ssh-host

#!/usr/bin/env bash
#
#  Synopsis:
#	ssh into a host derived from symbolic link to ssh-host
#  Usage:
#	ln -s /usr/local/jmscott/bin/ssh-host bin/skytel
#	bin/skytel [-l host_user] [-e <remote exec>]
#  Description:
#	Login to a host, deriving the host name from the name
#	of the script.  This script is never invoked directly.
#	Instead, a link to this script is made, where the link 
#	file name is the remote ssh host, and the linked
#	script is invoked from the command.
#
#	Prior to invoking ssh the remote host name is set as the
#	"title" of the terminal by sending the ANSI escape sequence.
#	This might fail on non ANSI complient terminals, like sunterm.
#  Options:
#	-l  login_user
#	-n  no strict host checking
#	-p  port
#	-h  remote_host
#	-X  X11 forwarding
#	-e  remote exec argv
#	-t  title of terminal
#  Blame:
#	https://github.com/jmscott
#  See:
#	xtitle in repo https://github.com/jmscott/work
#	GNU or BSD hostname
#  Note:
#	Would be nice to reset to previous value of title by somehow querying
#	the terminal.
#
#	Add a --help option, dear god.
#
PROG=$(basename $0)
HOST=$PROG
SSH_ARGS=''
tty >/dev/null
IS_TTY=$?

LOGIN_USER=$USER

#
#  Reset the title to this value after ssh exits.
#  Would be nice to query the xterm for the current title value.
#
LOCAL_TITLE="$USER@$(hostname | sed 's/\..*$//')"

log()
{
	#
	#  Log to standard error, in case redirecting standard output
	#  of remote shell exec
	#
	echo "$PROG: $@" >&2
}

die()
{
	echo "ERROR: $PROG: $@" >&2
	exit 1
}

#
#  Process the command arguments.
#
#	-l  login_user
#	-n  no strict host checking
#	-p  port
#	-h  remote_host
#	-X  X11 forwarding
#	-e  remote exec
#	-t  title of terminal
#
while [ -n "$1" ];  do
	case "$1" in
	-p|--port)
		shift
		case "$1" in
		'')
			die "missing port number for option -p"
			;;
		[1-9]*)
			log "connecting on port #$1"
			SSH_ARGS="$SSH_ARGS -p $1"
			;;
		*)
			die "funny port number for option -p: $1"
			;;
		esac
		;;
	-n|--no-strict)
		log "no strict host key check, ignore possible warning"
		SSH_ARGS="$SSH_ARGS \
			-o UserKnownHostsFile=/dev/null \
			-o StrictHostKeyChecking=no"
		;;
	-l|--login)
		shift
		case "$1" in
		'')
			die "-l option missing user login name"
			;;
		*)
			LOGIN_USER=$1
			log "logging in as user $LOGIN_USER"
			SSH_ARGS="$SSH_ARGS -l $LOGIN_USER"
			;;
		esac
		;;
	-h|--host)
		shift
		case "$1" in
		'')
			die "-h missing host name"
			;;
		[a-zA-Z0-9]*)
			log "remote host is $1"
			;;
		*)
			die "option -h: unexpected host name: $1"
		esac
		;;
	-X|--X11-forward)
		log "X11 forwarding enabled"
		SSH_ARGS="$SSH_ARGS -X"
		;;
	#
	#  Remain arguments are remote ssh execution.
	#
	-e|--exec)
		shift
		#
		#
		#
		while [ -n "$1" ];  do
			SSH_REMOTE_EXEC="$SSH_REMOTE_EXEC $1"
			shift
		done
		log "remote ssh exec:$SSH_REMOTE_EXEC"
		break
		;;
	-t)
		shift
		TITLE="$1"
		;;
	*)
		die "unknown option: $1"
		;;
	esac
	shift
done

TITLE=${TITLE:="$LOGIN_USER@$HOST"}

#
#  Write directly to the tty in case we are redirecting the
#  output of a remote execution.
#
test $IS_TTY = 0 && xtitle "$TITLE" >/dev/tty
ssh $SSH_ARGS $HOST $SSH_REMOTE_EXEC

#
#  Reset the terminal title.
#  Would be nice to reset to previous value by querying the terminal.
#
test $IS_TTY = 0 && xtitle "$LOCAL_TITLE"