# phpman > man > SG_OPCODES(8) [SG_OPCODES(8)](https://www.chedong.com/phpMan.php/man/SGOPCODES/8/markdown) SG3_UTILS [SG_OPCODES(8)](https://www.chedong.com/phpMan.php/man/SGOPCODES/8/markdown) ## NAME sg_opcodes - report supported SCSI commands or task management functions ## SYNOPSIS **sg**___**opcodes** [_--alpha_] [_--compact_] [_--enumerate_] [_--help_] [_--hex_] [_--mask_] [_--mlu_] [_--no-in__‐ _quiry_] [_--opcode=OP[,SA]_] [_--pdt=DT_] [_--raw_] [_--rctd_] [_--repd_] [_--sa=SA_] [_--tmf_] [_--unsorted_] [_--verbose_] [_--version_] _DEVICE_ **sg**___**opcodes** [_-a_] [_-c_] [_-e_] [_-H_] [_-m_] [_-M_] [_-n_] [_-o=OP_] [_-p=DT_] [_-q_] [_-R_] [_-s=SA_] [_-t_] [_-u_] [_-v_] [_-V_] [_-?_] _DEVICE_ ## DESCRIPTION This utility sends a SCSI REPORT SUPPORTED OPERATION CODES or a REPORT SUPPORTED TASK MANAGE‐ MENT FUNCTIONS command to the _DEVICE_ and then outputs the response. The default action is to report supported operation codes. In this mode it will either list all supported commands or give detailed information on a specific command identified by the _--opcode=OP_ option (perhaps with additional information from the _--sa=SA_ option). The name of a SCSI command depends on its peripheral device type (e.g. a disk). The REPORT SUPPORTED OPERATION CODES and REPORT SUPPORTED TASK MANAGEMENT FUNCTIONS commands are not supported in the MMC command set for CD and DVD devices. This utility does an INQUIRY to ob‐ tain the peripheral device type and prints out the vendor, product and revision strings. A similar facility to query supported operation codes previously was available via the CmdDt bit in the SCSI INQUIRY command (see [sg_inq(8)](https://www.chedong.com/phpMan.php/man/sginq/8/markdown)). However that facility was made obsolete and replaced by the REPORT SUPPORTED OPERATION CODES command in SPC-3 (revision 4) during Febru‐ ary 2002. This utility supports two command line syntaxes, the preferred one is shown first in the syn‐ opsis and explained in this section. A later section on the old command line syntax outlines the second group of options. ## OPTIONS Arguments to long options are mandatory for short options as well. ### -a --alpha when all supported commands are being listed there is no requirement for the device server (i.e. the _DEVICE_) to sort the list of commands. When this option is given the list of supported commands is sorted by name (alphabetically). When this option and the **--unsorted** option are both _not_ given then the list of supported commands is sorted numerically (first by operation code and then by service action). ### -c --compact some command names, especially those associated with some service actions, are getting longer. This may cause line wrap in the one line per command mode on some terminals. When this option is given the opcode and service action fields are combined into a single field with the service action, prefixed by a comma shown directly after the op‐ code. If there is no service action associated with the command, then the comma and the service action are not shown after the opcode. The CDB size field is not shown when this option is given. ### -e --enumerate this option prints the name of the SCSI command based on the given opcode, peripheral device type and optionally the service action. If given, _DEVICE_ is ignored. The op‐ code, peripheral device type and service action default to zero if not given. Thus if this option is the only option given then "Test Unit ready" is output since its opcode is 0, it has no service action and it is common to all peripheral device types since it is defined in the SCSI Primary Commands (SPC) standard(s). ### -h --help outputs the usage message summarizing command line options then exits. Ignores _DEVICE_ if given. ### -H --hex outputs the response in ASCII hexadecimal to stdout. ### -m --mask additionally prints out the cdb mask in hex. So a 12 byte cdb will have a 12 byte hexadecimal mask. If the hexadecimal is expanded (mentally) to binary then a "1" means the corresponding position in the cdb may be set. And "0" means the corresponding po‐ sition in the cdb must not be set. For "0" mask positions that a user tries to set in a cdb, the device may either ignore it or report an error, typically with a sense key of "illegal request". ### -M --mlu additionally prints out an indication (0 or 1) whether the command effects all logical units in the containing target. MLU (Multiple Logical Units) is a bit in the REPORT SUPPORTED OPERATION CODES response introduced by proposal 18-045r1 (and possibly in spc5r20). Without the option, the default output format which lists all opcodes, does not include a MLU indication. ### -n --no-inquiry Prior to calling a SCSI REPORT SUPPORTED OPERATION CODES or a REPORT SUPPORTED TASK MANAGEMENT FUNCTIONS command, a SCSI INQUIRY command is performed. The reason is to determine the peripheral device type (pdt) of the _DEVICE_ as this is helpful in trans‐ lating operation codes to the command names. By default this utility prints a summary of INQUIRY command response on stdout. If this option (or the _--raw_ option) is given then that summary is not printed on stdout. ### -O --old Switch to older style options. Please use as first option. ### -o --opcode the _DEVICE_ will be queried for the given operation code (i.e. the _OP_ value) which is the first byte of a SCSI command. Optionally, if a _SA_ value is given, it will be used as that SCSI command's service action. Note that _OP_ and _OP,0_ are not the same thing, as SCSI does allow the service action to be 0 (but it is not comman). _OP_ and _SA_ are decimal unless prefixed by "0x" or they have a trailing "h". _OP_ should be in the range 0 to 255 (0xff) inclusive. _SA_ should be in the range 0 to 65535 (0xffff) inclu‐ sive. When this option is not given then all available SCSI commands supported by the _DEVICE_ are listed. ### -p --pdt where _DT_ is the peripheral device type. This is used together with the _--enumerate_ to differentiate when a command opcode (and perhaps service action) is shared by multiple device types. This option may also be used with the _--no-inquiry_ option to suppress this utility do‐ ing an INQUIRY command since the main reason for doing that is to find the peripheral device type of the _DEVICE_. ### -r --raw output the response in binary to stdout. Error messages and warnings, if any, are sent to stderr. ### -R --rctd set report command timeout descriptor (RCTD) bit in the cdb. The response may or may not contain command timeout descriptors. If available they are output. If supported there are two values: a nominal command timeout and a recommended command timeout. Both have units of seconds. A value of zero means that no timeout is indicated and this is shown in the corresponding decoded output as "-". ### -q --repd set read extended parameter data (REPD) bit in the report task management functions cdb. 16 bytes rather than the default 4 bytes expected in the response. This was added in SPC-4 (revision 26). ### -s --sa the _DEVICE_ will be queried for a command with the given service action (i.e. the _SA_ value). Used in conjunction with the _--opcode=OP_ option. If this option is not given, _--opcode=OP_ is given and the command in question does have a service action then a value of 0 will be assumed. _SA_ is decimal and expected to be in the range 0 to 65535 (0xffff) inclusive. ### -t --tmf list supported task management functions. This is done with the SCSI REPORT SUPPORTED TASK MANAGEMENT FUNCTIONS command. When this option is chosen the _--alpha_, _--op__‐ _code=OP_, _--rctd_, _--sa=SA_ and _--unsorted_ options are ignored. ### -u --unsorted when all supported commands are being listed there is no requirement for the device server (i.e. the _DEVICE_) to sort the list of commands. When this option is given the list of supported commands is in the order given by the _DEVICE_. When this option is not given the supported commands are sorted numerically (first by operation code and then by service action). ### -v --verbose increase level of verbosity. Can be used multiple times. ### -V --version print out version string then exit. ## NOTES As of SPC-5 revision 8 the recognized task management functions are: abort set, abort task set, clear ACA, clear task set, logical unit reset, query task, query asynchronous event, query task set, and I_T nexus reset. In SPC-4 revision 26 target reset and wakeup task man‐ agement functions were made obsolete. In the 2.4 series of Linux kernels the _DEVICE_ must be a SCSI generic (sg) device. In the 2.6 series block devices (e.g. SCSI disks and DVD drives) can also be specified. For example "sg_opcodes /dev/sda" will work in the 2.6 series kernels. ## EXIT STATUS The exit status of sg_opcodes is 0 when it is successful. Otherwise see the [sg3_utils(8)](https://www.chedong.com/phpMan.php/man/sg3utils/8/markdown) man page. ## OLDER COMMAND LINE OPTIONS The options in this section were the only ones available prior to sg3_utils version 1.23 . Since then this utility defaults to the newer command line options which can be overridden by using _--old_ (or _-O_) as the first option. See the ENVIRONMENT VARIABLES section for another way to force the use of these older command line options. ### -a ### -c ### -e ### -H ### -m ### -n ### -N --new Switch to the newer style options. ### -o byte of a SCSI command. _OP_ is hexadecimal and expected to be in the range 0 to ff in‐ clusive. When this option is not given then all available SCSI commands supported by the _DEVICE_ are listed. ### -p ### -q _--repd_ in main description. ### -R main description. ### -s in conjunction with the _-o=OP_ option. If this option is not given, _-o=OP_ is given and the command in question does have a service action then a value of 0 will be assumed. _SA_ is hexadecimal and expected to be in the range 0 to ffff inclusive. ### -t ### -u in main description. ### -v ### -V **-?** output usage message. Ignore all other parameters. ## EXAMPLES The examples in this page use Linux device names. For suitable device names in other sup‐ ported Operating Systems see the [sg3_utils(8)](https://www.chedong.com/phpMan.php/man/sg3utils/8/markdown) man page. To see the information about a specific command give its operation code to the '--op=' op‐ tion. A command line invocation is shown first followed by a typical response: # sg_opcodes --op=93h /dev/sdb Opcode=0x93 Command_name: Write [same(16)](https://www.chedong.com/phpMan.php/man/same/16/markdown) Command supported [conforming to SCSI standard] Usage data: 93 e2 00 00 00 00 ff ff ff ff 00 00 ff ff 00 00 The next example shows the supported task management functions: # sg_opcodes --tmf -n /dev/sdb Task Management Functions supported by device: Abort task Abort task set Clear ACA Clear task set Logical unit reset Query task Enumerate can be used to look up a SCSI command name in the absence of a device that supports that command. The opcode and service action (if required) should be supplied: # sg_opcodes --enumerate --op=0x9b,0xa SCSI command: Read [buffer(16)](https://www.chedong.com/phpMan.php/man/buffer/16/markdown), read data from echo buffer ## ENVIRONMENT VARIABLES Since sg3_utils version 1.23 the environment variable SG3_UTILS_OLD_OPTS can be given. When it is present this utility will expect the older command line options. So the presence of this environment variable is equivalent to using _--old_ (or _-O_) as the first command line op‐ tion. ## AUTHOR Written by Douglas Gilbert ## REPORTING BUGS Report bugs to . ## COPYRIGHT Copyright © 2004-2021 Douglas Gilbert 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(sg3**___**utils)** sg3_utils-1.46 March 2020 [SG_OPCODES(8)](https://www.chedong.com/phpMan.php/man/SGOPCODES/8/markdown)