Handle SSH differences across platforms with a preloader

alias fgrep='~/.shell/bin/grep-auto-exclude fgrep -n'

alias egrep='~/.shell/bin/grep-auto-exclude egrep -n'

# special SSH

alias ssh='~/.ssh/ssh'

## Common miss-spellings

## =====================

#!/bin/sh

set -eu

ssh_version() {

	eval `ssh -V 2>&1 | sed -n \

		's/OpenSSH_\([0-9]\+\)\.\([0-9]\+\).*/SSH_MAJOR="\1" SSH_MINOR="\2"/p'`

}

platform() {

	case `uname` in

		Linux*) PLATFORM=linux ;;

		CYGWIN*) PLATFORM=windows ;;

		Darwin*) PLATFORM=darwin ;;

		*) echo >&2 "Unrecognised platform: `uname`"; exit 2 ;;

	esac

}

rule_unix_sockets() {

	# Windows has no unix sockets so disable shared connections

	# (Control* settings)

	if [ $PLATFORM = windows ]; then

		echo '/^\s*Control.*/d;'

	fi

}

rule_canonisation() {

	# OpenSSH < 6.6 does not have name canonisation

	# (Canonical* settings)

	if [ $SSH_MAJOR -gt 6 ]; then return; fi

	if [ $SSH_MAJOR -lt 6 ] || [ $SSH_MINOR -lt 6 ]; then

		echo '/Canonical/d;'

	fi

}

make_config() {

	platform && ssh_version

	CONFIG=`mktemp -p ~/.ssh/ .config.XXXXXX`

	trap 'rm "$CONFIG"' EXIT

	cat ~/.ssh/config ~/.ssh/config.local 2>/dev/null |

		sed >"$CONFIG" "

			`rule_unix_sockets`

			`rule_canonisation`

		"

}

case " $*" in

	*' -F'*) command ssh "$@" ;;

	*)

		make_config

		command ssh -F $CONFIG "$@"

		;;

esac