PowerShell中Ahsay备份脚本的备份类型识别搜索异常求助

Let's break down why your current logic is misbehaving and fix it step by step.

The Root Cause #

Your variable $LogType isn't a single string—it's an array of strings, where each element is a line from your log file (thanks to Get-Content returning lines as separate array items).

PowerShell's comparison operators like -like and -notlike work differently on arrays than they do on single strings:

• $LogType -notlike "*Database*" returns all lines that don't contain "Database". Since most of your log lines don't have that keyword, this expression evaluates to $true in a boolean context (because it's a non-empty array).
• $LogType -like "*file list*" returns the lines that do contain "file list"—which exists in your log, so this also evaluates to $true.

When you combine these with -and, both conditions are true, so your if branch runs even though the log contains "Database"—exactly the behavior you're trying to avoid.

Fixes to Get the Logic Right #

You need to check whether the entire log content meets your criteria, not individual lines. Here are two clean approaches:

Option 1: Convert the Log Array to a Single String

First, join all log lines into one string, then check for the presence/absence of your keywords against the whole text:

get-childitem -Exclude *Scheduler*, *SystemTray*, *Archived*,*System* | select -last 1 | Get-Content -totalcount 13 -outvariable LogType

# Combine array into a single string with line breaks preserved
$fullLog = $LogType -join "`n"

# Now check the entire log content
if ($fullLog -notlike "*Database*" -and $fullLog -like "*file list*") {
    # Your file-only backup handling logic here
}

You can also use -match instead of -like if you prefer regex (e.g., $fullLog -notmatch "Database"), which works the same way for simple substring checks.

Option 2: Check for Existence of Keywords in the Array

If you want to avoid string concatenation, you can explicitly check whether any line contains each keyword:

get-childitem -Exclude *Scheduler*, *SystemTray*, *Archived*,*System* | select -last 1 | Get-Content -totalcount 13 -outvariable LogType

# Check if any line contains "Database" or "file list"
$containsDatabase = $LogType | Where-Object { $_ -like "*Database*" } | Select-Object -First 1
$containsFileList = $LogType | Where-Object { $_ -like "*file list*" } | Select-Object -First 1

# Only run the branch if NO Database lines exist AND File List lines do exist
if (-not $containsDatabase -and $containsFileList) {
    # Your file-only backup handling logic here
}

This is efficient because it stops searching as soon as it finds the first matching line (thanks to Select-Object -First 1).

Quick Note on Case Sensitivity #

If your logs might have variations in capitalization (e.g., "File List" instead of "file list"), you can adjust the checks:

• For -like, PowerShell is case-insensitive by default—add the -CaseSensitive flag only if you need exact case matching.
• For -match, use the (?i) regex modifier: $fullLog -match "(?i)file list"

Testing this with your sample log: since there's a line containing "Database", $containsDatabase will have a value, so -not $containsDatabase becomes $false, and the if branch won't run—exactly what you need.

内容的提问来源于stack exchange，提问作者Tom Halverson