Powershell Bug in copy/move/rename when filename contains [square bracket characters]?
Solution 1
Unless you use -LiteralPath
, square brackets cause real problems with character escaping. The problem comes from PowerShell de-escaping the strings multiple times internally and using special characters for pattern matching. Getting PowerShell to correctly recognize a literal square bracket in a path string is complex.
If you're using single-quote strings, a bracket needs two backticks to escape it. If you're using double-quote strings, a bracket needs four backticks to escape it.
If you're looking for a file named MyFile[1].txt
, you need to use either:
'MyFile``[1``].txt'
or:
"MyFile````[1````].txt"
Yes, it's a pain. To see why it does this, you have to know what's going on. It's easy to do that by working backwards.
Let's say you want to get a file literally named [ab].txt
.
The wildcard pattern matching that Get-ChildItem
does means that if it gets [ab].txt
as the path, then it will look for files named a.txt
and b.txt
. So, if we want to match a literal [ab].txt
, we have to escape our brackets with the escape character: the backtick. That gives us this as the actual string of characters we want Get-ChildItem
to use for the filespec:
`[ab`].txt
However, we have to pass this filespec as a string. That means Get-ChildItem
will escape those backticks, but that's not what we want! We want literal backticks. So, we escape the backticks with backticks in our string to make sure Get-ChildItem
uses the right filespec:
'``[ab``].txt'
If we want to use double-quoted strings, then we have to escape each backtick again, as the double-quoted string will de-escape the string. And that's how you end up with this:
"````[ab````].txt"
This is why so many PowerShell functions that take filespecs have the -LiteralPath
option.
Solution 2
RenameItem
doesn't have a -LiteralPath
for some stupid reason.*
Move-Item -LiteralPath $i -destination $name
* Excuses from a co-designer of the language.
Solution 3
This finally achieved the desired result:
foreach ($i in get-childitem $folderpath) {
if ($i.mode.substring(0,1) -ne “d”) {
$name = $i.name.replace("[","_")
$name = $name.replace("]","_")
Write-Host $name -foregroundcolor “green”
[System.IO.File]::Move($folderPath+"\"+$i, $folderPath+"\"+$name)
}
}
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TTrewitt
Updated on September 17, 2022Comments
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TTrewitt almost 2 years
Please pardon a noob question, but I've been completely baffled by this one.
I have a "depositor" directory where user-submitted files arrive, and have no control over the incoming file names.
I created a parser in PS which quite successfully moves files (based on file name content) to an appropriate destination.
This works fine EXCEPT when a filename contains either "[" or "]".
Here is the "rename" pre-processor, which fails to actually rename a file containing either of the pesky bracket characters:
cd $folderpath foreach ($i in get-childitem $folderpath) { if ($i.mode.substring(0,1) -ne “d”) { $name = $i.name.replace("[","_") $name = $name.replace("]","_") Write-Host $i -foregroundcolor “blue” Write-Host $name -foregroundcolor “green” Rename-Item $i $name } }
This also fails for ren, copy, move and their cmdlet equivalents
Any insight you might be able to provide would be most welcome.
Thanks in advance . . .
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RobotHumans over 13 yearswork on you escaping-fu: techotopia.com/index.php/…
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Dennis Williamson over 13 years@TTrewitt: What version of PS?
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Philip Kendall almost 11 yearsThe link in this answer has gone 404. Anyone know of a replacement?
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Dennis Williamson almost 11 years@PhilipKendall: I fixed the link.
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AllGamer over 3 years-LiteralPath option does not work in Powershell version1 (Windows default version), if you are unable to upgrade to a newer Powershell due to workplace restrictions (Admin rights), this is by far the best solution to deal with the square brackets problem.
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velkoon about 3 yearsThis answer introduced me to the
Literal-Path
parameter I needed to use forSet-ACL -LiteralPath
that was interpreting[]
in the filename as wildcards -- Thanks (Link doesn't work anymore sadly--even on archive.org :( )