replace worded digits closest to edges of line

day1.sh

@@ -12,13 +12,37 @@ num[9]=nine
 declare -a val # make array to hold values
 cat $1 | while read l; do # read standard input
 	((i++)) # increment index
-	echo before transform: $l
-	for n in {1..9}; do
-		l=`echo $l | sed "s/${num[$n]}/$n/g"`
+
+	li="$l"
+	for ni in {1..9}; do # ascend through worded digits
+		li=`echo $li | sed "s/${num[$ni]}/$ni/g"`
 	done
-	echo after transform: $l
-	first=`echo $l | grep -E -o '^[a-z]*?[0-9]' | grep -o [0-9]`
-	last=`echo $l | grep -E -o '[0-9][a-z]*?$' | grep -o [0-9]` # extract the first and last number from the line
+
+	ld="$l"
+	for nd in {9..1}; do # ... and descend
+		ld=`echo $ld | sed "s/${num[$nd]}/$nd/g"`
+	done
+
+	lifd=`echo $li | grep -E -o '^[a-z]*?[0-9]'` # select distance to first match, ascending
+	ldfd=`echo $ld | grep -E -o '^[a-z]*?[0-9]'` # then descending
+
+	if [[ ${#ldfd} -lt ${#lifd} ]]; then # compare first match's distance
+		bf=$ld
+	else
+		bf=$li
+	fi
+
+	ldld=`echo $ld | grep -E -o '[0-9][a-z]*?$'` # select distance to last match, ascending
+	lild=`echo $li | grep -E -o '[0-9][a-z]*?$'` # then descending
+
+	if [[ ${#ldld} -lt ${#lild} ]]; then # compare last match's distance
+		bl=$ld
+	else
+		bl=$li
+	fi
+
+	first=`echo $bf | grep -E -o '^[a-z]*?[0-9]' | grep -o [0-9]`
+	last=`echo $bl | grep -E -o '[0-9][a-z]*?$' | grep -o [0-9]` # extract the first and last number from the line
 	val[$i]=`echo "($first*10)+$last" | bc` # assign combined number to the array at current index
 	echo ${val[$i]}
 	echo -n total: