PowerShell Issues with getting string from file

Question

Problem

I am working on an automated version control script in powershell and I hit a snag where I am trying pull a line of text from an AssemblyInfo.cs file. However, I can't seem to get it to work as expected despite all my efforts.

After many trial and errors to achieve the results intended, I have come to find the following to get close to what I'm trying to achieve:

# Constants
$Assembly = Get-Item "C:\generalfilepath\*\Assembly.cs"
$regex = '(?<!\/\/ \[assembly: AssemblyVersion\(")(?<=\[assembly: AssemblyVersion\(")[^"]*'

$CurrentVersion = GC $Assembly
$CurrentVersion = $CurrentVersion -match $regex

Write-Host "CurrentVersion = $CurrentVersion

I am expecting to see: CurrentVersion = 1.0.0.0 or something similar, but what I get is: CurrentVersion = [assembly: AssemblyVersion("1.0.0.0")]

I have been searching all over for examples on how to properly utilize regex with PowerShell, but I have not really found anything that contains more than the regex itself... As such, I was hoping someone here could assist me in either steering me in the right direction or point out what I am doing wrong.

Question

Despite the use of the regex filter, I'm getting the entire line instead of just the value I want. How do I ensure the variable stores ONLY the target value using the lookbehind and lookahead regex filters?

Get-Content returns an array of lines, -match on an array of lines filters it for the lines which match the regex. It's not clear if you're expecting one file, since you use a wildcard in the path, but however you do it, you need to reference $Matches after using -match to get the match details. Probably Get-Content -Raw to get a single string, and -match and then $matches[1] — TessellatingHeckler
– TessellatingHeckler, Commented Nov 13, 2017 at 23:19

Moerwald · Accepted Answer · 2017-11-14 07:03:40Z

1

You can try:

C:\> ([string] (Get-Content \AssemblyInfo.cs)) -match 'AssemblyVersion\("([0-9]+(\.([0-9]+|\*)){1,3}){1}"\)'
True

Afterwards the result shall be store in $Matches[1]

C:\> $Matches[1]
6.589.0.123

Be aware to cast the results of Get-Content to [string] otherwise $Matches will be $null. See this answer for a complete description.

If you want to use a more "greedy" regex like ^\[assembly: AssemblyVersion$"([0-9]+(\.([0-9]+|\*)){1,3}){1}"$ which also includes a check (^\[assembly:) that the string starts with [assembly you've to walk through the [string[]] array Get-Content returns:

> gc .\AssemblyInfo.cs | % { $_ -match '^\[assembly: AssemblyVersion\("([0-9]+(\.([0-9]+|\*)){1,3}){1}"\)' }

> $Matches[1]
6.589.0.*

Hope that helps.

edited Nov 14, 2017 at 7:03

answered Nov 14, 2017 at 6:41

Moerwald

11.4k10 gold badges54 silver badges92 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Brandon Over a year ago

Thank you. This cleared things up greatly. I was totally confused and was frustrated because I felt like a hamster on a wheel, going nowhere fast. Thank you for the explanation and the link to further information.

Collectives™ on Stack Overflow

PowerShell Issues with getting string from file

Problem

Question

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

Problem

Question

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related