Ive got a very basic powershell script which uses Start-Process to start another .sh script, this is working and the scripts do execute but what I need is to be able to capture the output of the called script.
Content of the scripts is below:
main.ps1
Start-Process 'C:\Program Files\Git\git-bash.exe' -ArgumentList '-- C:\test\sub.sh' -Wait -RedirectStandardOutput output.txt
sub.sh
#!/bin/bash
echo "Hello World"
The sub.sh launches and prints out Hello World in its own console, but I really need the output to either go to the calling powershell scripts console window, or to a file. The file I specify in the -RedirectStandardOutput parameter is created, but is empty.
How can I get the sh script to print to standard out to the calling script?
Thank you
git-bash is in a different world than powershell so you can not directly redirect output or use -RedirectStandardOutput.
As you supposed, you can use an temporary file but the trick is to use internal bash operand ">" to redirect output to the file from bash process :
#!/bin/bash
echo "Hello from bash World" > /c/test/tempFile.txt
Then call it from powershell, you might hide the window also :
Start-Process 'C:\Program Files\Git\git-bash.exe' -ArgumentList C:\test\sub.sh -Wait -WindowStyle Hidden
$s = Get-Content c:\test\tempFile.txt
Write-Host "s=$s"
Remove-Item c:\test\tempFile.txt
Note : You have to specifilly fully qualified path.
Another option might be using Windows 10 own bash interpreter : https://stackoverflow.com/a/44359679/11867971
As written in sub.sh, the program to execute sh files is /bin/bash, not git-bash.exe.
$output = & 'C:\Program Files\Git\usr\bin\bash.exe' C:\test\sub.sh
$output
Hello World
Related
What is the required syntax to redirect standard input/output on Windows PowerShell?
On Unix, we use:
$./program <input.txt >output.txt
How do I execute the same task in PowerShell?
You can't hook a file directly to stdin, but you can still access stdin.
Get-Content input.txt | ./program > output.txt
If there is someone looking for 'Get-Content' alternative for large files (as me) you can use CMD in PowerShell:
cmd.exe /c ".\program < .\input.txt"
Or you can use this PowerShell command:
Start-Process .\program.exe -RedirectStandardInput .\input.txt -NoNewWindow -Wait
It will run the program synchronously in same window. But I was not able to find out how to write result from this command to a variable when I run it in PowerShell script because it always writes data to the console.
EDIT:
To get output from Start-Process you can use option
-RedirectStandardOutput
for redirecting output to file and then read it from file:
Start-Process ".\program.exe" -RedirectStandardInput ".\input.txt" -RedirectStandardOutput ".\temp.txt" -NoNewWindow -Wait
$Result = Get-Content ".\temp.txt"
For output redirection you can use:
command > filename Redirect command output to a file (overwrite)
command >> filename APPEND into a file
command 2> filename Redirect Errors
Input redirection works in a different way. For example see this Cmdlet http://technet.microsoft.com/en-us/library/ee176843.aspx
Or you can do:
something like:
$proc = Start-Process "my.exe" "exe commandline arguments" -PassThru -wait -NoNewWindow -RedirectStandardError "path to error file" -redirectstandardinput "path to a file from where input comes"
if you want to know if process errored out, add following code:
$exitCode = $proc.get_ExitCode()
if ($exitCode){
$errItem = Get-Item "path to error file"
if ($errItem.length -gt 0){
$errors = Get-Content "path to error file" | Out-String
}
}
I find that this way I do have a better handle on execution of your scripts, when you need to handle external program/process. Otherwise I have encountered situations where script would hang out on some of external process errors.
You can also do this to have standard error and standard out go to the same place (note that in cmd, 2>&1 must be last):
get-childitem foo 2>&1 >log
Note that ">" is the same as "| out-file", and by default the encoding is unicode or utf 16. Also be careful with ">>", because it can mix ascii and unicode in the same text file. "| add-content" probably works better than ">>". "| set-content" might be preferable to ">".
There's 6 streams now. More info: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_redirection?view=powershell-5.1
I think all you can do is save to a text file and then read it into a variable after.
I am trying to run an executable through powershell to run headless, to install a program onto a VM/LocalHost machine. I can get the wizard to open, but for whatever reason I cannot get it to run headless. Here is the cmd line that I run that works:
start /WAIT setup.exe /clone_wait /S /v" /qn"
This is my attempts in powershell
Start-Process .\setup.exe /S -Wait -PassThru
Start-Process .\setup.exe /S /v /qn -Wait -PassThru
Start-Process setup.exe -ArgumentList '/clone_wait /S /v /qn' -Wait
In the cmd line instance the application installs without issue - in the powershell instance the wizard opens and is on the first "Next" prompt. Any help would be appreciated!
I also attempted to add the additional parameters "/v" and "/qn" which return an error : Start-Process : A positional parameter cannot be found that accepts argument '/v'
The bottom attempt runs but it's not waiting for the installation to complete
You may be overthinking it. Remember that PowerShell is a shell. One of the purposes of a shell is to run commands that you type.
Thus: You don't need Start-Process. Just type the command to run and press Enter.
PS C:\> .\setup.exe /clone_wait /S /v /qn
Now if the executable (or script) you want to run contains spaces in the path or name, then use the call/invocation operator (&) and specify the quotes; for example:
PS C:\> & "\package files\setup.exe" /clone_wait /S /v /qn
(This behavior is the same no matter whether you are at the PowerShell prompt or if you put the command in a script.)
This worked for me. You need to quote the whole argumentlist, plus embed double quotes to pass what you want to /v.
start-process -wait SetupStata16.exe -ArgumentList '/s /v"/qb ADDLOCAL=core,StataMP64"'
Running the command normally and then using wait-process after might be a simpler alternative, if you're sure there's only one process with that name:
notepad
wait-process notepad
To follow-up to all that you have been given thus far. Running executables via PowerShell is a well-documented use case.
PowerShell: Running Executables
Solve Problems with External Command Lines in PowerShell
Top 5 tips for running external commands in Powershell
Using Windows PowerShell to run old command-line tools (and their
weirdest parameters)
So, from the first link provides more validation of what you've been given.
5. The Call Operator &
Why: Used to treat a string as a SINGLE command. Useful for dealing with spaces.
In PowerShell V2.0, if you are running 7z.exe (7-Zip.exe) or another command that starts with a number, you have to use the command invocation operator &.
The PowerShell V3.0 parser do it now smarter, in this case you don’t need the & anymore.
Details: Runs a command, script, or script block. The call operator, also known as the "invocation operator," lets you run commands that are stored in variables and represented by strings. Because the call operator does not parse the command, it cannot interpret command parameters
Example:
& 'C:\Program Files\Windows Media Player\wmplayer.exe' "c:\videos\my home video.avi" /fullscreen
Things can get tricky when an external command has a lot of parameters or there are spaces in the arguments or paths!
With spaces you have to nest Quotation marks and the result it is not always clear!
In this case it is better to separate everything like so:
$CMD = 'SuperApp.exe'
$arg1 = 'filename1'
$arg2 = '-someswitch'
$arg3 = 'C:\documents and settings\user\desktop\some other file.txt'
$arg4 = '-yetanotherswitch'
& $CMD $arg1 $arg2 $arg3 $arg4
# or same like that:
$AllArgs = #('filename1', '-someswitch', 'C:\documents and settings\user\desktop\some other file.txt', '-yetanotherswitch')
& 'SuperApp.exe' $AllArgs
6. cmd /c - Using the old cmd shell
** This method should no longer be used with V3
Why: Bypasses PowerShell and runs the command from a cmd shell. Often times used with a DIR which runs faster in the cmd shell than in PowerShell (NOTE: This was an issue with PowerShell v2 and its use of .Net 2.0, this is not an issue with V3).
Details: Opens a CMD prompt from within powershell and then executes the command and returns the text of that command. The /c tells CMD that it should terminate after the command has completed. There is little to no reason to use this with V3.
Example:
#runs DIR from a cmd shell, DIR in PowerShell is an alias to GCI. This will return the directory listing as a string but returns much faster than a GCI
cmd /c dir c:\windows
7. Start-Process (start/saps)
Why: Starts a process and returns the .Net process object Jump if -PassThru is provided. It also allows you to control the environment in which the process is started (user profile, output redirection etc). You can also use the Verb parameter (right click on a file, that list of actions) so that you can, for example, play a wav file.
Details: Executes a program returning the process object of the application. Allows you to control the action on a file (verb mentioned above) and control the environment in which the app is run. You also have the ability to wait on the process to end. You can also subscribe to the processes Exited event.
Example:
#starts a process, waits for it to finish and then checks the exit code.
$p = Start-Process ping -ArgumentList "invalidhost" -wait -NoNewWindow -PassThru
$p.HasExited
$p.ExitCode
#to find available Verbs use the following code.
$startExe = new-object System.Diagnostics.ProcessStartInfo -args PowerShell.exe
$startExe.verbs
This is my code:
set-location [PATH]
$A = Start-Process -FilePath .\refresh.bat -Wait
set-location C:\
When executed in powershell, the system opens a Command prompt window and executes the bat file without issue. The problem is that the window closes and I cannot see if there was an error if it succeeds.
I want to keep the CMD window open.
I also tried at the end of the bat file:
:END
cmd /k
but no luck.
First, unless you specifically need to run the batch file in a new window, do not use Start-Process - use direct invocation instead, which is implicitly synchronous and allows you to capture or redirect output:
# Invoke the batch file synchronously (wait for it to exit)
# and capture its (standard) output in variable $A
# To print the batch file's output to the console instead, just use:
# .\refresh.bat
$A = .\refresh.bat
See this answer for more information.
Also note Start-Process never allows you to capture the invoked program's output directly (you can only redirect it to files with -RedirectStandardOutput and -RedirectStandardOutput); your specific command captures nothing[1] in $A; adding -PassThru does return something, but not the program's output, but a process-information object (System.Diagnostics.Process).
If you do need to run the batch file in a new window and want to keep that window open:
Start-Process -Wait -FilePath cmd -ArgumentList '/k .\refresh.bat'
Relying on positional parameter binding, the above can be simplified to:
Start-Process -Wait cmd '/k .\refresh.bat'
[1] Strictly speaking, $A is assigned the [System.Management.Automation.Internal.AutomationNull]::Value singleton, which in most contexts behaves like $null.
Thank you mklement0 with your post gave me the solution I wanted. This is how I solved it.
set-location [PATH]
$A = Start-Process -FilePath .\refresh.bat -Wait -NoNewWindow
set-location C:\
-NoNewWindow allowed me to run my batch in the same powershell window getting the feedback of the bat file. That way I have errors if any and success status if no errors.
Thanks!
We are migrating perl script to powershell script.
In Perl the code is as shown below
$rc='D:\\EmailConnector\\run.bat> $EmailConnector_log;';
I tried as shown below but not working
StartProcess "cmd.exe" "/c D:\EmailConnector\run.bat> $EmailConnector_log"
When I tried as shown below the .bat script ran, but I want to update the log file. Could you help me on this.
StartProcess run.bat -workingdirectory "D:\EmailConnector"
The .bat file consist of jar file for email functionality. But we want to get log in log file.
Use the call operator (&), like this:
& 'D:\EmailConnector\run.bat' > $EmailConnector_log
The return value of the batch script is automatically put into the variable $LastExitCode.
Is that what you mean?
Start-Process "cmd" -ArgumentList '/c','D:\EmailConnector\run.bat' -WorkingDirectory "D:\EmailConnector"
or this one if you need another argument for logfile
Start-Process "cmd" -ArgumentList '/c','D:\EmailConnector\run.bat','EmailConnector_log' -WorkingDirectory "D:\EmailConnector"
Or, since there are no spaces in the path, you can just execute the batch file directly from PowerShell:
D:\EmailConnector\run.bat > $EmailConnector_log
This is one of the advantages of PowerShell being both a "shell" and a "scripting language". Execution of batch, cmd, vbs, exe files is straightforward - usually. Parameter passing can be an issue but these days that is easily solved with the stop parsing operator: --%.
I'm writing a Powershell script that takes in a text file as a parameter. The text file looks similar to this:
echo "1"
echo "2"
echo "3"
What I would want is for each line to be executed in a new Powershell instance. So in the example above, 3 additional instances would be created and each of the 3 would execute one line from the text file. I'm able to launch instances, but I cannot get the instances to treat the lines in the file as commands.
$textFile=$args[0] #File with Powershell commands
foreach($cmdd in get-content $textFile){
cmd /c start powershell -NoExit -command {param($cmdd) iex $cmdd} -ArgumentList $cmdd
}
Running this code opens the instances, prints a lot of information, and then immediately closes. It closes so quickly that I cannot see what the info is. However, since the text file is only composed of printing the numbers 1, 2, and 3, I don't think that it's working correctly. Is there also a way to keep the windows from closing after execution?
If you're launching additional instances of PowerShell from PowerShell, you won't need to call cmd. Try using Start-Process:
$textFile=$args[0] #File with Powershell commands
foreach($cmdd in get-content $textFile){
Start-Process -FilePath powershell -ArgumentList "-NoExit -Command $cmdd"
}
This will leave newly created instances open as you have asked.
Switch from CMD /C to CMD /K to leave the command session open after the command finishes.