Rather than reposting data that is already on the net, I recommend checking out some of the posts at http://stackoverflow.com/questions/12522388/sed-awk-match-a-pattern-and-return-everything-between-the-end-of-the-pattern-a

In addition you may be able to find some other scripts that can help at http://www.commandlinefu.com

I have not used NS2, but I will try my best to help. If the executable is stored in a folder that is displayed in the output of "echo $PATH" then the app should be capable of launching by just typing the name. Please make sure that the app is executable and that your path is located in your path environmental variable.

Does the app run when you attempt to execute it directly from the containing folder?

Nearly any distro will work for your needs except for gaming, you need to be aware that windows games will not work in other operating systems. There are some software layer libraries like wine, crossover games, etc.. which will allow some games to be played, but as it is noon-native there will be bugs and some programs just won't work.

As a starter you shoud checkout linux mint or ubuntu as they are user friendly and have large software repos, you can also test them from a CD to test the interface. When running any OS from a disk the experience will be slow because all data must be cached into ram, so they speed will differ on disk compared to being on the HDD.

As for relaibility, stability and security those are the best reason to try linux, the large community or developers and active contributors help to ensure that most bugs are discovered and resolved quickly.

I am hoping that your problem is with signal interference as it would show itself differently in linux than in windows because some manufacturer supplied drivers are instructed to ignore some types of errors. However, if the problem started with a kernel update then it may be a sign of a regression in the drivers for your wifi card to which I highly recommend plugging the device into the wired network and reporting the problem to ubuntu so see that they say since they also have kernel engineers and can work on a solution.

I found some references to someone testing gang scheduling in 2011, but not recommending it for mainline inclusion, so I do not know if it has been added yet.

I also found a page at https://computing.llnl.gov/linux/slurm/gang_scheduling.html which explain how to implement it using the SLURM utility.

I am surprised that mint dooes not ship the b43 drivers by default it that distro does not appear to be friendly for offline use. But I did find a tutorial for you to try at http://community.linuxmint.com/tutorial/view/692