Very Computer

Hi,

any one knows if there is a way to find out if a file is excutable
without using the command 'file'?

I don't mean just simply accessing the status info and look at the
file mode.  Is there a c function or some sort that can actually
enable us to know if the file is executable.

Tao.

ps.  executable doesn't include script files.

Thanks in advanced.

Quote:> Hi,
> any one knows if there is a way to find out if a file is excutable
> without using the command 'file'?
> I don't mean just simply accessing the status info and look at the
> file mode.  Is there a c function or some sort that can actually
> enable us to know if the file is executable.

No,  you have to do what the file command does, which is to read a
small portion of the beginning of the file, and guess what type of
file it is.  For executables, different versions of Unix have a
different "magic numbers", as they are called, at a specific byte
offset in the file.
There's no portable way to tell.  (FYI, IBM's AIX can't even tell
the difference between an executable and an object file - they have
the same magic number.)

See the file /etc/magic or the magic man page if you have one.

Hope this helps,
Dave

BTW, email failed (for obvious reasons):
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