Jump to script label

Synopsis

  goto <label>

Examples

Print "hello world" indefinitely

  :loop
  echo Hello world
  goto loop

Jump to a calculated label

  goto host_${hostname} || goto unknown

Description

Jump to a script label. This command can be used only within an iPXE script.

Command status

Failure The label does not exist

It is logically impossible for this command to return successfully.

See also

Notes

If you are using goto to jump to a label when an operation succeeds, then you must also consider what would happen if the operation were to fail. For example:

  dhcp && goto dhcp_ok

If the dhcp command fails, then the script will immediately terminate, as described in the scripting guide. To avoid this problem, you can use the || operator:

  dhcp && goto dhcp_ok ||

As with all iPXE commands, any settings such as ${hostname} will be expanded. It is therefore possible to use a dynamically-generated label as the target for the goto command. For example, if the hostname provided by DHCP is thinclient1, then the command

  goto host_${hostname}

would jump to the label host_thinclient1.

When using dynamically-generated labels, it is generally a good idea to include a fallback label in case the dynamically-generated label does not exist. For example:

 #!ipxe
 
 dhcp
 goto host_${hostname} || goto unknown
 
 :host_thinclient1
 sanboot iscsi:192.168.0.1::::iqn.2010-04.org.ipxe:winxp
 
 :host_thinclient2
 sanboot iscsi:192.168.0.1::::iqn.2010-04.org.ipxe:win7
 
 :unknown
 echo Unknown host ${hostname}

You can construct simple loops using the inc and iseq commands.

 
cmd/goto.txt · Last modified: 2013/08/01 14:21 by mcb30
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