Powershell – How to enter a multi-line command

multilinepowershell

Is it possible to split a PowerShell command line over multiple lines?

In Visual Basic I can use the underscore (_) to continue the command in the next line.

Best Solution

You can use a space followed by the grave accent (backtick):

Get-ChildItem -Recurse `
  -Filter *.jpg `
  | Select LastWriteTime

However, this is only ever necessary in such cases as shown above. Usually you get automatic line continuation when a command cannot syntactically be complete at that point. This includes starting a new pipeline element:

Get-ChildItem |
  Select Name,Length

will work without problems since after the | the command cannot be complete since it's missing another pipeline element. Also opening curly braces or any other kind of parentheses will allow line continuation directly:

$x=1..5
$x[
  0,3
] | % {
  "Number: $_"
}

Similar to the | a comma will also work in some contexts:

1,
2

Keep in mind, though, similar to JavaScript's Automatic Semicolon Insertion, there are some things that are similarly broken because the line break occurs at a point where it is preceded by a valid statement:

return
  5

will not work.

Finally, strings (in all varieties) may also extend beyond a single line:

'Foo
bar'

They include the line breaks within the string, then.

Related Solutions

Powershell – How to handle command-line arguments in PowerShell

You are reinventing the wheel. Normal PowerShell scripts have parameters starting with -, like script.ps1 -server http://devserver

Then you handle them in param section in the beginning of the file.

You can also assign default values to your params, read them from console if not available or stop script execution:

 param (
    [string]$server = "http://defaultserver",
    [Parameter(Mandatory=$true)][string]$username,
    [string]$password = $( Read-Host "Input password, please" )
 )

Inside the script you can simply

write-output $server

since all parameters become variables available in script scope.

In this example, the $server gets a default value if the script is called without it, script stops if you omit the -username parameter and asks for terminal input if -password is omitted.

Update: You might also want to pass a "flag" (a boolean true/false parameter) to a PowerShell script. For instance, your script may accept a "force" where the script runs in a more careful mode when force is not used.

The keyword for that is [switch] parameter type:

 param (
    [string]$server = "http://defaultserver",
    [string]$password = $( Read-Host "Input password, please" ),
    [switch]$force = $false
 )

Inside the script then you would work with it like this:

if ($force) {
  //deletes a file or does something "bad"
}

Now, when calling the script you'd set the switch/flag parameter like this:

.\yourscript.ps1 -server "http://otherserver" -force

If you explicitly want to state that the flag is not set, there is a special syntax for that

.\yourscript.ps1 -server "http://otherserver" -force:$false

Links to relevant Microsoft documentation (for PowerShell 5.0; tho versions 3.0 and 4.0 are also available at the links):

Json – Are multi-line strings allowed in JSON

JSON does not allow real line-breaks. You need to replace all the line breaks with \n.

eg:

"first line second line"

can saved with:

"first line\nsecond line"

Note:

for Python, this should be written as:

"first line\\nsecond line"

where \\ is for escaping the backslash, otherwise python will treat \n as the control character "new line"

Best Solution

Related Solutions

Powershell – How to handle command-line arguments in PowerShell

Json – Are multi-line strings allowed in JSON

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