PowerShell中GCI加Recurse与通配符返回结果异常问题

Great question—this behavior boils down to the tricky interaction between PowerShell's ** recursive wildcard and the -Recurse parameter. Let's break it down step by step:

First, clarify the core behaviors #

• The ** wildcard (PowerShell 3.0+) is designed to match any depth of subdirectories under a target path. By default, it targets directories, not files.
• The -Recurse parameter tells Get-ChildItem to traverse all levels of subdirectories under the specified path and return all contained items.

Walk through your two scenarios #

Scenario 1: a.txt is directly in dir1 #

Your directory structure:

TestRecurse
|---b.txt
|---dir1
|------a.txt

When you run gci 'C:\temp\TestRecurse\**' -Recurse:

1. First, PowerShell resolves the ** wildcard, which matches the only direct subdirectory of TestRecurse: dir1.
2. Here's the key quirk: when -Recurse combines with ** that only matches direct first-level subdirectories, PowerShell implicitly includes the parent directory (TestRecurse itself) in the traversal. This happens because ** can technically match "zero levels of subdirectories" (i.e., the current directory).
3. The command ends up traversing two paths:
   • TestRecurse: returns b.txt (from the root) and a.txt (from dir1)
   • dir1: returns a.txt
4. After deduplication, you get both b.txt and a.txt.

Scenario 2: a.txt is in dir1\dir2 #

Your updated directory structure:

TestRecurse
|---b.txt
|---dir1
|------dir2
|---------a.txt

Running the same command:

1. Now, ** matches two subdirectories: dir1 and dir1\dir2 (since ** targets all depth levels).
2. When -Recurse kicks in, it only traverses the directories explicitly matched by **—the implicit inclusion of the parent TestRecurse directory no longer applies.
3. The command traverses:
   • dir1: recurses into dir2 and returns a.txt
   • dir1\dir2: directly returns a.txt
4. Since the parent TestRecurse isn't being traversed, b.txt never shows up in the results.

Wrap-up #

This isn't a bug—it's an edge case of how PowerShell handles the combination of ** and -Recurse. The implicit parent directory inclusion only triggers when ** matches only direct, first-level subdirectories. Once ** matches deeper subdirectories, that implicit behavior drops off, and only the matched subdirectories are traversed.

内容的提问来源于stack exchange，提问作者Brady S