Powershell equivalent of bash ampersand for forking running background processes

Question

In bash the ampersand   amp   can be used to run a command in the background and return interactive control to the user before the command has finished running  Is there an equivalent method of doing this in Powershell   Example of usage in bash    sleep 30  amp

User · Answer

You can use PowerShell job cmdlets to achieve your goals.

There are 6 job related cmdlets available in PowerShell.

Get-Job
- Gets Windows PowerShell background jobs that are running in the current session
Receive-Job
- Gets the results of the Windows PowerShell background jobs in the current session
Remove-Job
- Deletes a Windows PowerShell background job
Start-Job
- Starts a Windows PowerShell background job
Stop-Job
- Stops a Windows PowerShell background job
Wait-Job
- Suppresses the command prompt until one or all of the Windows PowerShell background jobs running in the session are complete

If interesting about it, you can download the sample How to create background job in PowerShell

User · Answer

tl dr  Start-Process powershell   sleep 30

User · Answer

Seems that the script block passed to Start-Job is not executed with the same current directory as the Start-Job command  so make sure to specify fully qualified path if needed    For example   Start-Job   C  absolute path to command exe --afileparameter C  absolute path to file txt

User · Answer

I ve used the solution described here http   jtruher spaces live com blog cns 7143DA6E51A2628D 130 entry successfully in PowerShell v1 0   It definitely will be easier in PowerShell v2 0

User · Answer

As long as the command is an executable or a file that has an associated executable  use Start-Process  available from v2    Start-Process -NoNewWindow ping google com   You can also add this as a function in your profile   function bg    Start-Process -NoNewWindow  args    and then the invocation becomes   bg ping google com   In my opinion  Start-Job is an overkill for the simple use case of running a process in the background    Start-Job does not have access to your existing scope  because it runs in a separate session   You cannot do  Start-Job  notepad  myfile   Start-Job does not preserve the current directory  because it runs in a separate session   You cannot do  Start-Job  notepad myfile txt   where myfile txt is in the current directory  The output is not displayed automatically  You need to run Receive-Job with the ID of the job as parameter    NOTE  Regarding your initial example   bg sleep 30  would not work because sleep is a Powershell commandlet  Start-Process only works when you actually fork a process

User · Answer

ps2 gt  start-job  start-sleep 20    i have not yet figured out how to get stdout in realtime  start-job requires you to poll stdout with get-job  update  i couldn t start-job to easily do what i want which is basically the bash  amp  operator  here s my best hack so far  PS gt  notepad  profile  edit init script -- added these lines function beep   write-host  a   function ajp   start powershell  ant java-platform out-null beep     new window  stderr only  beep when done function acjp   start powershell  ant clean java-platform out-null beep    PS gt     profile  re-load profile script PS gt  ajp

User · Answer

You can use PowerShell job cmdlets to achieve your goals.

There are 6 job related cmdlets available in PowerShell.

Get-Job
- Gets Windows PowerShell background jobs that are running in the current session
Receive-Job
- Gets the results of the Windows PowerShell background jobs in the current session
Remove-Job
- Deletes a Windows PowerShell background job
Start-Job
- Starts a Windows PowerShell background job
Stop-Job
- Stops a Windows PowerShell background job
Wait-Job
- Suppresses the command prompt until one or all of the Windows PowerShell background jobs running in the session are complete

If interesting about it, you can download the sample How to create background job in PowerShell

User · Answer

As long as the command is an executable or a file that has an associated executable  use Start-Process  available from v2    Start-Process -NoNewWindow ping google com   You can also add this as a function in your profile   function bg    Start-Process -NoNewWindow  args    and then the invocation becomes   bg ping google com   In my opinion  Start-Job is an overkill for the simple use case of running a process in the background    Start-Job does not have access to your existing scope  because it runs in a separate session   You cannot do  Start-Job  notepad  myfile   Start-Job does not preserve the current directory  because it runs in a separate session   You cannot do  Start-Job  notepad myfile txt   where myfile txt is in the current directory  The output is not displayed automatically  You need to run Receive-Job with the ID of the job as parameter    NOTE  Regarding your initial example   bg sleep 30  would not work because sleep is a Powershell commandlet  Start-Process only works when you actually fork a process

User · Answer

tl dr  Start-Process powershell   sleep 30

User · Answer

I ve used the solution described here http   jtruher spaces live com blog cns 7143DA6E51A2628D 130 entry successfully in PowerShell v1 0   It definitely will be easier in PowerShell v2 0

User · Answer

I ve used the solution described here http   jtruher spaces live com blog cns 7143DA6E51A2628D 130 entry successfully in PowerShell v1 0   It definitely will be easier in PowerShell v2 0

User · Answer

From PowerShell Core 6 0 you are able to write  amp  at end of command and it will be equivalent to running you pipeline in background in current working directory   It s not equivalent to  amp  in bash  it s just a nicer syntax for current PowerShell jobs feature  It returns a job object so you can use all other command that you would use for jobs  For example Receive-Job   C  utils gt  ping google com  amp   Id     Name            PSJobTypeName   State         HasMoreData     Location             Command --     ----            -------------   -----         -----------     --------             ------- 35     Job35           BackgroundJob   Running       True            localhost            Microsoft PowerShell M      C  utils gt  Receive-Job 35  Pinging google com  172 217 16 14  with 32 bytes of data  Reply from 172 217 16 14  bytes 32 time 11ms TTL 55 Reply from 172 217 16 14  bytes 32 time 11ms TTL 55 Reply from 172 217 16 14  bytes 32 time 10ms TTL 55 Reply from 172 217 16 14  bytes 32 time 10ms TTL 55  Ping statistics for 172 217 16 14      Packets  Sent   4  Received   4  Lost   0  0  loss   Approximate round trip times in milli-seconds      Minimum   10ms  Maximum   11ms  Average   10ms C  utils gt    If you want to execute couple of statements in background you can combine  amp  call operator      script block and this new  amp  background operator like here    amp    cd   SomeDir     SomeLongRunningOperation bat  cd        amp      Here s some more info from documentation pages   from What s New in PowerShell Core 6 0      Support backgrounding of pipelines with ampersand   amp     3360       Putting  amp  at the end of a pipeline causes the pipeline to be run as a PowerShell job  When a pipeline is backgrounded  a job object is returned  Once the pipeline is running as a job  all of the standard  -Job cmdlets can be used to manage the job  Variables  ignoring process-specific variables  used in the pipeline are automatically copied to the job so Copy-Item  foo  bar  amp  just works  The job is also run in the current directory instead of the user s home directory  For more information about PowerShell jobs  see about Jobs    from about operators   Ampersand background operator  amp       Ampersand background operator  amp       Runs the pipeline before it in a PowerShell job  The ampersand background operator acts similarly to the UNIX  ampersand operator  which famously runs the command before it as a background process  The ampersand background operator is built on top of PowerShell jobs so it shares a lot of functionality with Start-Job  The following command contains basic usage of the ampersand background operator   Get-Process -Name pwsh  amp        This is functionally equivalent to the following usage of Start-Job       Start-Job -ScriptBlock  Get-Process -Name pwsh       Since it s functionally equivalent to using Start-Job  the ampersand background operator returns a Job object just like Start-Job does  This means that you are able to use Receive-Job and Remove-Job just as you would if you had used Start-Job to start the job    job   Get-Process -Name pwsh  amp  Receive-Job  job       Output  NPM K     PM M       WS M      CPU s       Id  SI ProcessName ------    -----      -----     ------      --  -- -----------     0     0 00     221 16      25 90    6988 988 pwsh     0     0 00     140 12      29 87   14845 845 pwsh     0     0 00      85 51       0 91   19639 988 pwsh    job   Get-Process -Name pwsh  amp  Remove-Job  job       For more information on PowerShell jobs  see about Jobs

User · Answer

From PowerShell Core 6 0 you are able to write  amp  at end of command and it will be equivalent to running you pipeline in background in current working directory   It s not equivalent to  amp  in bash  it s just a nicer syntax for current PowerShell jobs feature  It returns a job object so you can use all other command that you would use for jobs  For example Receive-Job   C  utils gt  ping google com  amp   Id     Name            PSJobTypeName   State         HasMoreData     Location             Command --     ----            -------------   -----         -----------     --------             ------- 35     Job35           BackgroundJob   Running       True            localhost            Microsoft PowerShell M      C  utils gt  Receive-Job 35  Pinging google com  172 217 16 14  with 32 bytes of data  Reply from 172 217 16 14  bytes 32 time 11ms TTL 55 Reply from 172 217 16 14  bytes 32 time 11ms TTL 55 Reply from 172 217 16 14  bytes 32 time 10ms TTL 55 Reply from 172 217 16 14  bytes 32 time 10ms TTL 55  Ping statistics for 172 217 16 14      Packets  Sent   4  Received   4  Lost   0  0  loss   Approximate round trip times in milli-seconds      Minimum   10ms  Maximum   11ms  Average   10ms C  utils gt    If you want to execute couple of statements in background you can combine  amp  call operator      script block and this new  amp  background operator like here    amp    cd   SomeDir     SomeLongRunningOperation bat  cd        amp      Here s some more info from documentation pages   from What s New in PowerShell Core 6 0      Support backgrounding of pipelines with ampersand   amp     3360       Putting  amp  at the end of a pipeline causes the pipeline to be run as a PowerShell job  When a pipeline is backgrounded  a job object is returned  Once the pipeline is running as a job  all of the standard  -Job cmdlets can be used to manage the job  Variables  ignoring process-specific variables  used in the pipeline are automatically copied to the job so Copy-Item  foo  bar  amp  just works  The job is also run in the current directory instead of the user s home directory  For more information about PowerShell jobs  see about Jobs    from about operators   Ampersand background operator  amp       Ampersand background operator  amp       Runs the pipeline before it in a PowerShell job  The ampersand background operator acts similarly to the UNIX  ampersand operator  which famously runs the command before it as a background process  The ampersand background operator is built on top of PowerShell jobs so it shares a lot of functionality with Start-Job  The following command contains basic usage of the ampersand background operator   Get-Process -Name pwsh  amp        This is functionally equivalent to the following usage of Start-Job       Start-Job -ScriptBlock  Get-Process -Name pwsh       Since it s functionally equivalent to using Start-Job  the ampersand background operator returns a Job object just like Start-Job does  This means that you are able to use Receive-Job and Remove-Job just as you would if you had used Start-Job to start the job    job   Get-Process -Name pwsh  amp  Receive-Job  job       Output  NPM K     PM M       WS M      CPU s       Id  SI ProcessName ------    -----      -----     ------      --  -- -----------     0     0 00     221 16      25 90    6988 988 pwsh     0     0 00     140 12      29 87   14845 845 pwsh     0     0 00      85 51       0 91   19639 988 pwsh    job   Get-Process -Name pwsh  amp  Remove-Job  job       For more information on PowerShell jobs  see about Jobs

User · Answer

Seems that the script block passed to Start-Job is not executed with the same current directory as the Start-Job command  so make sure to specify fully qualified path if needed    For example   Start-Job   C  absolute path to command exe --afileparameter C  absolute path to file txt

User · Answer

ps2 gt  start-job  start-sleep 20    i have not yet figured out how to get stdout in realtime  start-job requires you to poll stdout with get-job  update  i couldn t start-job to easily do what i want which is basically the bash  amp  operator  here s my best hack so far  PS gt  notepad  profile  edit init script -- added these lines function beep   write-host  a   function ajp   start powershell  ant java-platform out-null beep     new window  stderr only  beep when done function acjp   start powershell  ant clean java-platform out-null beep    PS gt     profile  re-load profile script PS gt  ajp

User · Answer

I ve used the solution described here http   jtruher spaces live com blog cns 7143DA6E51A2628D 130 entry successfully in PowerShell v1 0   It definitely will be easier in PowerShell v2 0

User · Answer

You can do something like this      a   start-process -NoNewWindow powershell  timeout 10   done   -PassThru   And if you want to wait for it    a   wait-process   Bonus osx or linux version    a   start-process pwsh  -c   start-sleep 5   done   -PassThru    Example pinger script I have   The args are passed as an array    1   start -n powershell pinger comp001 -pa

User · Answer

You can do something like this      a   start-process -NoNewWindow powershell  timeout 10   done   -PassThru   And if you want to wait for it    a   wait-process   Bonus osx or linux version    a   start-process pwsh  -c   start-sleep 5   done   -PassThru    Example pinger script I have   The args are passed as an array    1   start -n powershell pinger comp001 -pa

[powershell] Powershell equivalent of bash ampersand (&) for forking/running background processes

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