Displays the free disk space of currently mounted file systems. This command differs from /usr/bin/df in several ways:
Blocks sizes are reported in units of 1024-bytes in this version of df, while /usr/bin/df uses 512-byte blocks.
Perhaps the most obvious difference between the two versions of this command is their output format, as shown by the example below.
$ /usr/ucb/df Filesystem kbytes used avail capacity Mounted on /dev/root 1750592 826496 749032 52% / $ df / (/dev/root ): 231024 blocks 105323 files /proc (/proc ): 0 blocks 123 files |