How to use 'Select-String' to filter lines from an output

Question

(first of all, I have searched SO,internet,youtube, for half an hour and didn't came with proper answer so I ask here)

I'm coming from the realm of routers and helpesk when you can simply filter string\s from an output with

"| include" (cisco) or "| findstr" (windows) like this:

I found out, on powershell we use 'Select-String' with the 'Pattern' switch.

For instance, i want to print out all the lines which contain the word 'Suffix' but it doesn't seem to work. What is the correct way, and can I use it without the need to creat a variable.

Can you include the text from the pictures in your question? — js2010, Oct 03 '20 at 12:44
PLEASE, don't post images of code/errors/sample-data. why? lookee ... Why not upload images of code/errors when asking a question? - Meta Stack Overflow — https://meta.stackoverflow.com/questions/285551/why-not-upload-images-of-code-errors-when-asking-a-question — Lee_Dailey, Oct 03 '20 at 13:26

score 3 · Answer 1 · answered Oct 03 '20 at 11:31

3

Thank you both for clearing it out to me that the method retures objects in the form of array.

Unfortunately, I found working with 'Where-Object' and 'Select-Object' is complicated for this one time viewing purpose, so I converted the output to a string with the 'Out-String -Stream' cmdlet.

Get-NetIPAddress | Out-String -Stream | Select-String -Pattern "127.0.0.1"

It did the job well.

answered Oct 03 '20 at 11:31

Omer Meister

43
1
8

You do know that `Select-String` defaults to using a regex pattern if switch `-SimpleMatch` is not used, and that the pattern "127.0.0.1" contains dots, which have special meaning in regex (_any character_), do you? Without escaping those dots, a value of say "127X0Y0Z1" would also pass.. Rule of thumb: don't stringify an object to get one of its properties – Theo Oct 04 '20 at 11:49
Thank you for the important notice, I didn't took the time to lookup for the switches actions. @Theo – Omer Meister Oct 05 '20 at 20:28

score 0 · Answer 2 · answered Oct 03 '20 at 10:47

Select-String is a cmdlet to find text in strings and files.
Get-NetIPAddress does not output a string, but an array of (CimInstance) objects.

To select only certain values from this array, you can pipe the result through to Select-Object like for instance

Get-NetIPAddress | Select-Object Suffix*

which outputs something like:

SuffixOrigin
------------
        Link
        Link
   WellKnown
        Link
        Dhcp
   WellKnown

This output on its own is probably not very usefull though..
You might want to end up with selecting a few more properties like with

Get-NetIPAddress -AddressFamily IPv4 | Select-Object IPAddress, InterfaceAlias, Suffix*

flaxel · Answer 3 · 2020-10-03T11:38:05.260

The cmdlet Get-NetIPAdress returns an array of objects which can be filter with the cmdlet Where-Object. But the disadvantage is that you must choose the field for the filtering. There is a short example in the documentation. Or you can use the cmdlet Select-Object:

Get-NetIPAddress | Select-Object *fix*

Otherwise you can also use the command ipconfig to be able to filtering your output:

ipconfig | Select-String -Pattern "fix"

How to use 'Select-String' to filter lines from an output

3 Answers3