In PowerShell how do I define a function in a file and call it from the PowerShell commandline

Question

I have a  ps1 file in which I want to define custom functions   Imagine the file is called MyFunctions ps1  and the content is as follows   Write-Host  Installing functions  function A1       Write-Host  A1 is running     Write-Host  Done    To run this script and theoretically register the A1 function  I navigate to the folder in which the  ps1 file resides and run the file     MyFunctions ps1   This outputs   Installing functions Done   Yet  when I try to call A1  I simply get the error stating that there is no command function by that name   The term  A1  is not recognized as the name of a cmdlet  function  script file  or operable program  Check the spelling  of the name  or if a path was included  verify that the path is correct and try again  At line 1 char 3   A1  lt  lt  lt  lt        CategoryInfo            ObjectNotFound   A1 String      CommandNotFoundException       FullyQualifiedErrorId   CommandNotFoundException   I must misunderstand some PowerShell concepts  Can I not define functions in script files   Note that I have already set my execution policy to  RemoteSigned   And I know to run  ps1 files using a dot in front of the file name    myFile ps1

User · Accepted Answer

Try this on the PowerShell command line       MyFunctions ps1 A1   The dot operator is used for script include

User · Answer

You certainly can define functions in script files  I then tend to load them through my Powershell profile on load    First you need to check to make sure the function is loaded by running   ls function     where      Name -eq  A1       And check that it appears in the list  should be a list of 1    then let us know what output you get

User · Answer

What you are talking about is called dot sourcing  And it s evil  But no worries  there is a better and easier way to do what you are wanting with modules  it sounds way scarier than it is   The major benefit of using modules is that you can unload them from the shell if you need to  and it keeps the variables in the functions from creeping into the shell  once you dot source a function file  try calling one of the variables from a function in the shell  and you ll see what I mean    So first  rename the  ps1 file that has all your functions in it to MyFunctions psm1  you ve just created a module    Now for a module to load properly  you have to do some specific things with the file  First for Import-Module to see the module  you use this cmdlet to load the module into the shell   it has to be in a specific location  The default path to the modules folder is  home Documents WindowsPowerShell Modules   In that folder  create a folder named MyFunctions  and place the MyFunctions psm1 file into it  the module file must reside in a folder with exactly the same name as the PSM1 file    Once that is done  open PowerShell  and run this command   Get-Module -listavailable   If you see one called MyFunctions  you did it right  and your module is ready to be loaded  this is just to ensure that this is set up right  you only have to do this once    To use the module  type the following in the shell  or put this line in your  profile  or put this as the first line in a script    Import-Module MyFunctions   You can now run your functions  The cool thing about this is that once you have 10-15 functions in there  you re going to forget the name of a couple  If you have them in a module  you can run the following command to get a list of all the functions in your module   Get-Command -module MyFunctions   It s pretty sweet  and the tiny bit of effort that it takes to set up on the front side is WAY worth it

User · Answer

If your file has only one main function that you want to call expose  then you can also just start the file with   Param  Param1    You can then call it e g  as follows     MyFunctions ps1 -Param1  value1    This makes it much more convenient if you want to easily call just that function without having to import the function

User · Answer

You can add function to   c  Users David Documents WindowsPowerShell profile ps1   An the function will be available

User · Answer

PSScriptRoot MyFunctions ps1  MyA1Func  Availalbe starting in v3  before that see How can I get the file system location of a PowerShell script    It is VERY common     P S  I don t subscribe to the  everything is a module  rule   My scripts are used by other developers out of GIT  so I don t like to put stuff in specific a place or modify system environment variables before my script will run   It s just a script  or two  or three

User · Answer

Assuming you have a module file called Dummy-Name psm1 which has a method called Function-Dumb       Import-Module  Dummy-Name psm1   Get-Command -Module  Function-Dumb       Function-Dumb

[powershell] In PowerShell, how do I define a function in a file and call it from the PowerShell commandline?

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