====== 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 [[:scripting|script]].

===== Command status =====

^ Failure   | The label does not exist |

It is logically impossible for this command to return successfully.

===== See also =====

  * ''[[:cmd:inc]]''
  * ''[[:cmd:isset]]''
  * ''[[:cmd:iseq]]''
  * ''[[:cmd:exit]]''
  * iPXE [[:scripting|scripting]] guide
  * [[:cmd|List of all iPXE commands]]

===== 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 ''[[:cmd:dhcp]]'' command fails, then the script will immediately terminate, as described in the [[:scripting#error_handling|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 ''[[:cmd:inc]]'' and ''[[:cmd:iseq]]'' commands.