MatchInfo<\/span> objects into Select-String.<\/span><\/h2>\n <\/p>\n
Here is where it gets fun! While the above statement is true, at this point the only command that produces these is Select-String. Let’s do a manual text substitution and restate the heading:<\/p>\n
You can pipe the output of Select-String into Select-String<\/p>\n
Yes \u2013 that\u2019s exactly correct and the implications are awesome. First it means that you can avoid some really hairy\/scary regular expressions for certain things. The regularity of the data we are working with doesn\u2019t allow a very interesting example but here is one:<\/p>\n
PS> ss<\/span> get *|ss<\/span> item<\/p>\nd-alias.txt:6:Alias<\/span> dir Get-ChildItem<\/span>
g-alias.txt:6:Alias gci<\/span> Get-ChildItem<\/span>
g-alias.txt:10:Alias gi<\/span> Get-Item
g-alias.txt:13:Alias gp<\/span> Get-ItemProperty<\/span>
l-alias.txt:5:Alias ls<\/span> Get-ChildItem<\/span><\/p>\n <\/p>\n
What is so cool about this is that the second Select-String is ONLY searching the results of the first Select-String (i.e. it is not reprocessing the file itself). This is great because it allows you to store the results of one long and expensive Select-String and then do a set of very quick and cheap searches against those results. In the example below I search all the txt files underneath the Windows Directory and store the results in a global variable. I then use that global variable to search for the same term a second time and show that it is 31 times faster to do it the second time. Of course the point would be that you\u2019d be looking for other things. This makes it easy to iterate through a series of investigations. We want you to explore you system so making it cheap to do so is important to us. <\/p>\n
PS> (Measure-Command {
>> $global:x<\/span> = dir c:\\windows *.txt –recurse<\/span> -ea SilentlyContinue<\/span> |
>> ss<\/span> PowerShell
>> }
>> ).TotalMilliseconds<\/span>
>>
Select-String : The file can not<\/span> be read: C:\\windows\\Tasks\\SCHEDLGU.TXT
At line:3 char:3
+ ss<\/span> <<<< PowerShell
5111.9712
PS> (Measure-Command {
>> $global:x<\/span> |
>> ss<\/span> PowerShell
>> }
>> ).TotalMilliseconds<\/span>
>>
166.9715
PS> [int<\/span>](5111\/166)
31
<\/span> <\/p>\nSelect-String outputs MatchInfo<\/span> objects not Strings<\/span><\/h2>\n <\/p>\n
As with most Cmdlets<\/span>, the output of Select-String looks like texts but is actually a stream of objects with a text rendering. This is great because then you can party with the object.<\/p>\nPS> ss<\/span> stop *<\/p>\nk-alias.txt:4:Alias kill Stop-Process
s-alias.txt:13:Alias spps<\/span> Stop-Process
s-alias.txt:14:Alias spsv<\/span> Stop-Service<\/p>\nPS> ss<\/span> Stop * |get-Member –MemberType<\/span> Property<\/p>\n TypeName<\/span>: Microsoft.PowerShell.Commands.MatchInfo<\/span><\/p>\nName MemberType<\/span> Definition
—- ———- ———-
Filename Property System.String<\/span> Filename {get;}
IgnoreCase<\/span> Property System.Boolean<\/span> IgnoreCase<\/span> {get;set<\/span>;}
Line Property System.String<\/span> Line {get;set<\/span>;}
LineNumber<\/span> Property System.Int32 LineNumber<\/span> {get;set<\/span>;}
Path Property System.String<\/span> Path {get;set<\/span>;}
Pattern Property System.String<\/span> Pattern {get;set<\/span>;}<\/p>\nPS> ss<\/span> “stop”,”new<\/span>.*ve<\/span>” *|fl *<\/p>\nIgnoreCase<\/span> : True
LineNumber<\/span> : 4
Line : Alias kill Stop-Process
Filename : k-alias.txt
Path : C:\\SSTest\\k-alias.txt
Pattern : stop<\/p>\nIgnoreCase<\/span> : True
LineNumber<\/span> : 6
Line : Alias mount New-PSDrive<\/span>
Filename : m-alias.txt
Path : C:\\SSTest\\m-alias.txt
Pattern : new.*ve<\/p>\nIgnoreCase<\/span> : True
LineNumber<\/span> : 5
Line : Alias ndr<\/span> New-PSDrive<\/span>
Filename : n-alias.txt
Path : C:\\SSTest\\n-alias.txt
Pattern : new.*ve<\/p>\nIgnoreCase<\/span> : True
LineNumber<\/span> : 13
Line : Alias spps<\/span> Stop-Process
Filename : s-alias.txt
Path : C:\\SSTest\\s-alias.txt
Pattern : stop<\/p>\nIgnoreCase<\/span> : True
LineNumber<\/span> : 14
Line : Alias spsv<\/span> Stop-Service
Filename : s-alias.txt
Path : C:\\SSTest\\s-alias.txt
Pattern : stop<\/p>\nPS> ss<\/span> “stop”,”new<\/span>.*ve<\/span>” *|group Pattern<\/p>\nCount Name Group