Question

After writing deployment scripts from within the ISE, we need our continuous integration (CI) server to be able to run them automatically, i.e. from the command line or via a batch file.

I have noticed some significant differences between the following calls:

powershell.exe -File Script.ps1
powershell.exe -Command "& '.\Script.ps1'"
powershell.exe .\Script.ps1

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Some simple examples:

• When using -File, errors are handled in the exact same way as the ISE.
• The other two calls seem to ignore the $ErrorActionPreference variable, and do not catch Write-Error in try/catch blocks.

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When using pSake:

• The last two calls work perfectly
• Using the ISE or the -File parameter will fail with the following error:

The variable '$script:context' cannot be retrieved because it has not been set

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What are the implications of each syntax, and why they are behaving differently? I would ideally like to find a syntax that works all the time and behaves like the ISE.

Answer 1

Not an answer, just a note.

I searched for explanation of -file parameter. Most sources say only “Execute a script file.”. At http://technet.microsoft.com/en-us/library/dd315276.aspx I read

Runs the specified script in the local scope ("dot-sourced"), so that the functions
and variables that the script creates are available in the current session. Enter
the script file path and any parameters.

After that I tried to call this:

powershell -command ". c:\temp\aa\script.ps1"
powershell -file c:\temp\aa\script.ps1
powershell -command "& c:\temp\aa\script.ps1"

Note that first two stop after Get-Foo, but the last one doesn’t.

The problem I describe above is related to modules — if you define Get-Foo inside script.ps1, all the 3 calls I described stop after call to Get-Foo.

Just try to define it inside the script.ps1 or dotsource the file with Get-Foo and check it. There is a chance it will work 🙂