perl -pi -e 'substr($_,589,35) =~ s/(\s*)(\w+)*/$2$1/ if /^(.{589})(\s{1,34})/' file.txt

##</code><code>##

perl -pi -e 'substr($_,589,35) =~ s/(0*)(\w+)*/$2($?{ ' ' x length($1) })/ if /^(.{589})(0{1,34})/' file.txt

##</code><code>##

perl -pi -e 'substr($_,589,35) =~ s/(0*)(\w+)*/$2($?{ " " x length($1) })/ if /^(.{589})(0{1,34})/' file.txt