du.1

早期freebsd实现

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.\"	@(#)du.1	8.2 (Berkeley) 4/1/94
.\"
.Dd April 1, 1994
.Dt DU 1
.Os
.Sh NAME
.Nm du
.Nd display disk usage statistics
.Sh SYNOPSIS
.Nm du
.Op Fl H | Fl L | Fl P
.Op Fl a | Fl s
.Op Fl x
.Op Ar file ...
.Sh DESCRIPTION
The
.Nm du
utility displays the file system block usage for each file argument
and for each directory in the file hierarchy rooted in each directory
argument.
If no file is specified, the block usage of the hierarchy rooted in
the current directory is displayed.
The number of blocks are in the same units as that returned by the
.Xr stat 2
system call, i.e. 512-byte blocks.
Partial numbers of blocks are rounded up.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl H
Symbolic links on the command line are followed.
(Symbolic links encountered in the tree traversal are not followed.)
.It Fl L
All symbolic links are followed.
.It Fl P
No symbolic links are followed.
.It Fl a
Display an entry for each file in the file hierarchy.
.It Fl s
Display only the grand total for the specified files.
.It Fl x
Filesystem mount points are not traversed.
.El
.Pp
.Nm Du
counts the storage used by symbolic links and not the files they
reference unless the
.Fl H
or 
.Fl L 
option is specified.
If either the
.Fl H
or
.Fl L
options are specified, storage used by any symbolic links which are
followed is not counted or displayed.
The
.Fl H ,
.Fl L
and
.Fl P
options override each other and the command's actions are determined
by the last one specified.
.Pp
Files having multiple hard links are counted (and displayed) a single
time per
.Nm du
execution.
.Sh ENVIRONMENTAL VARIABLES
.Bl -tag -width BLOCKSIZE
.It Ev BLOCKSIZE
If the environmental variable
.Ev BLOCKSIZE
is set, the block counts will be displayed in units of that size block.
.El
.Sh SEE ALSO
.Xr df 1 ,
.Xr fts 3 ,
.Xr symlink 7 ,
.Xr quot 8
.Sh HISTORY
A
.Nm du
command appeared in
.At v6 .