remove_html() { sed -e 's/<[^>]*>//g' ;}
print_lines_from_to() { sed -n '5,10p' ;}
remove_last_line() { sed '$d' ;}
remove_leading_and_trailing_whitespace() { sed -e 's/^ [\t]*//g' -e 's/[ \t]*$//g'; }
insert_space_between_characters() { sed 's/./& /g' ;}