Se suas strings estiverem em um arquivo chamado file
:
$ sed 's|</td><td><a href="javascript:[^>]*">|;|g' file
Central and Western;Kwun Lung Lau
Central and Western;The Merton
Eastern;Fung Wah Estate
Wong Tai Sin;Tsz Oi Court
Se a sua string estiver em uma variável do shell chamada s
:
$ echo "$s"
Central and Western</td><td><a href="javascript:pop1('major-housing-estate/30006.html');" title="Kwun Lung Lau">Kwun Lung Lau
$ echo "$s" | sed 's|</td><td><a href="javascript:[^>]*">|;|g'
Central and Western;Kwun Lung Lau