Recently I've started fiddling around with PowerShell, and I bumped into an issue with running .jar files. Simply put, I'm using plantuml and I'd like to simply have a "plantuml" command to run it. Normally, running the program would be done by typing. java -jar C:\Users\Name\Documents\WindowsPowerShell\Commands\plantuml.jar. This is of course quite a handful, and I'd like to shorten this to simply plantuml.
My current work-around is the following function:
function plantuml($UmlPath, $ImgPath) {
java -jar C:\Users\Name\Documents\WindowsPowerShell\Commands\plantuml.jar $UmlPath $ImgPath
}
However, I cannot pass any parameters to the .jar file like this, because Powershell intercepts them and interprets them as function parameters. A current workaround for this is by wrapping them in quotation marks, but I find this ugly and I often forget.
Is there any way to simply be able to type plantuml so that PowerShell expands it to java -jar C:\Users\Name\Documents\WindowsPowerShell\Commands\plantuml.jar? The only similar question I found was this one, but it doesn't appear to have an actual answer.
I don't have plantuml or anything similar to test with, but you can get all the parameters passed to a function with the $args variable, so this approach might work:
function plantuml {
# Array of your default arguments to Java.exe to start plantuml
$arguments = #('-jar',
'C:\Users\Name\Documents\WindowsPowerShell\Commands\plantuml.jar')
# All arguments passed to this function, umlpath, imgpath, and anything else
# are in the special variable $args, add those into the array as well.
$arguments += $args
Start-Process Java -ArgumentList $arguments
}
Related
There's a few commands I need to run repetitively in Powershell, with some variable arguments in content and length, but some arguments must always be there. I don't want to forget those arguments, so is there a way to create a function that does this?
I have tried using things like Invoke-Expression, but when I use brackets in a command, Powershell thinks it's a type and tells me my cast is not valid. If I escape the argument list and provide an argument in the form Key=Value, PowerShell parses it into a System.Object[] and the command fails. I figured it might be better not to ask about how to fix that, but how to solve my root problem.
You can consider this a somewhat duplicate of How to always append an ampersand for certain commands? (MacOS / bash) but for PowerShell.
Just write your own version of the command as a Function with mandatory parameters:
Function RunMyCommand {
Param(
[Parameter(Position=0,mandatory=$true)][string]$Argument1,
[Parameter(Position=1,mandatory=$true)][int]$Argument2,
[Parameter(Position=2,mandatory=$true)]$Argument3
)
# Amend this according to the syntax and string manipulation required for your command
ThisIsMyCommand $Argument1 $Argument2 $Argument3
}
RunMyCommand -Argument1 ThisString -Argument2 ThisNumber -Argument3 ThisAnything
I know I can dot source a file:
. .\MyFunctions.ps1
But, I would like to dot source the commands in a string variable:
. $myFuctions
I see that this is possible:
.{$x=2}
And $x equals 2 after the script block is sourced.
But... .{$myFunctions} does not work.
I tried $myFunctions | Invoke-Expression, but it doesn't keep the source function in the current scope. The closest I have been able to come up with is to write the variable to a temporary file, dot source the file, and then remove the file.
Inevitably, someone will ask: "What are you trying to do?" So here is my use case:
I want to obfuscate some functions I intend to call from another script. I don't want to obfuscate the master script, just my additional functions. I have a user base that will need to adjust the master script to their network, directory structure and other local factors, but I don't want certain functions modified. I would also like to protect the source code. So, an alternate question would be: What are some good ways to protect PowerShell script code?
I started with the idea that PowerShell will execute a Base64-encoded string, but only when passed on the command line with -EncodedCommand.
I first wanted to dot source an encoded command, but I couldn't figure that out. I then decided that it would be "obfuscated" enough for my purposes if I converted by Base64 file into a decode string and dot sourced the value of the string variable. However, without writing the decoded source to a file, I cannot figure out how to dot source it.
It would satisfy my needs if I could Import-Module -EncodedCommand .\MyEncodedFile.dat
Actually, there is a way to achieve that and you were almost there.
First, as you already stated, the source or dot operator works either by providing a path (as string) or a script block. See also: . (source or dot operator).
So, when trying to dot-source a string variable, PowerShell thinks it is a path. But, thanks to the possibility of dot-sourcing script blocks, you could do the following:
# Make sure everything is properly escaped.
$MyFunctions = "function Test-DotSourcing { Write-Host `"Worked`" }"
. { Invoke-Expression $MyFunctions }
Test-DotSourcing
And you successfully dot-sourced your functions from a string variable!
Explanation:
With Invoke-Expression the string is evaluated and run in the child scope (script block).
Then with . the evaluated expressions are added to the current scope.
See also:
Invoke-Expression
About scopes
While #dwettstein's answer is a viable approach using Invoke-Expression to handle the fact that the function is stored as a string, there are other approaches that seem to achieve the same result below.
One thing I'm not crystal clear on is the scoping itself, Invoke-Expression doesn't create a new scope so there isn't exactly a need to dot source at that point...
#Define your function as a string
PS> $MyUselessFunction = "function Test-WriteSomething { 'It works!' }"
#Invoke-Expression would let you use the function
PS> Invoke-Expression $MyUselessFunction
PS> Test-WriteSomething
It works!
#Dot sourcing works fine if you use a script block
PS> $ScriptBlock = [ScriptBlock]::Create($MyUselessFunction)
PS> . $ScriptBlock
PS> Test-WriteSomething
It works!
#Or just create the function as a script block initially
PS> $MyUselessFunction = {function Test-WriteSomething { 'It works!' }}
PS> . $MyUselessFunction
PS> Test-WriteSomething
It works!
In other words, there are probably a myriad of ways to get something similar to what you want - some of them documented, and some of them divined from the existing documentation. If your functions are defined as strings, then Invoke-Expression might be needed, or you can convert them into script blocks and dot source them.
At this time it is not possible to dot source a string variable.
I stand corrected! . { Invoke-Expression $MyFunctions } definitely works!
I have little experience with PowerShell in particular.
I'm trying to refactor some very commonly re-used code into a single script that can be sourced where it's needed, instead of copying and pasting this same code into n different scripts.
The scenario I'm trying to get looks (I think) like this:
#common.ps1:
param(
# Sure'd be great if clients didn't need to know about these
$some_params_here
...
)
function Common-Func-Uses-Params {
...
}
⋮
# foo/bar/bat.ps1:
# sure would love not to have to redefine all the common params() here...
. common.ps1 <pass-the-arguments>
Common-Func-Uses-Params $specific_Foo/Bar/Bat_Data
As the pseudo-comments above indicate, I've only been able to do this so far by capturing the params in the calling script as well.
I want to be in a situation where I can update the common code (say with a -Debug or -DryRun or -Url or whatever parameter) and not have to worry about updating all of the client code to match.
Is this possible?
You're missing two key things:
args - which captures all of (and only) the unbound arguments to the script
splatting (#) - which is used to pass arrays or hashtables to a command rather than flattening them like you'd get with $
When you combine these, you can easily pass all arguments onto another script, like so:
# foo.ps1
. common.ps1 #args
With a sourced file like this:
#common.ps1
param ([string]$foo = "foo")
echo "`$foo is $foo"
You get these output:
> foo.ps1 returns $foo is foo
> foo.ps1 -Foo bar returns $foo is bar
Note that, if you're trying to use the PowerShell ISE it might take you a while to figure this out or debug any of it. When you're in the debugger, both $args nor $MyInvocation.UnboundArguments will do their best to hide that information from you. They'll appear to be completely empty.
You can print the args with >> echo "$(#args)", but that also provides the very weird side effect of telling the Debugger to continue. I think the splatting is adding an extra newline and that's ending up in the Command Window.
The best workaround I have for that is to add $theargs = $args at the top of your script and remember to use $theargs in the debugger.
I am writing a release script in powershell and need to invoke a custom executable and pass in a bunch of parameters to the executable. Few of these parameters are assigned values from various conditions and executions in the script. I see that the values are not getting evaluated when the executable is invoked. Some of the variables need to be passed in as a series of arguments inside double quotes as well. Shown below is a smaple call
mysample.exe '-forcerebuild' '-release=$CALC_VERSION' '-projfile=sample.proj' '-buildoptions="/p:AllowDevDependencies=true /p:AssemblyVersion=$CALC_ASSEMBLY_VERSION /flp:LogFile=$env:temp\build.log /p:BaseIntermediateOutputPath=$PROJECT_BASE\build\ /clp:nosummary"'
All the variables that need to be evaluated are highlighted. The exe expects all the options provided to -buildoptions inside quoted -buildoptions="all build options"
The values don't seem to get evaluated. However, if i put build options as a separate variable and print it, the values seem to get evaluated. I am new to powershell and would really appreciate any help with this.
Note that powershell doesn't do variable expansion inside single quoted strings. For example:
$test_variable = "test"
write-host "this is a $test_variable"
write-host 'this is a $test_variable'
will print
this is a test
this is a $test_variable
Also, powershell has problems in passing arguments to exes. There is a util called EchoArgs.exe that comes with Powershell Community Extensions. Use that and pass your argument to that to see if they are passed fine.
Let's look at the code below
$SBK="0x1682CCD8 0x8A1A43EA 0xA532EEB6 0xECFE1D98"
./windows/nvflash/nvflash.exe --sbk 0x1682CCD8 0x8A1A43EA 0xA532EEB6 0xECFE1D98
./windows/nvflash/nvflash.exe --sbk "0x1682CCD8 0x8A1A43EA 0xA532EEB6 0xECFE1D98"
./windows/nvflash/nvflash.exe --sbk $SBK
I have define a string var $SBK and then I'm going to pass it for some app. The first process call is working properly. The second one fails and therefore application doesn't accepts quotes. But the third call is failed too with the same error. It seems that powershell passes quotes, those are causing errors. But how to eliminate them? Thanks beforehand.
Try doing
iex "./windows/nvflash/nvflash.exe --sbk $SBK"
Also, get echoargs.exe from PowerShell Community Extensions to see how args are passed from Powershell to commands etc.
You should probably not use Invoke-Expression (see This Post from the PowerShell Team)
Instead, you can create an array of arguments, and then pass them using the call operator. See this post of mine on the subject for more details.
In your case, it would look something like this:
$SBKArgs="--sbk", "0x1682CCD8", "0x8A1A43EA", "0xA532EEB6", "0xECFE1D98"
$cmd = Get-Command ./windows/nvflash/nvflash.exe
& $cmd $sbkargs
Hope this Helps