16.3.1 File type tests
These options test for particular types of files. (Everything's a file,
but not all files are the same!)
- ‘-b file’
- True if file exists and is a block special device.
- ‘-c file’
- True if file exists and is a character special device.
- ‘-d file’
- True if file exists and is a directory.
- ‘-f file’
- True if file exists and is a regular file.
- ‘-h file’
- ‘-L file’
- True if file exists and is a symbolic link.
Unlike all other file-related tests, this test does not dereference
file if it is a symbolic link.
- ‘-p file’
- True if file exists and is a named pipe.
- ‘-S file’
- True if file exists and is a socket.
- ‘-t fd’
- True if fd is a file descriptor that is associated with a
terminal.