scsi_readcap man page

scsi_readcap — do SCSI READ CAPACITY command on disks


scsi_readcap [--brief] [--help] [--long] [--verbose] DEVICE [DEVICE]*


This bash shell script calls the sg_readcap utility on each given DEVICE. This will send a SCSI READ CAPACITY command to each DEVICE.

The default action of this script is to send the 10 byte cdb READ CAPACITY(10) command to each DEVICE. If a response indicates the number of blocks is greater than or equal to '2**32 - 1' then the READ CAPACITY(16) is sent and its response is output.


Arguments to long options are mandatory for short options as well.

-b, --brief

shortens the output to two hexadecimal numbers, both prefixed by '0x'. The first number is the number of blocks available and the second is the size of each blocks in bytes (e.g. '0x12a19eb0 0x200'). If an error is detected '0x0 0x0' is output and the script continues if there are more DEVICEs.

-h, --help

print out the usage message then exit.

-l, --long

the default is to send the READ CAPACITY(10) command (i.e. the 10 byte cdb variant). When this option is given the READ CAPACITY(16) command is sent. The latter command yields more information in its response.

-v, --verbose

increase level or verbosity.

Exit Status

The exit status of this script is 0 when it is successful. Otherwise the exit status is that of the last sg_readcap utility called. See the sg3_utils(8) man page.


Written by D. Gilbert

See Also

sg_readcap (sg3_utils)


May 2013 sg3_utils-1.36 SG3_UTILS