How to simply extract leading N parts of a path? - powershell

I've got a bunch of directory names and file names, some are absolute path, some are relative path. I just wish to get the 2 leading parts of each path. Input:
D:\a\b\c\d.txt\
c:\a
\my\desk\n.txt
you\their\mine
I expect to get:
D:\a
c:\a
\my\desk
you\their
Is there a convenient way in PowerShell to achieve this?

You can sometimes get your hand slapped for suggesting string manipulation as it can sometimes be "unreliable". However your test data contains 3 different possibilities. Also, never seen someone looking for the first parts from a path.
I present a simple solution the nets your desired output as you have it in your question
"D:\a\b\c\d.txt\","c:\a","\my\desk\n.txt","you\their\mine" | ForEach-Object{
($_ -split "(?<=\S)\\")[0..1] -join "\"
}
I needed to use a lookbehind since your sample output contains a leading a leading slash that you wanted to retain. It splits every string on slashes that have a non white-space character in front of them.
This would not return the correct path for UNC's. Split-Path would be the obvious choice if you only wanted a single portion of the path. I suppose you could nest the call to get 2 but at this time I am unable to find a simple way to account for all of your examples with the same logic.

Related

Powershell: Compare filenames to a list of formats

I am not looking for a working solution but rather an idea to push me in the right direction as I was thrown a curveball I am not sure how to tackle.
Recently I wrote a script that used split command to check the first part of the file against the folder name. This was successful so now there is a new ask: check all the files against the naming matrix, problem is there are like 50+ file formats on the list.
So for example format of a document would be ID-someID-otherID-date.xls
So for example 12345678-xxxx-1234abc.xls as a format for the amount of characters to see if files have the correct amount of characters in each section to spot typos etc.
Is there any other reasonable way of tackling that besides Regex? I was thinking of using multiple splits using the hyphens but don't really have anything to reference that against other than the amount of characters required in each part.
As always, any (even vague) pointers are most welcome ;-)
Although I would use a regex (as also commented by zett42), there is indeed an other way which is using the ConvertFrom-String cmdlet with a template:
$template = #'
{[Int]Some*:12345678}-{[String]Other:xxxx}-{[DateTime]Date:2022-11-18}.xls
{[Int]Some*:87654321}-{[String]Other:yyyy}-{[DateTime]Date:18Nov2022}.xls
'#
'23565679-iRon-7Oct1963.xls' | ConvertFrom-String -TemplateContent $template
Some : 23565679
Other : iRon
Date : 10/7/1963 12:00:00 AM
RunspaceId : 3bf191e9-8077-4577-8372-e77da6d5f38d

match string pattern by certain characters but exclude combinations of those characters

I have the following sample string:
'-Dparam="x" -f hello-world.txt bye1.txt foo_bar.txt -Dparam2="y"'
I am trying to use RegEx (PowerShell, .NET flavor) to extract the filenames hello-world.txt, bye1.txt, and foo_bar.txt.
The real use case could have any number of -D parameters, and the -f <filenames> argument could appear in any position between these other parameters. I can't easily use something like split to extract it as the delimiter positioning could change, so I thought RegEx might be a good proposition here.
My attempt is something like this in PowerShell (can be opened on any Windows system and copy pasted into it):
'-Dparam="x" -f hello-world.txt bye1.txt foo_bar.txt -Dparam2="y"' -replace '^.* -f ([a-zA-Z0-9_.\s-]+).*$','$1'
Desired output:
hello-world.txt bye1.txt foo_bar.txt
My problem is that I either only take hello-world.txt, or I get hello-world.txt all the way to the end of the string or next = symbol (as in the example above).
I am having trouble expressing that \s is allowed, since I need to capture multiple space-delimited filenames, but that the combination of \s-[a-zA-Z] is not allowed, as that indicates the start of the next argument.

Partial String Replacement using PowerShell

Problem
I am working on a script that has a user provide a specific IP address and I want to mask this IP in some fashion so that it isn't stored in the logs. My problem is, that I can easily do this when I know what the first three values of the IP typically are; however, I want to avoid storing/hard coding those values into the code to if at all possible. I also want to be able to replace the values even if the first three are unknown to me.
Examples:
10.11.12.50 would display as XX.XX.XX.50
10.12.11.23 would also display as XX.XX.XX.23
I have looked up partial string replacements, but none of the questions or problems that I found came close to doing this. I have tried doing things like:
# This ended up replacing all of the numbers
$tempString = $str -replace '[0-9]', 'X'
I know that I am partway there, but I aiming to only replace only the first 3 sets of digits so, basically every digit that is before a '.', but I haven't been able to achieve this.
Question
Is what I'm trying to do possible to achieve with PowerShell? Is there a best practice way of achieving this?
Here's an example of how you can accomplish this:
Get-Content 'File.txt' |
ForEach-Object { $_ = $_ -replace '\d{1,3}\.\d{1,3}\.\d{1,3}','xx.xx.xx' }
This example matches a digit 1-3 times, a literal period, and continues that pattern so it'll capture anything from 0-999.0-999.0-999 and replace with xx.xx.xx
TheIncorrigible1's helpful answer is an exact way of solving the problem (replacement only happens if 3 consecutive .-separated groups of 1-3 digits are matched.)
A looser, but shorter solution that replaces everything but the last .-prefixed digit group:
PS> '10.11.12.50' -replace '.+(?=\.\d+$)', 'XX.XX.XX'
XX.XX.XX.50
(?=\.\d+$) is a (positive) lookahead assertion ((?=...)) that matches the enclosed subexpression (a literal . followed by 1 or more digits (\d) at the end of the string ($)), but doesn't capture it as part of the overall match.
The net effect is that only what .+ captured - everything before the lookahead assertion's match - is replaced with 'XX.XX.XX'.
Applied to the above example input string, 10.11.12.50:
(?=\.\d+$) matches the .-prefixed digit group at the end, .50.
.+ matches everything before .50, which is 10.11.12.
Since the (?=...) part isn't captured, it is therefore not included in what is replaced, so it is only substring 10.11.12 that is replaced, namely with XX.XX.XX, yielding XX.XX.XX.50 as a result.

How to trim the file extensions from a filename

I have a foreach loop that gets a list of objects in Folder4 after trimming the full path where the objects reside.
Here is sample code:
$row.Path = $path.InnerText.Replace("/Folder1/Folder2/folder3/folder4/","")
Sample Output:
usp_StoredProcedurename.prc,
fn_FunctionName.udf
File.sql
The last thing I need to do is to remove any extension, ie .prc, .pdf, .udf, .sql, etc
Here is the coplete for each:
You are probably looking for the static GetFileNameWithoutExtension method. To use it, you have to pass a single file or path to it:
[System.Io.Path]::GetFileNameWithoutExtension("usp_StoredProcedurename.prc")
Depending on the actual output of $row.Path you could split the path and join them back later if you want.
Alternative, you could use a regex to remove the file extensions for alle files within your string at once:
$row.Path -replace '\..*'
Be aware that regex will remove everything after a dot.

powershell - replace line in .txt file

I am using PowerShell and I need replace a line in a .txt file.
The .txt file always has different number at the end of the line.
For example:
...............................txt (first)....................................
appversion= 10.10.1
............................txt (a second time)................................
appversion= 10.10.2
...............................txt (third)...................................
appversion= 10.10.5
I need to replace appversion + number behind it (the number is always different). I have set the required value in variable.
How do I do this?
Part of this issue you are getting, which I see from your comments, is that you are trying to replace text in a file and saved it back to the same file while you are still reading it.
I will try to show a similar solution while addressing this. Again we are going to use -replaces functionality as an array operator.
$NewVersion = "Awesome"
$filecontent = Get-Content C:\temp\file.txt
$filecontent -replace '(^appversion=.*\.).*',"`$1$NewVersion" | Set-Content C:\temp\file.txt
This regex will match lines starting with "appversion=" and everything up until the last period. Since we are storing the text in memory we can write it back to the same file. Change $NewVersion to a number ... unless that is your versioning structure.
Not sure about what numbers you are keeping
About which part of the numbers, if any, you are trying to preserve. If you intend to change the whole number then you can just .*\. to a space. That way you ignore everything after the equal sign.
Yes, you can with regex.
Let call $myString and $verNumber the variables with text and version number
$myString = "appversion= 10.10.1";
$verNumber = 7;
You can use -replace operator to get the version part and replace only last subversion number this way
$mystring -replace 'appversion= (\d+).(\d+).(\d+)', "appversion= `$1.`$2.$verNumber";