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`-P'
`--portability'
    Use the POSIX output format.  This is like the default format
    except for the following:

      1. The information about each file system is always printed on
         exactly one line; a mount device is never put on a line by
         itself.  This means that if the mount device name is more
         than 20 characters long (e.g., for some network mounts), the
         columns are misaligned.

      2. The labels in the header output line are changed to conform
         to POSIX.