Remove some characters from filename using powershell - file

Question

I have a 100 files Which are named for instance: (Without quotes)
"Managing and Improving Own Learning [L3] {CBA849}" and
"Note-taking and Note-making [L3] {CBA851}"
I would like to rename it in a such way that it only shows "CBA849" and "CBA851" and remove anything else.
Another words I would like to keep file code inside {....} curly brackets.
Is there a way we can implement this? (Note: It's not replacing characters)
Thanks

Answer 1

Rename-Item -LiteralPath $path ([regex]::match($path, '{(.+)}')).Groups[1].Value
You need -LiteralPath because the filename contains brackets.
[regex]::match($path, '{(.+)}') matches the curly braces and their contents, and captures the contents into a match group. .Groups[1].Value returns the value of the first (and in this case, the only) match group.
This assumes that all the files are named in the format shown in the question. If it's possible that there might be curly braces elsewhere in the name, change the regex {(.+)} to {(.+?)}$.

Answer 2

I'd personally use a Regex match:
GCI $path | ?{$_.Name -match "(?:.*?{)(.*?)(?:})(\..*)?$"}|%{$_.MoveTo("$($_.Directory)\$($matches[1])$($matches[2])")}
Edit: As Adi Inbar says, I have created an overly complicated RegEx pattern. Simplified as he suggested (though still allowing for extensions) is a revised answer:
GCI $path | ?{$_.BaseName -match "{(.*?)}$"}|%{$_.MoveTo("$($_.Directory)\$($matches[1])$($_.Extension)")}
Edit: Ok, here's the breakdown...
GCI is short for Get-ChildItem, it pulls a listing of the directory specified, but I think you probably figured that one out.
Then it pipes to a Where{} clause(? is an alias for Where). It matches the BaseName of the files and folders provided by the GCI command. The BaseName property is actually one generated by PowerShell that takes the name of the file, extension and all, and then removes the extension (with preceding period) from it so if the file name is Sample.txt then it provides you with Sample as the BaseName.
It matches that against a RegEx (short for Regular Expression) pattern. If you don't know what RegEx is, please feel free to look it up and read up on it (Google is your friend). The basics is that it matches a pattern instead of actual text. In this case the pattern is anything at the end of the file name that is between curly braces.
Past that it enters a ForEach loop (I used the % alias for ForEach). For each file that matched the RegEx pattern it performs the MoveTo() method for that file. The location that it is moving it to is that file's current directory (gotten with $.Directory), followed by a backslash, followed by $Matches[1] (I'll get to that in a second), and then the original extension of the file (gotten with $.Extension). Now you'll see I wrapped the Directory and Extension in a sub-expression $() because with string extrapolation (how it auto-magically expands variables if you put them within double quotes) if you try to specify a property of a variable you have to put it in a sub-expression. Otherwise it tries to expand just the variable itself, and shows the .Whatever property name in plain text.
Lastly, $Matches is an automatic variable that is populated when you make a match with a few things (such as <something> -match <something else> like we did in the Where clause). The first record of it is the whole string that was matched <something>, and then the next records are the matches based on <something else>.
I hope that clears it all up for you. If you have specific questions let me know. If this answer resolved your question please mark it as accepted.

Answer 3

$f=gi $filepath;
$f.MoveTo($f.fullname.Replace($f.name,$f.name.substring($f.name.indexof("{")+1,($f.name.indexof("}")-1)-$f.name.indexof("{"))+$f.extension))
Get the File you're looking to rename as a [System.IO.FileInfo] object using get-item (gi).
Once you have the file object in $f the script is doing:
MoveTo
$f.FullName: The full path of the existing file (C:\some\dir\Test {ABC123}.txt)
Modify FullName to be the new filename by using the Replace function to replace the old filename ($f.name), with the desired name
The Substring function of the filename will allow you to get just the string between the curly braces.
Find the index of the OpenCurlyBracket within the name string
Find the index of the CloseCurlyBracket within the name string
Once the text between the curly brackets is identified with the Substring function, append the file extension to the new filename