In the previous tip we illustrated how you can use Select-String to find lines in raw text containing a specific word. It took some effort to extract the actual value(s) representing a given pattern:
PS C:\> $data = ipconfig | select-string 'IPv4'
PS C:\> [regex]::Matches($data,"\b(?:\d{1,3}\.){3}\d{1,3}\b") | Select-Object -ExpandProperty Value
192.168.2.112
This effort is not necessary, though, because Select-String is already using a regular expression match, and returns match objects.
PS C:\> ipconfig |
Select-String '\b(?:\d{1,3}\.){3}\d{1,3}\b' |
Select-Object -Property *
IgnoreCase : True
LineNumber : 16
Line : IPv4 Address. . . . . . . . . . . : 192.168.2.112
Filename : InputStream
Path : InputStream
Pattern : \b(?:\d{1,3}\.){3}\d{1,3}\b
Context :
Matches : {192.168.2.112}
IgnoreCase : True
LineNumber : 17
Line : Subnet Mask . . . . . . . . . . . : 255.255.255.0
Filename : InputStream
Path : InputStream
Pattern : \b(?:\d{1,3}\.){3}\d{1,3}\b
Context :
Matches : {255.255.255.0}
IgnoreCase : True
LineNumber : 19
Line : 192.168.2.1
Filename : InputStream
Path : InputStream
Pattern : \b(?:\d{1,3}\.){3}\d{1,3}\b
Context :
Matches : {192.168.2.1}
So you can use a simple Where-Object with the -like operator to do pre-filtering, identifying only the lines you are after (i.e. the ones containing the word “IPv4”), then submit a RegEx pattern to Select-String, and evaluate the results:
PS C:\> ipconfig |
# do raw prefiltering and get only lines containing this word
Where-Object { $_ -like '*IPv4*' } |
# do RegEx filtering using a pattern for IPv4 addresses
Select-String '\b(?:\d{1,3}\.){3}\d{1,3}\b' |
# get the matching values
Select-Object -ExpandProperty Matches |
# get the value for each match
Select-Object -ExpandProperty Value
192.168.2.112
