593

In a cmd prompt, you can run two commands on one line like so:

ipconfig /release & ipconfig /renew

When I run this command in PowerShell, I get:

Ampersand not allowed. The `&` operator is reserved for future use

Does PowerShell have an operator that allows me to quickly produce the equivalent of & in a cmd prompt?

Any method of running two commands in one line will do. I know that I can make a script, but I'm looking for something a little more off the cuff.

Peter Mortensen
  • 12,326
David
  • 9,854

5 Answers5

826

Use a semicolon to chain commands in PowerShell:

ipconfig /release; ipconfig /renew
Peter Mortensen
  • 12,326
Squeezy
  • 9,850
  • 1
  • 18
  • 18
73

In PowerShell 7, we have Pipeline chain operators which allows you to add some conditional element to your sequential one-line commands

The operators are:

  • && this will run the second command only if the first one succeeds.
  • || this will run the second command only if the first one fails.

examples:

C:\> Write-Host "This will succeed" && Write-Host "So this will run too"
This will succeed
So this will run too

C:> Write-Error "This is an error" && Write-Host "So this shouldn't run"
Write-Error "This is an error" && Write-Host "So this shouldn't run": This is an error


C:> Write-Host "This will succeed" || Write-Host "This won't run"
This will succeed


C:> Write-Error "This is an error" || Write-Host "That's why this runs"
Write-Error "This is an error" || Write-Host "That's why this runs" 
This is an error
That's why this runs

of course you can chain them even more together like x && y || z etc.

this also works for old cmd-like commands like ipconfig

> ipconfig && Write-Error "abc" || ipconfig

Windows-IP-Konfiguration


Ethernet-Adapter Ethernet:


Verbindungsspezifisches DNS-Suffix: xxx
   Verbindungslokale IPv6-Adresse  . : xxx
   IPv4-Adresse  . . . . . . . . . . : xxx
   Subnetzmaske  . . . . . . . . . . : 255.255.255.0
   Standardgateway . . . . . . . . . : xxx
ipconfig && Write-Error "abc" || ipconfig: abc


Windows-IP-Konfiguration


Ethernet-Adapter Ethernet:


Verbindungsspezifisches DNS-Suffix: xxx
   Verbindungslokale IPv6-Adresse  . : xxx
   IPv4-Adresse  . . . . . . . . . . : xxx
   Subnetzmaske  . . . . . . . . . . : 255.255.255.0
   Standardgateway . . . . . . . . . : xxx

These operators use the $? and $LASTEXITCODE variables to determine if a pipeline failed. This allows you to use them with native commands and not just with cmdlets or functions.

Source: https://docs.microsoft.com/en-us/powershell/scripting/whats-new/what-s-new-in-powershell-70?view=powershell-7

SimonS
  • 9,869
37

A semicolon will link the commands as the previous answer stated, although there is a key difference to the behaviour with the & operator in the MS-DOS style command interpreter.

In the command interpreter, the variable substitution takes place when the line is read. This allows some neat possibilities such as swapping variables without an interim:

set a=1
set b=2
set a=%b% & set b=%a%
echo %a%
echo %b%

Would result in:

2
1

As far as I know, there is no way to replicate this behaviour in PowerShell. Some may argue that's a good thing.

There is in fact a way to do this in PowerShell:

$b, $a = $a, $b

It will result in a single line swapping of the variable values.

Marcello Miorelli
  • 324
  • 7
  • 22
Dave_J
  • 481
15

For PowerShell 5 (default install for Windows machines for the foreseeable future), you can of course use a semicolon to separate statements, but all statements will be executed by default even if one fails. Personally, I prefer to run things so that if one thing fails the whole line stops in the REPL and I imagine a lot of other folks do as well.

$ErrorActionPreference lets you control the behavior of what happens when a statement fails but is a non-terminating error (which are most errors including command not found errors). You can set this variable $ErrorActionPreference="Stop" in order to emulate the behavior of && in Bash and PowerShell 7 for the scope of this variable.

$ErrorActionPreference="Stop"
# Line break
fakeCommand; echo "Here"

I have had trouble finding precise documentation for this behavior, but this variable seems to be dynamically scoped so you can override it in a block temporarily if you don't want to set it globally.

Invoke-Command -ScriptBlock {$ErrorActionPreference="Stop"; fakeCommand; echo "Here"}

Finally, if you want something reusable, you can use this higher order function.

function Run-Block-With-Error($block) {
    $ErrorActionPreference="Stop"
    Invoke-Command -ScriptBlock $block
}

Which is then used as follows.

Run-Block-With-Error {fakeCommand; echo "Here"}

Note in the examples above that "Here" is not printed since fakeCommand fails as it is not a real command.

I have tested the code provided in this solution for both PowerShell 5 and 7 and it should be fully portable, at least on Windows. While PowerShell 7 should be very similar on different platforms, I did not test these commands on Linux or MacOS.

Dyllon Gagnier
  • 251
-1
"C:\\msys64\\mingw64\\bin\\g++.exe -g3 -Wall \"${file}\" -o \"${fileDirname}\\${fileBasenameNoExtension}.exe\" ; &\"${fileDirname}\\${fileBasenameNoExtension}.exe\""

In a powershell

Toto
  • 19,304
Abhishek Sa
  • 1