Suppose that you have a chunk of Python code that wants to properlymap IP addresses to hostnames , and you wantto test this code to make sure that it actually works (especially withunit tests). In order to do this you need to contrive for various IPaddress and hostname lookups to fail in various ways, and to do thison command.

The easy way to do this is to exploit Python's freedom by shimming (well, replacing) the gethostbyname() and gethostbyaddr() functions in the

People can talk about the risks of not changing passwords at the dropof a hat, but they rarely talk about the risks of forcing people to gothrough frequent password changes. This matters a lot, because thereare significant risks.

(And when people do acknowledge the risks, often it is to decry or mockthe 'bad habits' that people adopt.)

The obvious problems are that people can't remember things at the dropof a hat just because you want them to, and people have trouble coming

The problem with a search for alternatives to the Bourne shell is that the Bourne shell isstill one of the best Unix programming languages. Or perhaps it wouldbe clearer to call it a 'Unix glue language', a language for connectingexisting programs together.

You might sensibly ask what the problems are with things like Perl andPython as Unix glue languages, and my answer would be that they make ittoo hard to interact with external programs. This is important, becausethe way you write small programs fast on Unix