You can dump memory on Linux just by doing:

cat /proc/kcore > dump
[download]

That will put a raw dump of everything in memory into the file dump.

However you will not be able to recover plain ASCII text of your script from such a dump because it is simply not kept in memory. Nor is a file decriptor help open for it (as in the lsof example you quote). A file descriptor would just let you access the disk so is fairly pointless in this case anyway.

I would suggest data recovery on your disk. Spinrite may do the trick if your crashed disk will still spin up.