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Laurence MorganAbout 2 min


Events triggered by changes in state of the interactive shell


onPrompt events are triggered by changes in state of the interactive shell (often referred to as readline). Those states are defined in the interrupts section below.


event onPrompt name=(before|after|abort|eof) { code block }

!event onPrompt [before_|after_|abort_|eof_]name

Valid Interrupts

  • abort Triggered if ctrl+c pressed while in the interactive prompt
  • after Triggered after user has written a command into the interactive prompt and then hit enter
  • before Triggered before readline displays the interactive prompt
  • eof Triggered if ctrl+d pressed while in the interactive prompt


The following payload is passed to the function via STDIN:

    "Name": "",
    "Interrupt": {
        "Name": "",
        "Operation": "",
        "CmdLine": ""


This is the namespaced name -- ie the name and operation.


This is the name you specified when defining the event.


This is the interrupt you specified when defining the event.

Valid interrupt operation values are specified below.


This is the commandline you typed in the prompt.

Please note this is only populated if the interrupt is after.


Interrupt 'before':

event onPrompt example=before {
    out "This will appear before your command prompt"

Interrupt 'after':

event onPrompt example=after {
    out "This will appear after you've hit [enter] on your command prompt"
    out "...but before the command executes"

Echo the command line:

» event onPrompt echo=after { -> set event; out $event.Interrupt.CmdLine }
» echo hello world
echo hello world
hello world



Stdout is written to the terminal. So this can be used to provide multiple additional lines to the prompt since readline only supports one line for the prompt itself and three extra lines for the hint text.

Order of execution

Interrupts are run in alphabetical order. So an event named "alfa" would run before an event named "zulu". If you are writing multiple events and the order of execution matters, then you can prefix the names with a number, eg 10_jump


The onPrompt event differs a little from other events when it comes to the namespacing of interrupts. Typically you cannot have multiple interrupts with the same name for an event. However with onPrompt their names are further namespaced by the interrupt name. In layman's terms this means example=before wouldn't overwrite example=after.

The reason for this namespacing is because, unlike other events, you might legitimately want the same name for different interrupts (eg a smart prompt that has elements triggered from different interrupts).

See Also

This document was generated from builtins/events/onPrompt/onprompt_doc.yamlopen in new window.

Last update:
Contributors: Laurence Morgan