#bash #openN open the N-th line of piped input

openN

#!/bin/bash

[[ ${COLORS_SOURCE} ]] && source ${COLORS_SOURCE}

EXEC_CMD=

SCRIPT=$(basename $0)
_BSCRIPT=${_BLD}${SCRIPT}${_RST_}
function _help()
{
	echo -e
	echo -e "${_BSCRIPT} - open the N-th line from stream"
	echo -e
	echo -e "${_BU}Synopsis${_RST_}"
	echo -e
	echo -e "  ${_BSCRIPT}"
	echo -e "  ${_BSCRIPT} --help"
	echo -e "    Display this help"
	echo -e
	echo -e "  ${_UND}cmd${_RST_} | ${_BSCRIPT}"
	echo -e "  ${_BSCRIPT} < ${_UND}file${_RST_}"
	echo -e "    Prefix line number to each line (equivalent of \`cat -n\`)"
	echo -e
	echo -e "  ${_UND}cmd${_RST_} | ${_BSCRIPT} [${_UND}option${_RST_}] ${_UND}N${_RST_}"
	echo -e "  ${_BSCRIPT} [${_UND}option${_RST_}] ${_UND}N${_RST_} < ${_UND}file${_RST_}"
	echo -e "    Opens the ${_UND}N${_RST_}-th line of input"
	echo -e
	echo -e "${_BU}Supported options${_RST_}"
	echo -e
	echo -e "  -c, --exec ${_UND}EXEC_CMD${_RST_}:"
	echo -e "    Specify the command to be executed on ITEM"
	echo -e
	echo -e "${_BLD}Author:${_RST_} ${_UND}leesei@gmail.com${_RST_}      ${_BLD}Licence:${_RST_} MIT"
	echo -e "${_UND}https://gist.github.com/leesei/7044050${_RST_}"
	echo -e

	# error messages
	if [[ $# -ne 0 ]]; then
		echo  # seperator
		while [ -n "$*" ]; do
			echo -e ${RED}"$1"${_RST_}
			shift
		done
		echo
	fi
}

if [ "$(tty)" != 'not a tty' ]; then
	_help
	exit
fi

case $(uname) in
	# choose open command
	Darwin) OPEN_CMD=open ;;
	Linux) OPEN_CMD=xdg-open ;; # assuming X is present
	CYGWIN*) OPEN_CMD=cygstart ;;
	*) echo "Unknown OS"; exit 1 ;;
esac

# Parse arguments
TEMP=$(getopt -n ${SCRIPT} -o c:h \
--long exec,\
help \
-- "$@")

if [ $? -ne 0 ]; then
	_help "getopt error"
	exit 2
fi

eval set -- "$TEMP"
while true; do
	case $1 in
	-c|--exec)
		EXEC_CMD="$2"; shift;
		shift; continue
		;;
	-h|--help)
		_help
		exit 0
		;;
	--)
		# no more arguments to parse
		break
		;;
	*)
		printf "Unknown option %s\n" "$1"
		exit 1
		;;
	esac
done

# Remove the switches (including the added "--") we parsed above
shift `expr $OPTIND`

if [ $# -eq 0 ]; then
	cat -n -
	exit 0
fi

# select the n-th line
ITEM=$(cat - | sed "$1q;d")
if [[ ${EXEC_CMD} ]]; then
	echo "Exec \"${EXEC_CMD} ${ITEM}\"..."
	${EXEC_CMD} "${ITEM}"
else
	echo "Opening \"${ITEM}\"..."
	# quite the output
	${OPEN_CMD} "${ITEM}" > /dev/null 2>&1
fi