How to stop a PowerShell script on the first error

Question

I want my PowerShell script to stop when any of the commands I run fail  like set -e in bash   I m using both Powershell commands  New-Object System Net WebClient  and programs    setup exe

User · Answer

Redirecting stderr to stdout seems to also do the trick without any other commands scriptblock wrappers although I can t find an explanation why it works that way      test ps1   ErrorActionPreference    Stop   aws s3 ls s3   xxx echo     gt  pass   aws s3 ls s3   xxx 2 gt  amp 1 echo  shouldn t be here    This will output the following as expected  the command aws s3     returns  LASTEXITCODE   255   PS gt    test ps1  An error occurred  AccessDenied  when calling the ListObjectsV2 operation  Access Denied    gt  pass

User · Answer

I came here looking for the same thing    ErrorActionPreference  Stop  kills my shell immediately when I d rather see the error message  pause  before it terminates   Falling back on my batch sensibilities   IF  ERRORLEVEL  NEQ 0 pause  amp  GOTO EOF   I found that this works pretty much the same for my particular ps1 script   Import-PSSession  Session If     -ne  True    Pause  Exit

User · Answer

You need slightly different error handling for powershell functions and for calling exe s  and you need to be sure to tell the caller of your script that it has failed  Building on top of Exec from the library Psake  a script that has the structure below will stop on all errors  and is usable as a base template for most scripts   Set-StrictMode -Version latest  ErrorActionPreference    Stop      Taken from psake https   github com psake psake  lt    SYNOPSIS   This is a helper function that runs a scriptblock and checks the PS variable  lastexitcode   to see if an error occcured  If an error is detected then an exception is thrown    This function allows you to run command-line programs without having to   explicitly check the  lastexitcode variable   EXAMPLE   exec   svn info  repository trunk    Error executing SVN  Please verify SVN command-line client is installed    gt  function Exec        CmdletBinding        param           Parameter Position 0 Mandatory 1   scriptblock  cmd           Parameter Position 1 Mandatory 0   string  errorMessage     Error executing command  0   -f  cmd             amp   cmd     if   lastexitcode -ne 0            throw   Exec       errorMessage           Try          Put all your stuff inside here         powershell functions called as normal and try  catch reports errors      New-Object System Net WebClient        call exe s and check their exit code using Exec     Exec   setup exe      Catch         tell the caller it has all gone wrong      host SetShouldExit -1      throw

User · Answer

I m new to powershell but this seems to be most effective   doSomething -arg myArg if  -not      throw  Failed to doSomething

User · Answer

A slight modification to the answer from  alastairtree   function Invoke-Call       param            scriptblock  ScriptBlock           string  ErrorAction    ErrorActionPreference            amp   ScriptBlock     if    lastexitcode -ne 0  -and  ErrorAction -eq  Stop             exit  lastexitcode          Invoke-Call -ScriptBlock   dotnet build     -ErrorAction Stop   The key differences here are    it uses the Verb-Noun  mimicing Invoke-Command  implies that it uses the call operator under the covers mimics -ErrorAction behavior from built in cmdlets exits with same exit code rather than throwing exception with new message

User · Answer

Sadly  due to buggy cmdlets like New-RegKey and Clear-Disk  none of these answers are enough  I ve currently settled on the following code in a file called ps support ps1  Set-StrictMode -Version Latest  ErrorActionPreference    quot Stop quot   PSDefaultParameterValues    ErrorAction    Stop  function ThrowOnNativeFailure       if  -not                   throw  Native Failure           Then in any powershell file  after the CmdletBinding and Param for the file  if present   I have the following   ErrorActionPreference    quot Stop quot     quot  PSScriptRoot ps support ps1 quot   The duplicated ErrorActionPreference    quot Stop quot  line is intentional  If I ve goofed and somehow gotten the path to ps support ps1 wrong  that needs to not silently fail  I keep ps support ps1 in a common location for my repo workspace  so the path to it for the dot-sourcing may change depending on where the current  ps1 file is  Any native call gets this treatment  native call exe ThrowOnNativeFailure  Having that file to dot-source has helped me maintain my sanity while writing powershell scripts   -

User · Answer

ErrorActionPreference    Stop  will get you part of the way there  i e  this works great for cmdlets    However for EXEs you re going to need to check  LastExitCode yourself after every exe invocation and determine whether that failed or not  Unfortunately I don t think PowerShell can help here because on Windows  EXEs aren t terribly consistent on what constitutes a  success  or  failure  exit code   Most follow the UNIX standard of 0 indicating success but not all do  Check out the CheckLastExitCode function in this blog post  You might find it useful

User · Answer

You should be able to accomplish this by using the statement  ErrorActionPreference    Stop  at the beginning of your scripts   The default setting of  ErrorActionPreference is Continue  which is why you are seeing your scripts keep going after errors occur

[windows] How to stop a PowerShell script on the first error?

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