How to replace substring in file, using SED editor,
with parameters passed to SED. (environment variables)

!/bin/sh

SRCFILE=/home/path/srcfile
DSTFILE=/home/path/dstfile

FIND='&quote;'
REPL='"'

sed -e 's/'"$FIND"'/'"$REPL"'/g' $SRCFILE > $DSTFILE