#! /bin/sh

# ul-grep -- underline grep 
# $Id: ul-grep,v 1.1 1998/09/06 23:15:17 cdua Exp cdua $
# Carlos Duarte, 980710

#trap -- 'rm -f /tmp/xpto' EXIT SIGINT

UNDER="^"
SPACE=" "

USAGE="\
usage: $0 [-h] [-s space] [-u underline] pattern [input-files...]

  -h      this help
  -s c    use c, as the space character (default: '$SPACE')
  -u c    use c, as the underliner char (default: '$UNDER')
  -p      output only lines where pattern lives
  -1 .. -9
	  only underlines #ed pattern 

eg: 
      $0 -p \$USER /etc/passwd
"

while : ; do
	case x"$1" in 
	x-h)	echo "$USAGE"; exit 1 ;;
	x-s)	shift; SPACE="$1" ;;
	x-u)	shift; UNDER="$1" ;;
	x-p)	PAT_NOT_FOUND='d' ;; 
	x-[1-9])
		G=`echo x$1|cut -c3` ;; 
	x-h)	echo "$USAGE"; exit 1 ;;
	x--)	shift; break ;;
	x-?)	echo "invalid option -- `echo $1|cut -c2-`"
		echo "$USAGE"; exit 1 ;;
	*)	break ;;
	esac
	shift
done

# if _must_ accept on extra argument after options
if test $# -eq 0; then echo "$USAGE"; exit 1; fi

PAT="`echo \"$1\" | sed 's:/:\\\\/:g'`"
shift
sed "
h
s/$PAT/\\
&\\
/${G-g}
t done
${PAT_NOT_FOUND-b}
:done
s/[^
]/$SPACE/g
:again
/\n\n/b ok
s/\n./$UNDER\\
/
b again
:ok
s/\n\n//
/\n/b again
x
p
x" $*

#exit 0
exit