# sg_raw(8) - man - phpman > **TLDR:** Send arbitrary SCSI command to a connected device. > - Send a command to an optical SCSI device assigned to `sr0` to load the media in its tray: `sg_raw /dev/sr0 EA 00 00 00 00 01` - Read data from `IFILE` instead of `stdin`: `sg_raw {{-i|--infile}} {{path/to/IFILE}} {{/dev/sgX}} {{scsi_command}}` - Skip the first `LEN` bytes of input data: `sg_raw {{-k|--skip}} {{LEN}} {{/dev/sgX}} {{scsi_command}}` - Read `SLEN` bytes of data and send to the device: `sg_raw {{-s|--send}} {{SLEN}} {{/dev/sgX}} {{scsi_command}}` - Wait up to `SEC` seconds for `sg_raw` to finish processing: `sg_raw {{-t|--timeout}} {{SEC}} {{/dev/sgX}} {{scsi_command}}` - Increase verbosity level by 1: `sg_raw {{-v|--verbose}} {{/dev/sgX}} {{scsi_command}}` - Dump returned data in binary form: `sg_raw {{-b|--binary}} {{/dev/sgX}} {{scsi_command}}` - Write data received from the specified device to an `OFILE`: `sg_raw {{-o|--outfile}} {{path/to/OFILE}} {{/dev/sgX}} {{scsi_command}}` *Source: tldr-pages* --- [SG_RAW(8)](https://www.chedong.com/phpMan.php/man/SGRAW/8/markdown) SG3_UTILS [SG_RAW(8)](https://www.chedong.com/phpMan.php/man/SGRAW/8/markdown) ## NAME sg_raw - send arbitrary SCSI or NVMe command to a device ## SYNOPSIS **sg**___**raw** [_--binary_] [_--cmdfile=CF_] [_--cmdset=CS_] [_--enumerate_] [_--help_] [_--infile=IFILE_] [_--nosense_] [_--nvm_] [_--outfile=OFILE_] [_--raw_] [_--readonly_] [_--request=RLEN_] [_--scan=FO,LO_] [_--send=SLEN_] [_--skip=KLEN_] [_--timeout=SECS_] [_--verbose_] [_--version_] _DEVICE_ [CDB0 CDB1 ...] ## DESCRIPTION This utility sends an arbitrary SCSI command (between 6 and 256 bytes) to the _DEVICE_. There may be no associated data transfer; or data may be read from a file and sent to the _DEVICE_; or data may be received from the _DEVICE_ and then displayed or written to a file. If supported by the pass through, bidirectional commands may be sent (i.e. containing both data to be sent to the _DEVICE_ and received from the _DEVICE_). The SCSI command may be between 6 and 256 bytes long. Each command byte is specified in plain hex format (00..FF) without a prefix or suffix. The command can be given either on the com‐ mand line or via the _--cmdfile=CF_ option. See EXAMPLES section below. The commands pass through a generic SCSI interface which is implemented for several operating systems including Linux, FreeBSD and Windows. Experimental support has been added to send NVMe Admin and NVM commands to the _DEVICE_. Since all NVMe commands are 64 bytes long it is more convenient to use the _--cmdfile=CF_ option rather than type the 64 bytes of the NVMe command on the command line. See the section on NVME below. A heuristic based on command length is used to decide if the given command is SCSI or NVMe, to override this heuristic use the _--cmdset=CS_ option. ## OPTIONS Arguments to long options are mandatory for short options as well. The options are arranged in alphabetical order based on the long option name. ### -b --binary Dump data in binary form, even when writing to stdout. ### -c --cmdfile _CF_ is the name of a file which contains the command to be executed. Without this op‐ tion the command must be given on the command line, after the options and the _DEVICE_. ### -C --cmdset _CS_ is a number to indicate which command set (i.e. SCSI or NVMe) to use. 0, the de‐ fault, causes a heuristic based on command length to be used. Use a _CS_ of 1 to over‐ ride that heuristic and choose the SCSI command set. Use a _CS_ of 2 to override that heuristic and choose the NVMe command set. ### -h --help Display usage information and exit. ### -i --infile Read data from _IFILE_ instead of stdin. This option is ignored if **--send** is not speci‐ fied. ### -n --nosense Don't display SCSI Sense information. ### -N --nvm When sending NVMe commands, the Admin command set is assumed. To send the NVM command set (e.g. the Read and Write (user data) commands) this option needs to be given. ### -o --outfile Write data received from the _DEVICE_ to _OFILE_. The data is written in binary. By de‐ fault, data is dumped in hex format to stdout. If _OFILE_ is '-' then data is dumped in binary to stdout. This option is ignored if _--request_ is not specified. ### -w --raw interpret _CF_ (i.e. the command file) as containing binary. The default is to assume that it contains ASCII hexadecimal. ### -R --readonly Open _DEVICE_ read-only. The default (without this option) is to open it read-write. ### -r --request Expect to receive up to _RLEN_ bytes of data from the _DEVICE_. _RLEN_ may be suffixed with 'k' to use kilobytes (1024 bytes) instead of bytes. _RLEN_ is decimal unless it has a leading '0x' or a trailing 'h'. If _RLEN_ is too small (i.e. either smaller than indicated by the cdb (typically the "allocation length" field) and/or smaller than the _DEVICE_ tries to send back) then the HBA driver may complain. Making _RLEN_ larger than required should cause no problems. Most SCSI "data-in" commands return a data block that contains (in its early bytes) a length that the _DEVICE_ would "like" to send back if the "allocation length" field in the cdb is large enough. In practice, the _DEVICE_ will return no more bytes than indi‐ cated in the "allocation length" field of the cdb. ### -Q --scan Scan a range of opcodes (i.e. first byte of each command). The first opcode in the scan is _FO_ (which is decimal unless it has a '0x' prefix or 'h' suffix). The last op‐ code in the scan is _LO_. The maximum value of _LO_ is 255. The remaining bytes of the SCSI/NVMe command are as supplied at invocation. Warning: this option can be **dangerous.** Sending somewhat arbitrary commands to a de‐ vice can have unexpected results. It is recommended that this option is used with the _--cmdset=CS_ option where _CS_ is 1 or 2 in order to stop the command set possibly chang‐ ing during the scan. ### -s --send Read _SLEN_ bytes of data, either from stdin or from a file, and send them to the _DE__‐ _VICE_. In the SCSI transport, _SLEN_ becomes the length (in bytes) of the "data-out" buf‐ fer. _SLEN_ is decimal unless it has a leading '0x' or a trailing 'h'. It is the responsibility of the user to make sure that the "data-out" length implied or stated in the cdb matches _SLEN_. Note that some common SCSI commands such as [WRITE(10)](https://www.chedong.com/phpMan.php/man/WRITE/10/markdown) have a "transfer length" field whose units are logical blocks (which are usually 512 or 4096 bytes long). ### -k --skip Skip the first _KLEN_ bytes of the input file or stream. This option is ignored if _--send_ is not specified. If _--send_ is given and this option is not given, then zero bytes are skipped. ### -t --timeout Wait up to _SECS_ seconds for command completion (default: 20). Note that if a command times out the operating system may start by aborting the command and if that is unsuc‐ cessful it may attempt to reset the device. ### -v --verbose Increase level of verbosity. Can be used multiple times. ### -V --version Display version and license information and exit. ## NOTES The sg_inq utility can be used to send an INQUIRY command to a device to determine its pe‐ ripheral device type (e.g. '1' for a streaming device (tape drive)) which determines which SCSI command sets a device should support (e.g. SPC and SSC). The sg_vpd utility reads and decodes a device's Vital Product Pages which may contain useful information. The ability to send more than a 16 byte CDB (in some cases 12 byte CDB) may be restricted by the pass-through interface, the low level driver or the transport. In the Linux series 3 ker‐ nels, the bsg driver can handle longer CDBs, block devices (e.g. /dev/sdc) accessed via the SG_IO ioctl cannot handle CDBs longer than 16 bytes, and the sg driver can handle longer CDBs from lk 3.17 . The CDB command name defined by T10 for the given CDB is shown if the '-vv' option is given. The command line syntax still needs to be correct, so /dev/null may be used for the _DEVICE_ since the CDB command name decoding is done before the _DEVICE_ is checked. The intention of the _--scan=FO,LO_ option is to slightly simplify the process of finding hid‐ den or undocumented commands. It should be used with care; for example checking for vendor specific SCSI commands: 'sg_raw --cmdset=1 --scan=0xc0,0xff /dev/sg1 0 0 0 0 0 0'. ## NVME SUPPORT Support for NVMe (a.k.a. NVM Express) is currently experimental. NVMe concepts map reasonably well to the SCSI architecture. A SCSI logical unit (LU) is similar to a NVMe namespace (al‐ though LUN 0 is very common in SCSI while namespace IDs start at 1). A SCSI target device is similar to a NVMe controller. SCSI commands vary from 6 to 260 bytes long (although SCSI com‐ mand descriptor blocks (cdb_s) longer than 32 bytes are uncommon) while all NVMe commands are currently 64 bytes long. The SCSI architecture makes a clear distinction between an initiator (often called a HBA) and a target (device) while (at least on the PCIe transport) the NVMe controller plays both roles. This utility defaults to assuming the user provided 64 byte command belongs to NVMe's Admin command set. To issue commands from the "NVM" command set, the _--nvm_ option must be given. Admin and NVM commands are sent to submission queue 0. One significant difference is that SCSI uses a big endian representation for integers that are longer than 8 bits (i.e. longer than 1 byte) while NVMe uses a little endian representa‐ tion (like most things that have originated from the Intel organisation). NVMe specifications talk about Words (16 bits), Double Words (32 bits) and sometimes Quad Words (64 bits) and has tighter alignment requirements than SCSI. One difference that impacts this utility is that NVMe places pointers to host memory in its commands while SCSI leaves this detail to whichever transport it is using (e.g. SAS, iSCSI, SRP). Since this utility takes the command from the user (either on the command line or in a file named _CF_) but this utility allocates a data-in or data-out buffer as required, the user does not know in advance what the address of that buffer will be. Some special addresses have been introduced to help with this problem: the address 0xfffffffffffffffe is interpreted as "use the data-in buffer's address" while 0xfffffffffffffffd is interpreted as "use the data-out buffer's address". Since NVMe uses little endian notation then that first address appears in the NVMe command byte stream as "fe" followed by seven "ff"s. A similar arrange‐ ment is made for the length of that buffer (in bytes), but since that is a 32 byte quantity, the first 4 bytes (all "ff"s) are removed. Several command file examples can be found in the examples directory of this package's source tarball: nvme_identify_ctl.hex, nvme_dev_self_test.hex, nvme_read_ctl.hex and nvme_write_ctl.hex . Beware: the NVMe standard often refers to some of its fields as "0's based". They are typi‐ cally counts of something like the number of blocks to be read. For example in NVMe Read command, a "0's based" number of blocks field containing the value 3 means to read 4 blocks! No, this is not a joke. ## EXAMPLES These examples, apart from the last one, use Linux device names. For suitable device names in other supported Operating Systems see the [sg3_utils(8)](https://www.chedong.com/phpMan.php/man/sg3utils/8/markdown) man page. sg_raw /dev/scd0 1b 00 00 00 02 00 Eject the medium in CD drive /dev/scd0. sg_raw -r 1k /dev/sg0 12 00 00 00 60 00 Perform an INQUIRY on /dev/sg0 and dump the response data (up to 1024 bytes) to std‐ out. sg_raw -s 512 -i i512.bin /dev/sda 3b 02 00 00 00 00 00 02 00 00 Showing an example of writing 512 bytes to a sector on a disk is a little dangerous. Instead this example will read i512.bin (assumed to be 512 bytes long) and use the SCSI WRITE BUFFER command to send it to the "data" buffer (that is mode 2). This is a safe operation. sg_raw -r 512 -o o512.bin /dev/sda 3c 02 00 00 00 00 00 02 00 00 This will use the SCSI READ BUFFER command to read 512 bytes from the "data" buffer (i.e. mode 2) then write it to the o512.bin file. When used in conjunction with the previous example, if both commands work then 'cmp i512.bin o512.bin' should show a match. sg_raw --infile=urandom.bin --send=512 --request=512 --outfile=out.bin "/dev/bsg/7:0:0:0" 53 00 00 00 00 00 00 00 01 00 This is a bidirectional [XDWRITEREAD(10)](https://www.chedong.com/phpMan.php/man/XDWRITEREAD/10/markdown) command being sent via a Linux bsg device. Note that data is being read from "urandom.bin" and sent to the device (data-out) while resulting data (data-in) is placed in the "out.bin" file. Also note the length of both is 512 bytes which corresponds to the transfer length of 1 (block) in the cdb (i.e. the second last byte). urandom.bin can be produced like this: dd if=/dev/urandom bs=512 count=1 of=urandom.bin sg_raw.exe PhysicalDrive1 a1 0c 0e 00 00 00 00 00 00 e0 00 00 This example is from Windows and shows a ATA STANDBY IMMEDIATE command being sent to PhysicalDrive1. That ATA command is contained within the SCSI ATA [PASS-THROUGH(12)](https://www.chedong.com/phpMan.php/man/PASS-THROUGH/12/markdown) command (see the SAT or SAT-2 standard at ). Notice that the STANDBY IMMEDIATE command does not send or receive any additional data, however if it fails sense data should be returned and displayed. ## EXIT STATUS The exit status of sg_raw is 0 when it is successful. Otherwise see the [sg3_utils(8)](https://www.chedong.com/phpMan.php/man/sg3utils/8/markdown) man page. ## AUTHOR Written by Ingo van Lil ## REPORTING BUGS Report bugs to or to . ## COPYRIGHT Copyright © 2001-2021 Ingo van Lil This software is distributed under the GPL version 2. There is NO warranty; not even for MER‐ CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ## SEE ALSO **sg**___**inq,** **sg**___**vpd,** **sg3**___**utils** **(sg3**___**utils),** **plscsi** sg3_utils-1.46 January 2021 [SG_RAW(8)](https://www.chedong.com/phpMan.php/man/SGRAW/8/markdown)