PowerShell how to grep command output

Question

In PowerShell I have tried   alias   select-string Alias   This fails even though Alias is clearly in the output  I know this is because select-string is operating on some object and not the actual output string    What can be done about it

User · Answer

If you truly want to  grep  the formatted output  display strings  then go with Mike s approach   There are definitely times where this comes in handy   However if you want to try embracing PowerShell s object pipeline nature  then try this   First  check out the properties on the objects flowing down the pipeline   PS gt  alias   Get-Member      TypeName  System Management Automation AliasInfo  Name                MemberType     Definition ----                ----------     ---------- Equals              Method         bool Equals System Object obj  GetHashCode         Method         int GetHashCode   GetType             Method         type GetType   ToString            Method         string ToString    lt snip gt   Definition         Property       System String Definition  get    lt snip gt    Note the Definition property which is a header you see when you display the output of Get-Alias  alias  e g    PS gt  alias  CommandType     Name            Definition  -----------     ----           ---------- Alias                          ForEach-Object  lt snip gt    Usually the header title matches the property name but not always   That is where using Get-Member comes in handy   It shows you what you need to  script  against   Now if what you want to  grep  is the Definition property contents then consider this   Rather than just grepping that one property s value  you can instead filter each AliasInfo object in the pipepline by the contents of this property and you can use a regex to do it e g    PS gt  alias   Where-Object     Definition -match  alias    CommandType     Name                   Definition -----------     ----                   ---------- Alias           epal                   Export-Alias Alias           gal                    Get-Alias Alias           ipal                   Import-Alias Alias           nal                    New-Alias Alias           sal                    Set-Alias   In this example I use the Where-Object cmdlet to filter objects based on some arbitrary script   In this case  I filter by the Defintion property matched against the regex  alias    Only those objects that return true for that filter are allowed to propagate down the pipeline and get formatted for display on the host     BTW if you re typing this  then you can use one of two aliases for Where-Object -  Where  or       For example   PS gt  gal        Definition -match  -Item

User · Answer

For a more flexible and lazy solution  you could match all properties of the objects   Most of the time  this should get you the behavior you want  and you can always be more specific when it doesn t   Here s a grep function that works based on this principle   Function Select-ObjectPropertyValues       param       Parameter Mandatory  true Position 0        String       Pattern       Parameter ValueFromPipeline        input        input   Where-Object      PSObject Properties   Where-Object     Value -match  Pattern    Measure-Object  count -gt 0    Write-Output

User · Answer

The proposed solution is just to much work for something that can be done like this   Get-Alias -Definition Write

User · Answer

There are two problems  As in the question  select-string needs to operate on the output string  which can be had from  out-string   Also  select-string doesn t operate linewise on strings that are piped to it  Here is a generic solution   alias out-string  -split   n    select-string Write

User · Answer

PS gt  alias   Where-Object     Definition -match  alias    CommandType     Name                   Definition -----------     ----                   ---------- Alias           epal                   Export-Alias Alias           gal                    Get-Alias Alias           ipal                   Import-Alias Alias           nal                    New-Alias Alias           sal                    Set-Alias  what would be contradict of match in PS then as in to get field not matching a certain value in a column

User · Answer

Your problem is that alias emits a stream of AliasInfo objects  rather than a stream of strings  This does what I think you want   alias   out-string -stream   select-string Alias   or as a function  function grep      input   out-string -stream   select-string  args    alias   grep Alias   When you don t handle things that are in the pipeline  like when you just ran  alias    the shell knows to use the ToString   method on each object  or use the output formats specified in the ETS info

User · Answer

I think this solution is easier and better  use directly the function findstr   alias   findstr -i Write   You can also make an alias to use grep word   new-alias grep findstr

User · Answer

Try this  PS C   gt  ipconfig  displaydns   Select-String -Pattern  www yahoo com  -Context 0 7   gt      www yahoo com       ----------------------------------------  gt      Record Name             www yahoo com       Record Type             5       Time To Live            27       Data Length             8       Section                 Answer       CNAME Record            new-fp-shed wg1 b yahoo com

[powershell] PowerShell: how to grep command output?

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