perl -pni.bak -e "s/1 (\w{1,2}v\w{1,2})/2 $1/" filename

##</code><code>##

c:\> for %f in (*.html) do perl -pni.bak -e "s/1 (\w{1,2}v\w{1,2})/2 $1/" %f

##</code><code>##

perl -pi.bak -e 's/\b(\w{1,2}v\w{1,2})\b/g<a href="$1.html">$1<\/a>/" filename