Prompt user to press key

  prompt [--key <key>] [--timeout <timeout>] [<text>]

  prompt

  prompt Press any key to continue

  prompt --key q Press 'q' to quit && exit ||

  prompt --key 0x197e --timeout 2000 Press F12 to boot from network... || exit

  prompt --key 0x02 --timeout 2000 Press Ctrl-B for the iPXE command line... && shell ||

Prompt the user to press a key, displaying the specified text and waiting for the specified timeout (in milliseconds). If no timeout is explicitly specified, or if a zero timeout is specified, then iPXE will wait indefinitely.

The command status will be successful if the specified key was pressed. If no key was explicitly specified, then the command will be successful if any key was pressed.

The displayed text will be cleared when the user presses a key, or if the timeout expires.

The --key option can be specified as a character literal (such as q or @) or as an extended ASCII character value. The values for special keys such as Ctrl-B and F12 are defined in include/ipxe/keys.h within the iPXE source code. Some useful values are:

• echo
• iPXE scripting guide
• List of all iPXE commands

To prevent the prompt command from causing your script to exit, you will almost always want to use the || operator. For example, do not use a line such as

  prompt --timeout 1000 Press any key to install Linux && goto install

If the user does not press a key, then the prompt command will fail and will cause your script to exit immediately. You can avoid this problem by using the || operator to ensure that the failure of the prompt command is handled appropriately. For example:

  prompt --timeout 1000 Press any key to install Linux && goto install || goto no_install

or

  prompt --timeout 1000 Press any key to install Linux && goto install ||

See the iPXE scripting guide for further information on the && and || operators.

When you use an embedded script, you will no longer see the “Press Ctrl-B for the iPXE command line” prompt at startup or if booting fails. You can generate your own prompt using the prompt command. For example:

  #!ipxe
  
  # Give user a chance to enter the shell
  prompt --key 0x02 --timeout 2000 Press Ctrl-B for the iPXE shell... || goto no_shell
  shell
  exit
  
  :no_shell
  # Boot the system
  ...