Shell Programming and Scripting

#!/bin/sh
echo "UK currency sign is £ as in £100.25p." > /tmp/pound.txt
read pound < /tmp/pound.txt
length=$[ ( ${#pound} - 1 ) ]
newtext=""
for subscript in $( seq 0 $length )
do
	if [ "${pound:$subscript:1}" == "£" ]
	then
		newtext="$newtext#"
	else
		newtext="$newtext${pound:$subscript:1}"
	fi
done
echo ""
echo "File _pound_ unchanged..."
echo "$pound"
echo ""
echo "Variable _newtext_ showing # sign in its place..."
echo "$newtext"
echo ""

Last login: Thu Dec 12 07:43:53 on ttys000
AMIGA:barrywalker~> chmod 775 pound.sh
AMIGA:barrywalker~> ./pound.sh

File _pound_ unchanged...
UK currency sign is £ as in £100.25p.

Variable _newtext_ showing # sign in its place...
UK currency sign is # as in #100.25p.

AMIGA:barrywalker~> _