#!/bin/sh
set -e
# see parent-process Y-
y=''
g=''
x=''

# notes
#"$@" <"$f"
 #no quotes?
# end

Die() {
 exit $1
}
usage() {
 printf >&2 '%s\n' 'usage: Y FILE [CMD...]'\
 'stream-out [ nil or CMD ] <FILE'
 Die 1
}

quote(){ xe -Q "$@";}

if [ "$(eval echo $(quote "'| "\"))" != "'| "\" ];then
 printf >&2 '%s\n' 'Y: shell satisfies [ "$(eval echo "$(quote "'\''| "\")")" != "'\''| "\" ]'\
 'to procede with use, look inside quote(){...}'
 Die 1
fi

case $Y in
[0-9]*)
 y=$(echo "$Y" |grep -o "^[0-9]*")
 Y=$(echo "$Y" |sed "s/^[0-9]*//")
 ;;
esac
case $Y in
''|u) 
if [ -z "${y:+s}" ];then
[ $# -lt 1 ]&& usage
 f="$1"
 shift 1
fi
 ;;
*[^nud]*)
 printf >&2 '%s\n' 'Y: malformed $Y'
 Die 1
 ;;
*)
 y=0
 ;;
esac

case "$Y" in
*u*)
 x="$@"
 ;;
*)
 x=$(quote "$@")
 [ "$x" = "''" ]&& x=""
 ;;
esac

case $Y in
*d*)
 printf '%s\n' "$x"
 ;;
*n*)
 eval "$x"
 ;;
*)
 if [ -z "${y:+s}" ];then
  <"$f" eval "$x"
 else
  <&$y eval "$x"
 fi
 ;;
esac