NAME
fscat (vxfs) — cat a VxFS file system
SYNOPSIS
/usr/sbin/fscat
[-F
vxfs]
[-V]
[-o
offset]
[-l
length]
[-b
block_size]
special
DESCRIPTION
The
fscat
utility provides an interface to a VxFS snapshot file system similar
to that provided by the
dd
utility invoked on the special file of other VxFS file systems.
On most VxFS file systems, the block or character special file for
the file system provides
access to a raw image of the file system for purposes such as backing
up the file system to tape.
On a snapshot file system,
access to the corresponding block or character special provides
little useful information.
The
fscat
utility, however,
provides a stream of bytes representing the file system snapshot.
This stream can be processed several ways,
such as being processed in a pipeline,
being written to a tape,
and so on.
fscat
will work when executed on the device special file of any VxFS
file system.
By default,
the output is a stream of bytes that starts at the beginning of
the file system and continues to the last byte.
On a snapshot file system,
data is read from the file system using the VX_SNAPREAD
ioctl on the mount point.
On other VxFS file systems,
data is read from the
specified
special.
Data is written to standard output.
All numbers entered as option arguments may have
0
prepended to indicate octal,
or
0x
prepended to indicate hexadecimal. A
b
may be appended to indicate the value is in 512-byte blocks,
a
k
to indicate the value is in kilobytes,
or an
m
to indicate the value is in megabytes.
An appended letter may be separated from the number by a space,
in which case the letter and number should be enclosed in a
set of quotes (for example,
"
512 b
").
Options
- -F vxfs
Specifies the VxFS file system type.
- -V
Echoes the completed command line, but performs no other action.
The command line is generated by incorporating the user-specified
options. This option allows the user to verify the command line.
- -o offset
Specify the transfer start offset within the file system, in bytes.
- -l length
Specify the transfer length, in bytes.
A
length
of
0
includes the remainder of the file system after the specified offset.
- -b block_size
Specify the output block size, in bytes.
block_size
must be less than or equal to 1 megabyte.
NOTES
fscat
is only available with the VxFS Advanced package.
A snapshot file system cannot be written to.
A snapshot file system exists only as long as it is mounted;
once unmounted,
the special file no longer contains a snapshot file system.
