freebsd-dev/usr.sbin/getextattr/getextattr.8
2001-07-05 07:23:24 +00:00

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.\" Copyright (c) 2000, 2001 Robert N. M. Watson
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.Dd March 30, 2000
.Dt GETEXTATTR 8
.Os
.Sh NAME
.Nm getextattr
.Nd retrieve a named extended attribute
.Sh SYNOPSIS
.Nm
.Op Fl ls
.Ar attrnamespace
.Ar attrname
.Ar filename ...
.Sh DESCRIPTION
.Nm
is a user tool to retrieve a named extended attribute on a file or
directory.
The
.Ar attrnamespace
argument should be the namespace of the attribute to retrieve: legal
values are "user" and "system".
The
.Ar attrname
argument should be the name of the attribute, and
.Ar filename
a list of files and directories from which to retrieve attribute data.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl l
Print attributes in the first column and file names in the second.
Can be used only in conjunction with the
.Fl s
option.
.It Fl s
Attempt to display the attribute data as a string, although the
results may not look pretty if the data is binary data.
The
.Xr strvisx 3
function is used to generate the string, so control sequences should
be safely escaped.
Otherwise, the attribute data will be represented as a series of two-digit
hex numbers.
.El
.Sh IMPLEMENTATION NOTES
In order for
.Nm
to succeed, the attribute service must be available on the file system,
and the attribute must of defined for the file queried.
.Sh EXAMPLES
.Bd -literal -offset indent
# getextattr system md5 /kernel
/kernel:
61 61 33 62 39 39 66 65 31 35 35 32 31 62 65 32
62 36 38 36 62 31 66 39 63 64 33 39 35 36 36 31
# getextattr -s system md5 /kernel
/kernel: "aa3b99fe15521be2b686b1f9cd395661"
.Ed
.Pp
Retrieve the
.Dq md5
extended attribute for the file
.Pa /kernel .
.Sh SEE ALSO
.Xr extattr 2 ,
.Xr extattr 3 ,
.Xr extattrctl 8 ,
.Xr setextattr 8 ,
.Xr extattr 9
.Sh HISTORY
Extended attribute support was developed as part of the TrustedBSD Project,
and introduced in
.Fx 5.0 .
It was developed to support security extensions requiring additional labels
to be associated with each file or directory.
.Sh AUTHORS
Robert N M Watson
.Sh BUGS
Only the first 2048 bytes of the extended attribute value are displayed
due to a hard-coded buffer limit.