Combine two regex in PowerShell

Question

This is the data I am trying to parse:

10.186.128.0/20 172.17.128.161 0 65000 8788

10.186.128.0/20 172.17.128.161 0 65000 878

10.186.128.0/20 172.17.128.161 0 65000 87

Ideally the output should match the IP address from the beginning of the line and also last 2 or 3 or 4 digits. Example desired output:

10.186.128.0/20 8788

10.186.128.0/20 878

10.186.128.0/20 87

I have regex that will match the IP address "10\.\d*\.\d*\.\d*\/\d\d"

And then I have second regex that will match the last 2 or 3 or 4 digits " \d{4}$| \d{3}$| \d{2}$"

Question is how to combine those two regex expressions in PowerShell to achieve desired result?

Thanks

Maybe $s -replace '^(10(?:\.\d+){3}/\d+)\s.*\s(\d+)$', '$1 $2'? Or do you mean the text contains lines that need to be extracted first? — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 26, 2019 at 13:54
If you are trying to match IP adresse, there will never be more than 3 digit between dots, and never less than 1. You should change your regex to 10\.\d{1,3}\.\d{1,3}\.\d{1,3}\/\d{2} — Nicolas
– Nicolas, Commented Nov 26, 2019 at 13:58
Cool. Thanks. I modified my IP matching regex. However how to achieve the desired outcome of getting the IP and also the last 2 or 3 or 4 digits in the string? — Jozef Trubac
– Jozef Trubac, Commented Nov 26, 2019 at 14:02
I've created a regex 101 for you to test more cases, basically, i've added a space an a match for 2 to 4 digits. — Nicolas
– Nicolas, Commented Nov 26, 2019 at 14:10
Select-String '(?m)^(10(?:\.\d+){3}/\d+)\s.*\s(\d+)\r?$' -input $txt -AllMatches | Foreach {$_.matches} | Foreach {$_.groups[1].value + " " + $_.groups[2].value}? Note the $txt here is a multiline string input. It outputs expected result in PS 6.1.3 — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 26, 2019 at 14:21

Wiktor Stribiżew · Accepted Answer · 2019-11-26 14:53:09Z

1

You may use

Get-Content $filepath | Select-String '^(10(?:\.\d+){3}/\d+)\s.*\s(\d+)$' -AllMatches | Foreach-Object {$_.Matches} | Foreach-Object {$_.Groups[1].Value + " " + $_.Groups[2].Value}

The ^(10(?:\.\d+){3}/\d+)\s.*\s(\d+)$ regex - see its online demo - matches:

^ - start of string
(10(?:\.\d+){3}/\d+) - Group 1: 10, then three repetitions of a dot and any 1+ digits and then / and 1+ digits
\s.*\s - a whitespace, any 0+ chars other than newline as many as possible and a whitespace
(\d+) - Group 2: 1+ digits
$ - end of string.

So,

Get-Content $filepath reads the file
Select-String '^(10(?:\.\d+){3}/\d+)\s.*\s(\d+)$' -AllMatches gets all matches from the file that it gets by reading the file line by line
Foreach-Object {$_.Matches} grabs all matches one by one
Foreach-Object {$_.Groups[1].Value + " " + $_.Groups[2].Value} concats Group 1 and 2 values.

answered Nov 26, 2019 at 14:53

Wiktor Stribiżew

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1 Comment

Jozef Trubac Over a year ago

This is exactly what I was looking for. Thank you.

AdminOfThings · Accepted Answer · 2019-11-26 15:20:47Z

1

Using -split seems much simpler if all of your data is consistently in the posted format.

Get-Content -Path file.txt |
    Foreach-Object { [string]($_ -split ' ')[0,-1] }

Explanation:

-split uses regex matching to split a string into an array of strings. Here the string is split based on a single space. [0,-1] selects the first (index 0) and last (index -1) elements of the array.

[string] casts the two array elements as a string. Since PowerShell automatically joins two items with a space when they are cast as a string, this is just merely a shortcut.

answered Nov 26, 2019 at 15:20

AdminOfThings

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Comments

score 1 · Accepted Answer · 2019-11-26 17:53:39Z

1

If a quick way to modify the string is all that's needed
a simple replace with one of these two regex :

$string -replace '(?<=\b10\.\d{0,3}\.\d{0,3}\.\d{0,3}/\d{2}).*(?=[ \t]\d{1,4}\b)', ''

or

$string -replace '(?m)(?<=^[ \t]*10\.\d{0,3}\.\d{0,3}\.\d{0,3}/\d{2}).*(?=[ \t]\d{1,4}[ \t]*$)', ''

edited Nov 26, 2019 at 17:53

answered Nov 26, 2019 at 17:47

user12097764

3 Comments

Jozef Trubac Over a year ago

This solution would effectively remove the part that I am looking to retrieve. The solution provided by Wiktor Stribiżew works perfectly fine so it should be marked as the right answer IMHO.

user12097764 Over a year ago

@JozefTrubac - The resulting string is the IP address from the beginning of the line and also last 2 or 3 or 4 digits.

user12097764 Over a year ago

@JozefTrubac - I never read or look at other answers as I consider myself an expert. See Possible duplicate.

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