Loading custom functions in PowerShell

Question

I've got some additional functions that I've defined in an additional PowerShell script file, that I'm trying to load in a main .ps1 file. However, when I call the .ps1 file from the PowerShell prompt it doesn't seem to run through those commands.

In the following code example, build_functions.ps1 has code that defines various custom functions. If I run the file separately (for example, running it by itself and then running through the primary script) it works fine. Build_builddefs.ps1 contains a number of variables that also need to be populated prior to running the primary script.

At the beginning of my primary script I have this:

.\build_functions.ps1
.\build_builddefs.ps1

However, these don't seem to be run, because the primary script fails when it tries to execute the first custom function. What am I doing wrong?

Nice link on loading functions at PS startup: sandfeld.net/powershell-load-your-functions-at-startup — Andrew
– Andrew, Commented Mar 16, 2018 at 14:25

bryanbcook · Accepted Answer · 2020-06-05 14:49:38Z

74

You have to dot source them:

. .\build_funtions.ps1
. .\build_builddefs.ps1

Note the extra .

This heyscriptingguy article should be of help - How to Reuse Windows PowerShell Functions in Scripts

edited Jun 5, 2020 at 14:49

bryanbcook

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answered Sep 12, 2013 at 12:31

manojlds

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3 Comments

Timo Over a year ago

If I do not know the source path, how can I find out?

melMass Over a year ago

@Timo check my answer ;)

L_7337 Over a year ago

Also, you can run dir function: after that to make sure the function got loaded.

Rohin Sidharth · Accepted Answer · 2016-04-21 03:11:53Z

46

I kept using this all this time

Import-module .\build_functions.ps1 -Force

answered Apr 21, 2016 at 3:11

Rohin Sidharth

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2 Comments

Frank Fu Over a year ago

I prefer this answer to @manojlds because dot sourcing doesn't allow a user to "undo" the dot sourcing. With Import-Module you can easily remove the module by Remove-Module Build_Functions

mklement0 Over a year ago

It's best to avoid using Import-Module with regular .ps1 scripts (as opposed to .psm1 files, which are true modules), because it can create conceptual confusion. In effect, Import-module .\build_functions.ps1 -Force is the same as . .\build_functions.ps1 - simple dot-sourcing, no actual modules involved (except for a pseudo module showing up in Get-Module output). Therefore, @FrankFu, you can not use Remove-Module to unload such definitions later - see this answer for details.

E_net4 · Accepted Answer · 2022-05-16 08:59:05Z

2

KERR's answer is IMO the only "valid" one. Relative paths given like in most answers won't resolve from the script's path but from PWD...

Here is how to load relative files:

$parent_dir = Split-Path $MyInvocation.MyCommand.Path

. $parent_dir\Scripts\prompt.ps1
. $parent_dir\Scripts\aliases.ps1
. $parent_dir\Scripts\isoTools.ps1

You can find more informations about Automatic Variable here

edited May 16, 2022 at 8:59

E_net4

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answered May 15, 2022 at 13:44

melMass

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Comments

KERR · Accepted Answer · 2021-11-10 00:52:19Z

0

Here's how to load one from a specific path/directory:

. "C:\scripts\Function-Search-AD.ps1"

answered Nov 10, 2021 at 0:52

KERR

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