powershell - Copy file with square brackets [ ] in the filename and use * wildcard

Question

I'm using PowerShell on Windows 7, and writing a script to copy a bunch of files from one folder structure to another. Kind of like compiling. The PowerShell Copy-Item cmdlet thinks that square brackets, [ ], are wildcards of some kind, and I am not able to escape them for some reason.

I can't use -LiteralPath, because I want to use an asterisk * wildcard since the filename has a date as part of the filename, and the date changes. The date is used as a version number.

This post was helpful, but no amount of ticks (2x or 4x per bracket) escapes the square brackets.

I am not receiving an error; PowerShell behaves the same as if I entered in the wrong filename.

This is the specific line I'm working on:

#to Fusion Server
Copy-item -Path $FSG$SW.RoomView.Notesstarter"[RoomView] Versions explained*.pdf" -Destination $FSG$containerFolder$rootFolder"Fusion Server"

And this is the whole thing:

# Compiles the Fusion packet for distribution

###############################
###########Variables###########
###############################

#folder structure
$FSG = "F:FSG"
$containerFolder = "Packet.Fusion for IT and AV Professionals"
$rootFolder      = "Fusion for IT and AV pros $(Get-Date -format “MM-dd-yyyy”)"
$subRoot1        = "Fusion Server"
$subRoot2        = "Scheduling Enhancement and Panels"
$subRoot2sub1    = "Scheduling Panels"
$subRoot3        = "SQL Server"

#source folders
$HW      = "0.Hardware"
$3SMDoc  = "0.HardwareTPMC-3SM.Documentation"
$4SMDoc  = "0.HardwareTPMC-4SM.Documentation"
$4SMDDoc = "0.HardwareTPMC-4SM-FD.Documentation"
$730Doc  = "0.HardwareTSW-730.Documentation"
$730OLH  = "0.HardwareTSW-730.OLH"
$CENRVS  = "0.HardwareCEN-RVS.Notes"

$ProjMgmt = "0.Project Management"

$SW            = "0.Software"
$RVLicensing   = "0.Software.RoomView.License"
$RVNotes       = "0.Software.RoomView.Notes"
$SQLLicensing  = "0.Softwaredatabase.SQL.Licensing"
$SQLNotes      = "0.Softwaredatabase.SQL.Notes"
$FRVMarketing  = "0.SoftwareFusion RV.Marketing"
$FRVNetworking = "0.SoftwareFusion RV.Networking"
$FRVNotes      = "0.SoftwareFusion RV.Notes"


###############################
#create the directory structure
###############################

md -Path $FSG$containerFolder -Name $rootFolder

cd $FSG$containerFolder$rootFolder
md "eControl and xPanels"
md "Fusion Server" #$subRoot1
md "Getting Started as a User"
md "Project Management"
md "RoomView Connected Displays"
md "Scheduling Enhancement and Panels" #$subRoot2
md "SQL Server" #$subRoot3

cd $FSG$containerFolder$rootFolder$subRoot1
md "CEN-RVS"
md "Licenseing Information"
md "Networking"
md "Official Documentation"
md "Prerequisites, including powerShell script"
md "Product Info"
md "Requirements"
md "Tech Info"
md "Windows Authentication to Fusion RV"

cd $FSG$containerFolder$rootFolder$subRoot2
md "Outlook Add-in"
md "Scheduling Panels" #$subRoot2sub1

cd $FSG$containerFolder$rootFolder$subRoot2$subRoot2sub1
md "TPMC-3SM"
md "TPMC-4SM"
md "TPMC-4SM-FD"
md "TSW-730"

cd $FSG$containerFolder$rootFolder$subRoot3
md "Multi-database model only"
md "SQL Licensing"

cd $FSG$containerFolder
#reset current folder


###############################
#copy the files
###############################

#Copy-Item -Path C:fso20110314.log -Destination c:fsoxmylog.log

#To the root
Copy-item -Path $FSG$ProjMgmtstarter"Fusion Support Group Contact info*.pdf" -Destination $FSG$containerFolder$rootFolder
Copy-item -Path $FSG$containerFolder"Fusion for IT and AV professionals release notes.txt" -Destination $FSG$containerFolder$rootFolder

#to eControl and xPanels
Copy-item -Path $FSG$SWxpanel.Notesstarter*.* -Destination $FSG$containerFolder$rootFolder"eControl and xPanels"

#to Fusion Server
Copy-item -Path $FSG$SW.RoomView.Notesstarter"[RoomView] Versions explained*.pdf" -Destination $FSG$containerFolder$rootFolder"Fusion Server"

What can I do to escape the square brackets and still use a wildcard filename part of the Copy-Item cmdlet?

Answer 1

In this situation, you have to use double-backticks with single quotes in order to escape the brackets. You can also use quadruple backticks when you use double quoted strings.

So the fixed line of code is:

Copy-item -Path $FSG$SW.RoomView.Notesstarter'``[RoomView``] Versions explained*.pdf' -Destination $FSG$containerFolder$rootFolder'Fusion Server'

Another good resource on file paths and wired characters etc. is to read this article: Taking Things (Like File Paths) Literally

---

EDIT

Thanks to @mklement0 for highlighting that the true cause of this inconsistency is because of a bug currently in PowerShell¹. This bug causes escaping of wildcard characters, as well as backticks with the default -Path parameter to behave differently than other parameters e.g. the -Include and -Filter parameters.

^{To expand on @mklement0's excellent answer, and comments, and other answers below:}

To better understand why we need single quotes and two back ticks in this situation; (and to highlight the bug and inconsistencies) let's run through some examples to demonstrate what is going on:

Get-Item, and associated cmdlets (Get-ChildItem, Copy-Item, etc.), handle the -Path parameter differently when dealing with a combination of escaped wildcard characters and unescaped wildcard characters *at the same time***!

TLDR: The underlying reason that we need a combination of single quotes and double backticks is how the underlying PowerShell provider parses the -Path parameter string for wildcards. It appears to parse it once for the escape characters, and a second time for the evaluation of the wildcard.

Let's go through some examples to demonstrate this odd outcome:

First, let's create two files to test with called File[1]a.txt and File[1]b.txt

"MyFile" | Set-Content '.File`[1`]a.txt'
"MyFriend" | Set-Content '.File`[1`]b.txt'

We'll try different ways to get the file. We know that Square brackets [ ] are wildcards, and so we need to escaped them with the backtick character.

We will try to get one file explicitly.

Let's start by using single quoted literal strings:

PS C:> Get-Item 'File[1]a.txt'
PS C:> Get-Item 'File`[1`]a.txt'

    Directory: C:

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2019-09-06   5:42 PM              8 File[1]a.txt

PS C:> Get-Item 'File``[1``]a.txt'

    Directory: C:

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2019-09-06   5:42 PM              8 File[1]a.txt

For single quoted strings, one backtick is all that is required to retrieve the file, but two backticks also work.

Using Double quoted strings we get:

PS C:> Get-Item "File[1]a.txt"
PS C:> Get-Item "File`[1`]a.txt"
PS C:> Get-Item "File``[1``]a.txt"

    Directory: C:  

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2019-09-06   5:42 PM              8 File[1]a.txt

For double quoted strings, as expected, we can see that we need two backticks to make it work.

Now, we want to retrieve both files and use a wildcard.

Let's start with single quotes:

PS C:> Get-Item 'File[1]*.txt'
PS C:> Get-Item 'File`[1`]*.txt'
PS C:> Get-Item 'File``[1``]*.txt'

    Directory: C:

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2019-09-06   5:42 PM              8 File[1]a.txt
-a----       2019-09-06   5:49 PM             10 File[1]b.txt

With the single quotes, when we have a wildcard character, we need two sets of backticks. One to escape the bracket, and a second backtick to escape the backtick that we used to escape the bracket when the wildcard is evaluated.

Similarly for double quotes:

PS C:> Get-Item "File[1]*.txt"
PS C:> Get-Item "File`[1`]*.txt"
PS C:> Get-Item "File``[1``]*.txt"
PS C:> Get-Item "File```[1```]*.txt"
PS C:> Get-Item "File````[1````]*.txt"

    Directory: C:

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2019-09-06   5:42 PM              8 File[1]a.txt
-a----       2019-09-06   5:49 PM             10 File[1]b.txt

With double quotes it's a little more verbose to evaluate with a wildcard. In this case, we need four sets of back ticks. For double quotes we need two backticks to escape the bracket, and another two backticks to escape the escape characters once it comes to evaluation of the star wildcard.

---

EDIT

As @mklement0 mentions, this behavior with the -Path parameter is inconsistent, and behaves differently than the -Include parameter, where only a single backtick is required to properly escape the brackets. This may be "fixed" in a later version of PowerShell.

---

^{1 As of Windows PowerShell v5.1 / PowerShell Core 6.2.0-preview.3}