Define the sort key with the start and stop character position of the key:

sort -nk1.6,1.8 file


See your friendly sort manpages.

Sort lines based on a variable-width number at a fixed position
Host OS: Windows 7 Guest OS: Ubuntu 11.04

Say if I won't need to work on the guest OS for 1 hour, while having a lot of programs running and don't want to close them. What is the best way to pause my work on the guest OS? Ubuntu has suspend and hibernate. I found that hibernate won't work as it always fails to boot up after hibernate. For suspend, should I couple it with Virtualbox pause to release the host OS resources. Would this cause any issue once resume the work? Since I found sometimes the guest OS becomes slower resume from pause VM.
