEOUT" "$RECV_HOST" "$PORT")
NC_RECV=("nc" "-l" "-p" "$PORT" "|" "${NC_UNTAR_TARGET[@]}")
declare -p NC_SEND
declare -p NC_RECV

if [ "$RECV_HOST" = "$HOSTNAME" ]; then
	eval "${NC_RECV[@]}" "&"
else
	$SSH "$RECV_HOST_SSH" "${NC_RECV[@]}" &
fi

sleep 5

if [ "$SEND_HOST" = "$HOSTNAME" ]; then
	eval "${NC_SEND[@]}" "&"
else
	$SSH "$SEND_HOST_SSH" "${NC_SEND[@]}" &
fi

wait

NCCP

A scp command line compliant copy tool for copying files without encryption using netcat and initiating the connection using ssh.

Install

Download the script and run it.
You can save it into your home folder and add

alias nccp="bash ~/nccp.sh"

to your .bash_aliases for easy access.