#!/bin/ksh
# 
#
function KeyVal {
	typeset IN_FILE=${1}
	typeset KEYWORD=${2}
	
	typeset key_value=`dd if=${IN_FILE} ibs=2880 count=20 obs=80 cbs=80 conv=unblock 2>>/dev/null |
		$(whence egrep) -e "^${KEYWORD}" |
  		cut -b9-80|  awk '{
      				init_sub=index($0,"=")
      				init_quote=index($0,"'\''")

       				if (init_quote == 0) 
					init_quote=init_sub
       				else
      					end_quote=index(substr($0,init_quote+1),"'\''")
			

			        if (end_quote == 0) 
					end_quote=80

			        len_sub=end_quote-init_quote
	
      				print substr($0,init_quote+1)}' |
      				awk '{print $1}' |
      				sed -e s/\'//g`

				echo ${key_value}
}
#
echo "images " >> corr_$$.cl
#
# Next means the the script works on all files of the current dir
if [[ $# -le 0 || $# -gt 1 ]] then
	print " Usage $0: <file_list> "
	exit 0
fi
#
#
#
# check if the files exists
#
	if [[ ! -r ${1} ]] then
		print " file ${1} doesn't exist"
		exit 0
	fi
#
	cat $1 | \
	while read f; do
#
	if [[ ! -r ${f} ]] then
		echo " Failed with file: " ${f} 
		continue	
	fi
#
#
typeset filter=""
#
filter=`KeyVal ${f}  "HIERARCH ESO INS FILT NAME"`
#
	if [[ -z ${filter} ]] then
	filter="__UNKNWOWN__"
	fi
#
#
#

#  header update
{
	echo 'hedit '${f}[0]' FILTER   '${filter}' add+ ver- show+ up+ del-'
} >> corr_$$.cl 
#
done
#
echo
echo " the Iraf script to update headers is:"
echo "\n\t\t" corr_$$.cl
echo "\n"
exit 0
#