Usage
The SUS mandates the following options:
- -M file, specify a file specially formatted containing position-sensitive tests; default position-sensitive tests and context-sensitive tests will not be performed
- -m file, as for -M, but default tests will be performed after the tests contained in file.
- -d, perform default position-sensitive and context-sensitive tests to the given file; this is the default behaviour unless -M or -m is specified
- -h, do-not-dereference symbolic links that point to an existing file or directory
- -L, dereference the symbolic link that points to an existing file or directory
- -i, do not classify the file further than to identify it as either: nonexistent, a block special file, a character special file, a directory, a FIFO, a socket, a symbolic link, or a regular file
Other Unix and Unix-like operating systems may add extra options than these.
The command tells only what the file looks like, not what it is (in the case where file looks at the content). It is easy to fool the program by putting a magic number into a file the content of which does not match it. Thus the command is not usable as a security tool other than in specific situations.
Read more about this topic: File (command)
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