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.

`-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 opened on a terminal. If fd is omitted, it defaults to 1 (standard output).