這是我擁有的一個腳本，它在螢屏上顯示時查找 wifi 網路的名稱和密碼：
$CmdL = @("Command1", "Command2", "WIFI NAME")
Trap [System.Management.Automation.RuntimeException] {
Write-Color "No such WiFi exists" -Color "Red"
Continue
}
$S = $Null
$E = Get-AllWifiPasswords
Write-Host
$S = ($E | sls ($CmdL[2])).ToString().Trim()
Write-Color $S -Color "Green"
Write-Host
但是，如果找不到網路名稱，則會在末尾添加一個尾隨換行符：
(newline)
No such WiFi exists
(newline)
(newline)
我不知道為什么會有換行符，因為它不應該存在。如何洗掉它以便錯誤輸出如下：
(newline)
No such WiFi exists
(newline)
uj5u.com熱心網友回復：
額外的換行符來自這樣一個事實，它Write-Color $S -Color "Green" 也在發生錯誤時執行，在這種情況下$S沒有值，導致空行。
雖然trap仍然支持，在try/ catch/finally宣告引入更高版本提供了更多的靈活性和控制流的清晰度：
$CmdL = "Command1", "Command2", "WIFI NAME"
$S = $Null
$E = Get-AllWifiPasswords
Write-Host
try {
# If the next statement causes a terminating error,
# which happens if the `sls` (`Select-String`) call has no output,
# control is transferred to the `catch` block.
$S = ($E | sls ($CmdL[2])).ToString().Trim()
Write-Color $S -Color "Green"
}
catch {
Write-Color "No such WiFi exists" -Color "Red"
}
Write-Host
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