Cisco CMTS Router ROM Monitor Commands

alias

To define an alias to be used at the ROM monitor prompt, use the alias command in ROM monitor mode.

alias [name=value]

Syntax Description

[name=value]

(Optional) Specifies the name of the alias to be defined and its corresponding command string. If the value parameter includes spaces, you must include the string within double quotes.

Command Default

If no arguments are given, displays the aliases that are currently defined.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

Aliasing allows you to abbreviate commands or to set up a command so that it is automatically run with certain options. The ROM monitor’s [name=value] alias function is based on the syntax used in the Korn shell on Unix systems.

Normally, only the first word at the ROM monitor prompt is checked for an alias. However, when you define an alias that contains a space as its last character, the ROM monitor also checks the next word at the ROM monitor prompt for an alias.


Note


If an alias contains any spaces, the entire command must be enclosed within quotes when you define it with the alias command. To create an alias for multiple commands, separate the commands with a semicolon (;) delimiter.

Tip


Use the unalias command to delete an alias.


Examples

The following example shows how to display the currently defined aliases:


rommon 13 > alias
 
r=repeat
h=history
?=help
b=boot
ls=dir
i=reset
k=stack
rommon 14 > 

The following example defines an alias named “cpuinfo” that executes three separate CPU-related commands:


rommon 31 > alias cpuinfo="cpu_card_type;meminfo;context"
 
rommon 32 > 

The following example shows how to define an alias dird that lists the file contents of the Flash Disk in the disk0 slot:


rommon 18 > alias dird="dir disk0:"
 
rommon 19 > alias
 
r=repeat
h=history
?=help
b=boot
ls=dir
i=reset
k=stack
dird=dir disk0:
rommon 20 > 

boot

To boot a router manually, use the boot command in ROM monitor mode.

boot [-xv]

boot [-xv] [device:] [imagename]

boot [-xv] filename [tftp-ip-address]

boot [-xv] tftp://server/path/filename

Syntax Description

x

(Optional) Loads the specified image into the router’s memory but does not execute it.

v

(Optional) Enables verbose mode to display debugging information as the image is loaded and executed.

device:

(Optional) Specifies that the router should boot an image on the specified device. If not specified, the router boots from the default memory device.

imagename

(Optional) Specifies the filename for the image to be booted and loaded. If not specified, the router boots the first file on the specified device.

Note

 
When specifying both a device: and imagename , do not put any spaces between the two arguments.

filename

Specifies the path and filename for the image that the router should download from a Trivial File Transfer Protocol (TFTP) server.

Note

 
You must specify the full path for the desired file, as it exists on the TFTP server.

tftp-ip-address

(Optional) Specifies the IP address for the TFTP server from which the router should download and boot the specified filename . If not specified, the router sends a TFTP request to the IP broadcast address of 255.255.255.255 and uses the first TFTP server that responds.

tftp://server/path/filename

Specifies the complete TFTP URL for the filename to be downloaded and run. This URL should specify the fully-qualified server name (or IP address), full path on the TFTP server, and filename to be downloaded.

Command Default

If specified without any options, the boot command loads and executes the first file on the default memory device. If a device is specified without a filename , the boot command loads and executes the first file on that device. If a filename is specified without a TFTP server IP address, the boot command advertises for a TFTP server using the IP broadcast address of 255.255.255.255 and uses the first TFTP server that responds.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The boot command allows a network administrator to boot the router from the ROM monitor (ROMMON) prompt. The router can enter ROMMON for the following reasons:

  • The administrator interrupted the boot sequence or Cisco IOS software by pressing the BREAK signal.
  • The router’s configuration register is set to boot into ROMMON (0x00).
  • The router entered ROMMON because of a software exception or error.

The boot command allows the administrator to continue the boot process or to load a new software image.


Note


To upgrade the router to a new Cisco IOS software image, you can use either the boot command in ROMMON mode or the boot system commands in global configuration mode.

Boot Changes in Cisco IOS Release 12.2

Cisco IOS Release 12.2 changed the behavior of the ROM monitor (ROMMON) during the bootup sequence. Previously, users could issue the break signal during the bootup sequence to break into ROMMON, and then immediately boot a new Cisco IOS image using the boot command.

This behavior is no longer allowed when the router is using a boot image that is based on Cisco IOS Release 12.2, because interrupting the boot process could leave the hardware and software registers in an unknown state. Instead, use the following procedure when using a router with a Cisco IOS Release 12.2 boot image:

  1. At the router's console prompt, send a BREAK signal to interrupt the boot process and enter ROMMON.
  2. Set the configure register to boot into ROMMON by giving the confreg 0x0 command.
  3. Use the reset command to reset the NPE and to boot into ROMMON. This ensures a clean boot into ROMMON, with all registers set to a known state.
  4. Set the configure register to boot an IOS image by giving the confreg 0x2102 command.
  5. Use the boot command to boot the desired Cisco IOS image.

Examples

The following example shows how to boot the router using the first file in the default device:


rommon 1 > boot
 
Self decompressing the image :
#######################################################################################
[OK]
(Software image boots...)
Router> 

The following example shows how to specify that the router should download and boot the file named “newimage.bin” in the subdirectory named “ubrimages” on the TFTP server with the IP address of 10.10.10.31:


rommon 45> boot tftp://10.10.10.31/ubrimages/newimage.bin
 
Self decompressing the image :
#######################################################################################
[OK]
(Software image boots...)
Router> 

The following example shows how to use the alternate syntax to specify that the router should download and boot the file named newimage.bin on the TFTP server with the IP address of 10.10.10.31:


rommon 45> boot newimage.bin 10.10.10.31
 
Self decompressing the image :
#######################################################################################
[OK]
(Software image boots...)
Router> 

The following example shows the new ROMMON boot procedure that is required when using a Cisco IOS Release 12.2 (or later) boot image:


Router-NPE#
telnet> send brk
 
*** System received an abort due to Break Key ***
signal= 0x3, code= 0x0, context= 0x6208b290
PC = 0x606b5ab0, SP = 0x80007e00, RA = 0x606d2370
Cause Reg = 0xffffffff, Status Reg = 0x3400ff03
rommon 2 > boot flash:newiosimage.bin
 
Please reset before booting
rommon 3 > confreg 0x0
 
You must reset or power cycle for new config to take effect
rommon 4 > reset
 
System Bootstrap, Version 12.2(11)BC3a, RELEASE SOFTWARE (fc1)
Copyright (c) 2002 by cisco Systems, Inc.
UBR7200 platform with 524288 Kbytes of main memory
rommon 1 > boot flash:newiosimage.bin
 
Self decompressing the image :
#######################################################################################
[OK]
(Software image boots...)
Router>
 

break

To set or clear the debugger breakpoint, use the break command in ROM monitor mode.

break [-s address | -c]

Syntax Description

-s address

(Optional) Sets the breakpoint to the specified address in memory. The address must be specified in hexadecimal.

-c

(Optional) Clears the currently-defined breakpoint.

Command Default

If no arguments are given, the command displays the currently-defined breakpoint.

Command Modes


ROM monitor

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The ROM monitor supports one breakpoint. If set, the processor runs normally, but when its program counter reaches the breakpoint address, the system breaks into ROM monitor mode. You can examine memory locations or register contents, and then continue normal program execution by using the cont command.

Examples

The following example shows how to set a breakpoint so that when the processor breaks into ROM monitor mode when its program counter reaches 0xbfc02708:


rommon 37 > break -s 0xbfc02708 
breakpoint set to 0xbfc02708
rommon 38 > 

The following example shows how to display the currently-defined breakpoint:


rommon 38 > break
 
breakpoint set to 0xbfc02708 
rommon 39 >

The following example shows how to clear the currently-defined breakpoint:


rommon 39 > break -c 
breakpoint is cleared
rommon 40 > 

confreg

To change the value of the router’s configuration register, use the confreg command in ROM monitor mode.

confreg [value]

Syntax Description

value

(Optional) New value for the configuration register, expressed as a 16-bit hexadecimal value. The valid range for value is 0x0 to 0xFFFF. If value is not specified, the command interactively prompts you for the individual register settings.

Command Default

0x2102 (boots the Cisco IOS software image and allows the use of the BREAK signal to enter ROMMON)

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The configuration register determines the router’s behavior when it boots. Typically, an administrator changes the configuration register so that it boots either into ROMMON mode or boots a Cisco IOS software image, but other options are also available.

If given without an argument, the confreg command interactively prompts you for the new values of the individual register settings, using English descriptions. You can either keep the current settings unchanged or change them as desired. The new value of the configuration register is written into the router’s nonvolatile Flash memory (NVRAM) immediately, but does not take effect until you reset the router.

If you specify an argument with the confreg command, it must be a 16-bit hexadecimal value in the following format:

Table 1. Configuration Register Bit Field Descriptions

Bit

Description

15

If set, enables the router’s diagnostic mode (for example, 0x8000).

14

If set, uses the network number in IP broadcasts (for example, 0x4000).

13

If set, allows the router to fall back into ROMMON mode if the boot procedure fails. If not set, the router attempts each valid boot command (as specified by bits 3–0) for a total of 5 times each, until one of the commands is successful (for example, 0x2000).

12–11

Defines the speed, in bps, for the console port:

00 = 0x0000 = 9600 01 = 0x0800 = 4800 10 = 0x1000 = 1200 11 = 0x1800 = 2400

Note

 
On the Cisco CMTS routers, the console port speed is fixed at 9600 bps and cannot be changed.

10

If set, uses an IP broadcast address that consists of all ones (for example, 0x0400).

9

If set, disables the secondary bootstrap (for example, 0x0200).

8

If set, the router enables the BREAK key, allowing users to break into ROMMON during the boot process (for example, 0x0100).

7

Unused on the Cisco CMTS routers.

6

If set, the router ignores the configuration file in its Flash memory. This is typically done when the user has forgotten the router’s enable password (for example, 0x0040).

5–4

Unused on the Cisco CMTS routers.

3–0

Defines the router’s boot behavior:

0x0000 = Boots to the ROMMON prompt 0x0001 = Boots the ROMMON boot helper software (first file in bootflash:) 0x0002 to 0x000F = Boots a Cisco IOS software image, based on the values of the router’s boot variables. Each boot system command in the configuration file is tried until a valid image is booted.

For example, for normal operations the configuration register is set to 0x2102, which sets bit 13 (allows the router to fall into ROMMON mode if the boot fails), bit 8 (allows the user to break into ROMMON), and bit 1 (boots a Cisco IOS software image). Bits 11 and 12 are cleared, which sets the console port to 9600 bps.

The following are the most commonly-used configuration register values:

  • 0x0 = Boot into ROMMON.
  • 0x2002 = Normal boot for standard operations, but the BREAK signal cannot be used to break into ROM monitor mode.
  • 0x2102 = Normal boot for standard operations, enabling the BREAK signal.
  • 0x2142 = Normal boot but the router ignores the configuration file in Flash memory.

Tip


The confreg command is identical in function to the config-register command that is available in global configuration mode.


Examples

The following example shows how to change the configuration register by using the English prompts. In this example, the only change is to have the router boot the Cisco IOS software image instead of entering ROMMON mode:


rommon 1 > confreg
 
    Configuration Summary
enabled are:
break/abort has effect
console baud: 9600
boot: the ROM Monitor 
do you wish to change the configuration? y/n  [n]:  y
 
enable  "diagnostic mode"? y/n  [n]:  
enable  "use net in IP bcast address"? y/n  [n]:  
enable  "load rom after netboot fails"? y/n  [n]:  
enable  "use all zero broadcast"? y/n  [n]:  
disable "break/abort has effect"? y/n  [n]:  
enable  "ignore system config info"? y/n  [n]:  
change console baud rate? y/n  [n]:  
change the boot characteristics? y/n  [n]:  y
 
enter to boot:
 0 = ROM Monitor
 1 = the boot helper image
 2-15 = boot system
    [0]:  2
 
    Configuration Summary
enabled are:
break/abort has effect
console baud: 9600
boot: image specified by the boot system commands
      or default to: cisco2-C10000 
do you wish to change the configuration? y/n  [n]: n
 
         You must reset or power cycle for new config to take effect.
rommon 2 > 


Note


After changing the configuration register in interactive mode, the system displays the new values and prompts you again as to whether you want to change them. If the values are correct, answer no and the system returns you to the ROMMON prompt. If you made any changes, the system reminds you that you must reset or power cycle the router before the new configuration register takes effect.

The following example shows how to set the configuration register to the typical value of 0x2102, so that it boots a Cisco IOS software image:


rommon 7 > confreg 0x2102
 
         You must reset or power cycle for new config to take effect.
rommon 8 > 

cont

To continue the execution of the Cisco IOS software image that has been interrupted by a BREAK signal or debugger breakpoint, use the cont command in ROM monitor mode.

cont [address]

Syntax Description

address

(Optional) Specifies the address in memory at which the router should continue execution. If address is not specified, the command continues execution at the address currently stored in the program counter (PC) register.

Caution

 

Do not use the address option unless instructed to do so by Cisco TAC engineers.

Command Default

If given without any arguments, the command continues execution at the address currently stored in the processor’s program counter (PC) register.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The cont command typically is used when a user has interrupted the operation of the Cisco IOS software by using the BREAK signal to enter ROM monitor mode, and then wants to continue with the original Cisco IOS software image. This command can also be used to continue program execution when the user uses the BREAK signal to interrupt the Cisco IOS software boot procedure, or has used the break command to set a debug breakpoint.

Examples

In the following example, the cont command continues executing the Cisco IOS software image, after the user has interrupted the software by sending a BREAK signal:


Router# 
telnet> send brk
*** System received an abort due to Break Key ***
signal= 0x3, code= 0x0, context= 0x6208b290
PC = 0x606b5ab0, SP = 0x80007e00, RA = 0x606d2370
Cause Reg = 0xffffffff, Status Reg = 0x3400ff03
rommon 5 > cont
 
Router# 

context

To display the processor context at the time of the most recent fault or exception, use the context command in ROM monitor mode.

context

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

When the processor fault or exception occurs, the ROM monitor preserves the processor context at the time of the fault. The context command displays this processor context, which includes information about the kernel registers and the process mode of the booted image (if available).

Examples

The following example shows how to display the CPU context at the time of the most recent fault or exception:


rommon 21 > context
 
Kernel Level Context:
 Reg       MSW        LSW     | Reg       MSW        LSW
------  ---------- ---------- | -----   ---------- ----------
zero   : 00000000   00000000  | s0     : ffffffff   80018a90
AT     : 00000000   00000050  | s1     : 00000000   00000002
v0     : ffffffff   fffffffc  | s2     : 00000000   00000006
v1     : 00000000   02000000  | s3     : ffffffff   80007798
a0     : ffffffff   80018a90  | s4     : 00000000   00000002
a1     : 00000000   00000002  | s5     : 00000000   000000ec
a2     : ffffffff   80007798  | s6     : 00000000   00000002
a3     : 00000000   00000002  | s7     : 00000000   00000000
t0     : ffffffff   ba000004  | t8     : ffffffff   800268b0
t1     : 00000000   00000002  | t9     : 00000000   00000000
t2     : 00000000   00000000  | k0     : 00000000   3040f001
t3     : 00000000   00000020  | k1     : ffffffff   be800014
t4     : 00000000   20642e31  | gp     : 00000000   60336f00
t5     : 00000000   30306153  | sp     : ffffffff   80007728
t6     : 00000000   446e7369  | s8     : 00000000   00000002
t7     : 00000000   206b4453  | ra     : ffffffff   80010570
HI     : 00000000   00000004  | LO     : 00000000   00007a2a
EPC    : ffffffff   80010250  | ErrPC  : ffffffff   bfc00c54
Stat   : 3040f003             | Cause  : 00008000
context: process context is not valid
rommon 22 > 

cpu_card_type

To display the type of processor card that is installed in the router, use the cpu_card_type command in ROM monitor mode.

cpu_card_type

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Examples

The following example shows that the router is using an NPE-225 processor card:


rommon 92 > cpu_card_type
 
CPU card type is NPE-225
rommon 93 > 

dev

To list the known storage and memory devices for the router, use the dev command in ROM monitor mode.

dev

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Examples

The following example shows how to display the known file systems on a router:


rommon 3 > dev 
Devices in device table:
        id  name
bootflash:  boot flash 
    slot0:  PCMCIA slot 0 
    slot1:  PCMCIA slot 1 
    disk0:  PCMCIA slot 0 
    disk1:  PCMCIA slot 1 
    disk2:  PCMCIA slot 2 
    eprom:  eprom 
rommon 4 > 

Note


The disk2 device is available only on a Cisco uBR7246VXR router using the NPE-G1 processor card.

dir

To list the files on one of the router’s file systems, use the dir command in ROM monitor mode.

dir device:

Syntax Description

device:

Specific device to be displayed.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Examples

The following example shows how to list the files on the slot0: and bootflash: devices.


rommon 40 > dir slot0:
 
         File size           Checksum   File name
        65 bytes (0x41)       0xb49d       basic.cm 
   2229799 bytes (0x220627)   0x469e       uBR7200-k.z

rommon 41 > dir bootflash:
 
         File size           Checksum   File name
   1378560 bytes (0x150900)   0x6607c732    ubr7200-kboot-mz.122.11.BC3
     16220 bytes (0x3f5c)     0x47e9a02c    bundle.cfg
        76 bytes (0x4c)       0x313b6bb0    config.cm
    189250 bytes (0x2e342)    0xe95da48e    crashinfo_20030515-212829
rommon 42 > 

dis

To disassemble a segment of main memory, use the dis command in ROM monitor mode.

dis [address] [num-of-bytes]

Syntax Description

address

(Optional) Address in main memory at which the disassembly should begin.

num-of-bytes

(Optional) Number of bytes to disassemble.

Command Default

If no arguments are given, the command prompts for the address and num-of-bytes parameters.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Examples

The following example shows a typical disassembly:


rommon 23 > dis 0x60696358 0x20 
0x60696358: 1040012b                beq v0, zero, #0x60696808
0x6069635c: 00008821                addu s1, zero, zero
0x60696360: 8e0285d0                lw v0, -31280(s0)
0x60696364: 14400006                bne v0, zero, #0x60696380
0x60696368: 00002021                addu a0, zero, zero
0x6069636c: 0c1a2d93                jal 0x6068b64c
0x60696370: 00002021                addu a0, zero, zero
0x60696374: 8e0285d0                lw v0, -31280(s0)
rommon 24 > 
The following example shows the command’s interactive mode being used to perform the same disassembly: 
rommon 25 > dis
 
Enter in hex the start address [0x0]:  0x60696358
 
Enter in hex the test size or length in bytes [0x0]:  0x20
 
0x60696358: 1040012b                beq v0, zero, #0x60696808
0x6069635c: 00008821                addu s1, zero, zero
0x60696360: 8e0285d0                lw v0, -31280(s0)
0x60696364: 14400006                bne v0, zero, #0x60696380
0x60696368: 00002021                addu a0, zero, zero
0x6069636c: 0c1a2d93                jal 0x6068b64c
0x60696370: 00002021                addu a0, zero, zero
0x60696374: 8e0285d0                lw v0, -31280(s0)
rommon 26 > 

The dis command displays an exception if you attempt to disassemble a non-existent address or if you specify an argument that the system interprets as a non-existent address. For example, the following command shows the dis disk0: command being given. The system interprets the disk0: argument as a memory address of 0xd, and because this address does not exist, displays the exception message:


rommon 3 > dis disk0:
 
Warning : address not word aligned, 0xd
*** TLB (Load/Fetch) Exception ***
Access address = 0xc
PC = 0xbfc11074, Cause Reg = 0x8, Status Reg = 0x3040d003
monitor: command "dis" aborted due to exception 
rommon 4 > 

frame

To display an individual stack frame, use the f rame command in ROM monitor mode.

frame [number]

Syntax Description

number

(Optional) Number of the stack frame to be displayed. The default is 0 (the most current frame).

Command Default

Displays stack frame 0.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The frame command displays a particular stack frame. Use the stack command to list the available stack frames and their frame numbers.

Examples

The following example shows the frame command being used to display the details of an individual frame displayed by the stack command:


rommon 5 > stack 6
 
Stack trace:
PC = 0x02004adc
Frame 00: FP = 0x02003938    RA = 0x02005f2a
Frame 01: FP = 0x02003948    RA = 0x02005df0
Frame 02: FP = 0x02003960    RA = 0x020050ee
Frame 03: FP = 0x02003994    RA = 0x02004034
Frame 04: FP = 0x02003b00    RA = 0x00012ca6
Frame 04: FP = 0x02003b34    RA = 0x020a703c
rommon 6 > frame 2
 
         Frame 02: FP = 0x02003960    RA = 0x020050ee
         at 0x02003968 (fp + 0x08) = 0x02004f8d
         at 0x0200396c (fp + 0x0c) = 0x0200f390
         at 0x02003970 (fp + 0x10) = 0x02006afc
         at 0x02003974 (fp + 0x14) = 0xc0a82983
         at 0x02003978 (fp + 0x18) = 0x02003a7e
         at 0x0200397c (fp + 0x1c) = 0x02002630
         at 0x02003980 (fp + 0x20) = 0x00000000
         at 0x02003984 (fp + 0x24) = 0x02000000
         at 0x02003988 (fp + 0x28) = 0x0200c4a4
         at 0x0200398c (fp + 0x2c) = 0x0200f448
rommon 7 > 

help

To display a short list of the commands that are available at the ROM monitor prompt, use the help command in ROM monitor mode.

help

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The help command displays a list of available ROM monitor commands, along with a brief description of each. To display additional details for a specific command, enter the command name followed by the -? option.

Examples

The following example shows a typical display of the help screen:


rommon 12 > help 
alias               set and display aliases command
boot                boot up an external process
break               set/show/clear the breakpoint
confreg             configuration register utility
cont                continue executing a downloaded image
context             display the context of a loaded image
cpu_card_type       display CPU card type
dev                 list the device table
dir                 list files in file system
dis                 disassemble instruction stream
frame               print out a selected stack frame
help                monitor builtin command help
history             monitor command history
meminfo             main memory information
repeat              repeat a monitor command
reset               system reset
set                 show all monitor variables
show_spd            show all SPD data
stack               produce a stack trace
sync                write monitor environment to NVRAM
sysret              print out info from last system return
unalias             unset an alias
unset               unset a monitor variable
rommon 13 > 

The following example shows how to display additional help for the alias command:


rommon 14 > alias -?
 
usage: alias [name=value]
rommon 15 > 

history

To display the last 16 commands given at the ROM monitor prompt, use the history command in ROM monitor mode.

history

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The ROM monitor keeps a record of the last commands given at the ROM monitor prompt (up to 16), similar to the way this is done with the Korn shell. Use the history command to display these commands, and the repeat command to repeat them one or more times.


Tip


When you use an alias , the history list includes the alias and not the actual commands that were executed.



Note


The repeat command is not added to the history list.

Examples

The following example shows how to reset the ROM monitor and return it to a known state:


rommon 9 > history
 
1   boot sysfiles/ubr10k-k8p6-mz.12211BC3 
2   dev 
3   dir disk0: 
4   confreg 
5   confreg 0x00 
6   cont 
7   break -c 
8   break 
9   history
rommon 10 > 

meminfo

To display information about the available range of main memory and Flash memory, use the meminfo command in ROM monitor mode.

meminfo

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The meminfo command displays the size of available main memory, its starting address, the size of available packet memory, and the size of nonvolatile Flash memory.

Examples

The following example shows how to display information about the current memory usage:


rommon 9 > meminfo
 
Main memory size: 512 MB.
Available main memory starts at 0xa000e000, size 0x7ffc8 KB
NVRAM size: 0x80000
rommon 10 > 

repeat

To repeat a particular ROM monitor command from the history list, use the repeat command in ROM monitor mode.

repeat [number [count] | string [count] ]

Syntax Description

number

(Optional) Specifies the number, as listed in the history command, of the command to be repeated.

string

(Optional) Specifies a string to be compared against the commands in the history list. The most recent command that matches the string is repeated. If the string includes spaces, it must be enclosed within quotes.

count

(Optional) Specifies the number of times the command should be executed. The default is 1.

Command Default

If given without any arguments, repeats the previous command once.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated nto Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The repeat command repeats one of the commands in the history list (which can contain up to 16 commands). You can specify the command to be repeated by its history number (as shown by the history command) or by a string that will match the command.

If you do not give any arguments with the command, it repeats the last command in the history list once.


Note


The repeat command is not added to the history list, so you cannot repeat the repeat command. You also cannot include the repeat command on a command line that has multiple commands separated by a semicolon delimiter.

Examples

The following example shows how to use the repeat command to execute one of the commands in the history list:


rommon 9 > history
 
1   boot sysfiles/ubr10k-k8p6-mz.12211BC3 
2   dev 
3   dir disk0: 
4   confreg 
5   confreg 0x00 
6   cont 
7   break -c 
8   break 
9   history
rommon 10 > repeat 9 
1   boot sysfiles/ubr10k-k8p6-mz.12211BC3 
2   dev 
3   dir disk0: 
4   confreg 
5   confreg 0x00 
6   cont 
7   break -c 
8   break 
9   history
10  history
rommon 11 > 

reset

To reinitialize the ROM monitor and return it to a known state, use the reset command in ROM monitor mode.

reset [-s]

Syntax Description

-s

(Optional) Saves the current environment (environment variables and aliases) to nonvolatile memory before performing the reset.

Command Default

If given without any arguments, resets all environment variables and aliases to their initialized states.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command ws integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The reset command returns the ROM monitor to its initial state, without requiring a complete system reboot by performing a warm reset. This is useful if you have been setting and unsetting registers and variables, and no longer know whether the system is in a stable state.

If you specify the -s option, the system saves the current environment variables and aliases to nonvolatile memory before resetting the ROM monitor, so as to preserve their current values.

Examples

The following example shows how to reset the ROM monitor and return it to a known state:


rommon 59 > reset
 
System Bootstrap, Version 12.0(9r)SL2, RELEASE SOFTWARE (fc1)
Copyright (c) 2000 by cisco Systems, Inc.
Reset Reason Register = RESET_REASON_RESET_REG (0x76)
C10000 platform with 524288 Kbytes of main memory
rommon 1 > 

set

To display the contents of the currently-defined environment variables, use the set command in ROM monitor mode.

set

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The set command displays the environment variables that are currently defined in the ROM monitor. Variables are defined at the ROM monitor prompt in a manner similar to that of the Korn shell, by specifying variable =value .


Tip


Use the unset command to delete a monitor variable.


Examples

The following example shows how to display the values of the currently defined monitor variables:


rommon 13 > set
 
PS1=rommon ! > 
RET_2_RTS=17:28:46 PST Tue Oct 12 1993
BSI=0
RET_2_RUTC=
?=1 
rommon 14 > 

The following example shows the PS1 variable (which defines the ROM monitor prompt) being changed, and the set command displaying the new value:


rommon 12 > PS1=”Rommon-CMTS ! >”
 
Rommon-CMTS 13 > set
 
PS1=Rommon-CMTS ! > 
RET_2_RTS=17:28:46 PST Tue Oct 12 1993
BSI=0
RET_2_RUTC=
?=1 
Rommon-CMTS 14 > 

show_spd

To display the contents of the processor’s Serial Presence Detect (SPD) device (an electrically erasable programmable read-only memory (EEPROM) device), use the show_spd command in ROM monitor mode.

show_spd

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The show_spd command displays the contents of the processor card’s SPD/EEPROM memory device. This information is typically useful only to Cisco TAC engineers.


Note


The show_spd command displays a large volume of data. Enable the capture buffer on your terminal program so that you can preserve this data and review it later.

Examples

The following example shows how to display the SPD data (only a portion of the command’s display is shown):


rommon 15 > show_spd
 
DIMM 0 SPD specifications:
byte 0 - 0x80000000
byte 1 - 0x8000000
byte 2 - 0x4000000
...
byte 125 - 0xff000000
byte 126 - 0x64000000
byte 127 - 0xad000000
DIMM 1 SPD specifications:
byte 0 - 0xff000000
byte 1 - 0xff000000
byte 2 - 0xff000000
...
byte 125 - 0xff000000
byte 126 - 0xff000000
byte 127 - 0xff000000
DIMM 2 SPD specifications:
byte 0 - 0xff000000
byte 1 - 0xff000000
byte 2 - 0xff000000
...
byte 125 - 0xff000000
byte 126 - 0xff000000
byte 127 - 0xff000000
DIMM 3 SPD specifications:
byte 0 - 0xff000000
byte 1 - 0xff000000
byte 2 - 0xff000000
...
byte 125 - 0xff000000
byte 126 - 0xff000000
byte 127 - 0xff000000
DIMM 0: Tclk cycle time = 12, Tac access from clk = 7
DIMM 0: Trp precharge = 20
DIMM 0: Trcd RAS to CAS = 20
DIMM 1: Tclk cycle time = 15, Tac access from clk = 15
DIMM 1: Tclk = 15 may NOT support CL = 2
DIMM 1: Tac = 15 may NOT support CL = 2
DIMM 1: Trp precharge = 255
DIMM 1: Trp = 255 CANNOT support SRASPrchg = 2
DIMM 1: Trcd RAS to CAS = 255
DIMM 1: Trcd = 255 CANNOT support SRAStoSCAS = 2
DIMM 2: Tclk cycle time = 15, Tac access from clk = 15
DIMM 2: Tclk = 15 may NOT support CL = 2
DIMM 2: Tac = 15 may NOT support CL = 2
DIMM 2: Trp precharge = 255
DIMM 2: Trp = 255 CANNOT support SRASPrchg = 2
DIMM 2: Trcd RAS to CAS = 255
DIMM 2: Trcd = 255 CANNOT support SRAStoSCAS = 2
DIMM 3: Tclk cycle time = 15, Tac access from clk = 15
DIMM 3: Tclk = 15 may NOT support CL = 2
DIMM 3: Tac = 15 may NOT support CL = 2
DIMM 3: Trp precharge = 255
DIMM 3: Trp = 255 CANNOT support SRASPrchg = 2
DIMM 3: Trcd RAS to CAS = 255
DIMM 3: Trcd = 255 CANNOT support SRAStoSCAS = 2
rommon 16 > 

stack

To display a stack trace, use the stack command in ROM monitor mode.

stack [number]

Syntax Description

number

(Optional) Number of stack frames to display. The default is 5 frames.

Command Default

Displays 5 stack frames

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The stack command displays a stack trace of the most recently booted software image. This trace includes the value of the program counter and the selected number of frames from the kernel stack and process stack (if available) from that software image.


Tip


To display details for an individual frame stack, use the frame command.


Examples

The following example shows how to display a stack trace with 6 frames:


rommon 5 > stack 6
 
Stack trace:
PC = 0x02004adc
Frame 00: FP = 0x02003938    RA = 0x02005f2a
Frame 01: FP = 0x02003948    RA = 0x02005df0
Frame 02: FP = 0x02003960    RA = 0x020050ee
Frame 03: FP = 0x02003994    RA = 0x02004034
Frame 04: FP = 0x02003b00    RA = 0x00012ca6
Frame 04: FP = 0x02003b34    RA = 0x020a703c
rommon 6 > 

The following example shows how to display a stack trace with the default of 5 frames, when a process stack is available:


rommon 21 > stack
   
Kernel Level Stack Trace:
Initial SP = 0x61bb4d30, Initial PC = 0x606931b0, RA = 0x6067bca0
Frame 0 : FP= 0x61bb4d30, PC= 0x606931b0,   0 bytes
Frame 1 : FP= 0x61bb4d30, PC= 0x6067bca0,  24 bytes
Frame 2 : FP= 0x61bb4d48, PC= 0x6068db30,  48 bytes
Frame 3 : FP= 0x61bb4d78, PC= 0x6069157c,  32 bytes
Frame 4 : FP= 0x61bb4d98, PC= 0x606905e0,  88 bytes
Process Level Stack Trace:
Initial SP = 0x80007e08, Initial PC = 0x60696358, RA = 0x60699080
Frame 0 : FP= 0x80007e08, PC= 0x60696358, 192 bytes
Frame 1 : FP= 0x80007ec8, PC= 0x606939d0,  56 bytes
Frame 2 : FP= 0x80007f00, PC= 0x60008c94,  32 bytes
Frame 3 : FP= 0x80007f20, PC= 0x80008ae0,  32 bytes
Frame 4 : FP= 0x80007f40, PC= 0x80008840, 128 bytes
rommon 22 > 

sync

To write the current values of aliases and monitor environment variables to Flash memory, use the sync command in ROM monitor mode.

sync

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The sync command writes the current values of the monitor environment variables and aliases to Flash memory so that they are read on the next reset. If you do not do this, all variables and aliases are deleted upon reset and replaced with the default values.

Examples

The following example shows how to synchronize the monitor variables and aliases:


rommon 39 > sync
 
rommon 40 > 

sysreset

To display information about the system image that was last booted, use the sysreset command in ROM monitor mode.

sysreset

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The sysreset command displays the information about the last system image that was booted and then terminated. This includes the reason for why the last image ended its execution, the values of the program counter and error address registers when the program ended execution, and a stack trace holding the last eight frames. Any exception information is also shown.

Examples

The following example shows a typical display from the sysreset command:


rommon 22 > sysreset
 
System Return Info:
count: 19,  reason: user reload
pc:0x6053059c,  error address: 0x0
Stack Trace:
FP: 0x6558b0d0, PC: 0x6053059c
FP: 0x6558b0d0, PC: 0x605163a4
FP: 0x6558b0e8, PC: 0x60535b84
FP: 0x6558b170, PC: 0x60488c50
FP: 0x6558b268, PC: 0x60474aa8
FP: 0x6558b2c8, PC: 0x6014d5d0
FP: 0x6558b2e8, PC: 0x60487928
FP: 0x6558b378, PC: 0x604fe80c
rommon 23 > 

unalias

To delete a currently-defined alias, use the unalias command in ROM monitor mode.

unalias name [name2 name3 . . . ]

Syntax Description

name

Specifies the alias to be deleted.

name2 name3 ...

(Optional) Specifies additional aliases to be deleted.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The unalias command deletes one or more aliases that you have previously defined for the ROM monitor using the alias command.

Examples

The following example shows how to delete one alias:


rommon 13 > unalias dird 
rommon 14 > 

The following example shows three aliases being deleted:


rommon 20 > unalias alias1 alias2 alias3
 
rommon 21 > 

The following example shows the error message that is displayed when you try to delete an alias that does not exist:


rommon 11 > unalias gobbledegook
 
unalias: "gobbledegook" does not exist
rommon 12> 

unset

To delete the current contents of a monitor environment variable, use the unset command in ROM monitor mode.

unset name [name2 name3 . . . ]

Syntax Description

name

Specifies the variable to be cleared.

name2 name3 ...

(Optional) Specifies additional variables to be cleared.

Command Default

No default behavior or values.

Command Modes


ROM monitor (>)

Command History

Release

Modification

11.3 NA

This command was introduced on Cisco uBR7200 series routers.

12.1(5)EC

Support was added for Cisco uBR7100 series routers.

12.2(4)BC1

Support was added for the Cisco uBR10012 router. Changes were also made to the boot procedure after breaking into ROMMON to ensure that all hardware and software registers are in a known state before loading the new image.

12.3BC

This command was integrated into Cisco IOS Release 12.3BC.

12.2(33)SCA

This command was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR router was added.

Usage Guidelines

The unset command clears the contents of one or more monitor variables that have been defined in the ROM monitor. Variables are defined at the ROM monitor prompt in a manner similar to that of the Korn shell, by specifying variable =value .

Examples

The following example shows how to delete a variable named “temp-var”:


rommon 13 > unset temp-var
 
rommon 14 > 

The following example shows how to delete two variables:


rommon 17 > unset temp-var my-var
 
rommon 18 >