HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

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fscat_vxfs(1M) fscat_vxfs(1M)

NAME

fscat - cat a VxFS ﬁle system

SYNOPSIS

/usr/sbin/fscat

[-F vxfs][-f output-ﬁle][

-o offset][-l length][-b

block_size] special

DESCRIPTION

fscat provides an interface to a VxFS snapshot ﬁle system similar to that provided by

dd invoked on the

block or character special ﬁle of regular 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 to back up the ﬁle system to tape. On a snapshot ﬁle system, access to the

corresponding block or character special ﬁle provides little useful information.

fscat

provides a stream

of bytes representing the ﬁle system snapshot. This datastream is written by default to standard output,

although the

-f output-ﬁle option can be used to specify another destination. The datastream on standard

output can be processed several ways, such as in a pipeline, or written to a tape.

fscat works when exe-

cuted on the special device 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 special ioctls on the mount

point. On other VxFS ﬁle systems, data is read from the speciﬁed special ﬁle. Unless otherwise speciﬁed,

data is written to standard output.

All numbers entered as option arguments may have

0 as a preﬁx to indicate octal, or

0x as a preﬁx to

indicate hexadecimal. A

b or B may be appended to indicate the value is in 512-byte blocks, a

k or K to

indicate the value is in kilobytes, an

m or M to indicate the value is in megabytes, or a

g or G to indicate

the value is in gigabytes. 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"

All numbers entered as options must be in multiples of 512 bytes. For example, a value of 5713 as an offset

is rejected.

Options

-b block_size Specify the output block size, in bytes. block_size must be less than or equal to 1 megabyte.

-F vxfs Specify the VxFS ﬁle system type.

-f output-file Specify an output ﬁle in which to write the datastream.

-l length Specify the transfer length, in bytes. A length of 0 includes the remainder of the ﬁle sys-

tem after the speciﬁed offset.

-o offset Specify the starting offset in bytes.

NOTES

Snapshot ﬁle systems are only available with the HP OnLineJFS product.

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.