Powershell parsing file names

Using multiple patterns in combination with named capture groups makes it a breeze to extract the groups even when the positions of the groups differ.

The second regex is similar, but with the groups in different order. Select-String also has a Context parameter which accepts an array of one or two numbers specifying the number of lines before and after a match that should be captured.

All text parsing techniques in this post can be used to parse information from the context lines. The result object has a Context property, that returns an object with PreContext and PostContext properties, both of the type string[]. The pipeline support of Select-String makes it different from the other parsing tools available in PowerShell, and makes it the undisputed king of one-liners.

I would like stress how much more useful Select-String becomes once you understand how to get to the parts of the matches. We have looked at useful methods of the string class, especially how to use Substring to get to text at a specific offset.

We also looked at regular expression, a language used to describe patterns in text, and on the Select-String cmdlet, which makes heavy use of regular expression. Next time, we will look at the operators -split and -match , the switch statement which is surprisingly useful for text parsing , and the regex class.

Staffan Gustafsson, StaffanGson , github. Comments are closed. HI Steve excellent article. As always, I try to avoid string parsing and use the object oriented cabilities of PowerShell and using XML files as input to obtain matches via XPath. So this is very helpful in that respect. In the past, I have created type extensions for System. String which is really cool as well. PowerShell Documentation. Sydney Smith. Andy Schwartzmeyer Senior Software Engineer.

Travis Plunk Senior Software Engineer. This is the first post in a three part series. Part 1 : Useful methods on the String class Introduction to Regular Expressions The Select-String cmdlet Part 2: The -split operator The -match operator The switch statement The Regex class Part 3: A real world, complete and slightly bigger, example of a switch-based parser A task that appears regularly in my workflow is text parsing.

The substring starts at a specified character position and continues to the end of the string. Substring int startIndex, int length Retrieves a substring from this instance.

The substring starts at a specified character position and has a specified length. IndexOf string value Reports the zero-based index of the first occurrence of the specified string in this instance. IndexOf string value, int startIndex Reports the zero-based index of the first occurrence of the specified string in this instance. The search starts at a specified character position. LastIndexOf string value Reports the zero-based index of the last occurrence of the specified string in this instance.

If the line starts with "username", split the line using colon as delimiter, grab the second item 0-relative so the second item is number one into a variable. Then, add the object to the array. I suggest you to change your format to CSV instead, and then it's very trivial. Just use Import-Csv. Right now you could do something a long of the lines, it assumes valid text file, no empty lines:. I would use regexes to get at the data example below , and you may need to tweak the regexs to extract the names and numbers, because I only had your small sample to go on and I have made some assumptions like no spaces in the names and numbers.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Parsing a text file in PowerShell Ask Question. Asked 6 years, 8 months ago. Active 2 years, 10 months ago. Viewed 6k times. I have a text file with multiple users in the exact format : username:t-Hancock phoneNumber: username:a-smith PhoneNumber: username:r-Byer phonenumber: I am trying to get all these users into an object with two properties name and phone number.

How could this be done? Improve this question. Peter Mortensen Can you show what you have tried? You will usually get a better response if you do — Graham Gold. Now, to be able to parse the files, we will want to use the switch command. The switch command in PowerShell is similar in function to the same command in other languages. You can think of it as being capable of stacking multiple IF statements together. This is what goes where we have the comment " Processing code goes here" in the previous block.

Note that for each pattern of a regular expression in single quotes followed by the curly braces, we have an evaluation. If I was looking for Users, I could add another line to parse this as well. Once all this is done, all that's left to do is write out what was captured. How could we split a 30 gig Unix text file into N text files split on a line width of characters?

You should probably point out that this method is going to consume a large amount of system memory if ran on a large directory, which if you find yourself writing a script to parse files in a directory, chances are you doing it because the directory is huge.

Parsing all the files in a directory using PowerShell. Use a foreach to loop through all the files in a directory. This method allows us to easily track the file name so we can report our findings by file. We will need to tell the Switch command exactly where to parse, so we'll put together the full file path. ArrayList; Use a foreach to loop through all the files in a directory.