Why pass the program name as a parameter to main?

If I 开发者_高级运维call:

./program hello world

then:

argc would be 3.
argv[0] would be "./program".
argv[1] would be "hello".
argv[2] would be "world".

What's the purpose of passing "./program" as an argument? In fact, it's not an argument at all!

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You can make symbolic links to the same binary. Depending on what link you use, you will get different behaviour. Busybox is an example of this.

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One use is so that the application can know how it was invoked (essentially, what its own name is).

Note that what appears in argv[] is implementation-defined. If you use one of the UNIX exec() functions, for instance, the contents can be whatever you like.

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...and you can make make a nice help-function that display a help-text when invoked that doesn't need to be updated when the name of the executable changes.