Add -AppendDate and -DateFormat parameters

Appends today's date to the remote filename before the extension
(e.g. export.txt → export_20260423.txt). Applies after -RenamePattern
if both are used. Works with -DryRun for preview.

Send-FilesToSftp.ps1

@@ -75,6 +75,14 @@
 .PARAMETER LogFile
     Path to a log file. If omitted, logs to console only.
 
+.PARAMETER AppendDate
+    Append the current date to the remote filename before the extension (e.g. export.txt → export_20260423.txt).
+    Applied after -RenamePattern if both are used. Use -DateFormat to change the date format.
+
+.PARAMETER DateFormat
+    Date format string used with -AppendDate. Default: 'yyyyMMdd' (e.g. 20260423).
+    Any valid PowerShell Get-Date format string is accepted (e.g. 'yyyy-MM-dd').
+
 .PARAMETER WinScpDllPath
     Path to WinSCPnet.dll. Default: looks in script directory, then common install paths.
 
@@ -131,6 +139,12 @@
     .\Send-FilesToSftp.ps1 -LocalPath "C:\data" -RemotePath "/archive" `
         -HostName "sftp.example.com" -UserName "svcaccount" `
         -KeyFilePath "C:\keys\id_rsa.ppk" -Recurse
+
+.EXAMPLE
+    # Upload every export.txt found in subfolders, renamed with today's date
+    .\Send-FilesToSftp.ps1 -LocalPath "C:\jobs" -RemotePath "/incoming" `
+        -HostName "sftp.example.com" -UserName "uploader" `
+        -FileFilter '^export\.txt$' -Recurse -AppendDate
 #>
 
 [CmdletBinding(SupportsShouldProcess)]
@@ -174,6 +188,10 @@ param(
 
     [switch]$DeleteAfterTransfer,
 
+    [switch]$AppendDate,
+
+    [string]$DateFormat = 'yyyyMMdd',
+
     [switch]$DryRun,
 
     [string]$LogFile,
@@ -260,6 +278,7 @@ try {
     Write-Log "Host        : ${HostName}:${Port}"
     if ($RenamePattern)      { Write-Log "Remote rename     : '$RenamePattern' → '$RenameReplacement'" }
     if ($LocalRenamePattern) { Write-Log "Local rename      : '$LocalRenamePattern' → '$LocalRenameReplacement'" }
+    if ($AppendDate)         { Write-Log "Append date       : enabled (format: $DateFormat)" }
     if ($ArchivePath)        { Write-Log "Archive to        : $ArchivePath" }
     if ($DryRun) { Write-Log "*** DRY RUN MODE - No files will be transferred ***" -Level WARN }
 
@@ -316,11 +335,15 @@ try {
         Write-Log "Files that would be transferred:" -Level INFO
         foreach ($f in $allFiles) {
             $destName        = if ($RenamePattern) { $f.Name -replace $RenamePattern, $RenameReplacement } else { $f.Name }
+            if ($AppendDate) {
+                $dateStr  = Get-Date -Format $DateFormat
+                $destName = [System.IO.Path]::GetFileNameWithoutExtension($destName) + "_$dateStr" + [System.IO.Path]::GetExtension($destName)
+            }
             $localFinalName  = if ($LocalRenamePattern) { $f.Name -replace $LocalRenamePattern, $LocalRenameReplacement } else { $f.Name }
             $remoteDir       = $RemotePath.TrimEnd('/') + ($f.DirectoryName.Substring($LocalPath.TrimEnd('\').Length) -replace '\\', '/')
             $remoteDest      = "$remoteDir/$destName"
             $sizeKB          = [math]::Round($f.Length / 1KB, 1)
-            $remoteRenameNote = if ($RenamePattern -and $destName -ne $f.Name) { " [remote name: $destName]" } else { '' }
+            $remoteRenameNote = if ($destName -ne $f.Name) { " [remote name: $destName]" } else { '' }
             Write-Log "  UPLOAD : $($f.FullName) → $remoteDest  (${sizeKB} KB)$remoteRenameNote"
 
             if ($DeleteAfterTransfer) {
@@ -398,10 +421,14 @@ try {
             }
 
             $destName   = if ($RenamePattern) { $file.Name -replace $RenamePattern, $RenameReplacement } else { $file.Name }
+            if ($AppendDate) {
+                $dateStr  = Get-Date -Format $DateFormat
+                $destName = [System.IO.Path]::GetFileNameWithoutExtension($destName) + "_$dateStr" + [System.IO.Path]::GetExtension($destName)
+            }
             $targetDir  = $RemotePath.TrimEnd('/') + $relativePath
             $targetPath = "$targetDir/$destName"
 
-            if ($RenamePattern -and $destName -ne $file.Name) {
+            if ($destName -ne $file.Name) {
                 Write-Log "Renaming: $($file.Name) → $destName"
             }