PowerShell

Check if a Remote File or Directory Exists

Demonstrates the Chilkat SFtp.FileExists method, which checks a remote path and returns an integer describing what is there. The first argument is the remote path and the second (followLinks) selects whether a symbolic link is followed to its target. The return value is -1 on error, 0 if nothing exists, 1 for a file, 2 for a directory, 3 for a symbolic link, and higher values for special entry types.

Background: This returns more than a yes/no because "does it exist" usually comes with "and is it the kind of thing I expect" — a job that means to write a file should notice if a directory already occupies the path. The followLinks flag decides whether a symbolic link is reported as a link (3, only when not following) or transparently resolved to its target's type. Always handle the -1 case: it means the check itself failed, which is different from the path not existing.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  Demonstrates the SFtp.FileExists method, which checks a remote path and returns an integer
#  describing what is there.  The 1st argument is the remote path and the 2nd (followLinks)
#  selects whether a symbolic link is followed to its target.

$sftp = New-Object Chilkat.SFtp

#  Connect, authenticate, and initialize the SFTP subsystem.
$port = 22
$success = $sftp.Connect("sftp.example.com",$port)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  Normally you would not hard-code the password in source.  You should instead obtain it
#  from an interactive prompt, environment variable, or a secrets vault.
$password = "mySshPassword"

$success = $sftp.AuthenticatePw("mySshLogin",$password)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$success = $sftp.InitializeSftp()
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  When followLinks is $true, a symbolic link is followed and the target's type is returned.
$followLinks = $true
$result = $sftp.FileExists("subdir/report.pdf",$followLinks)

#  Interpret the return value.
if ($result -eq -1) {
    $($sftp.LastErrorText)
    exit
}

if ($result -eq 0) {
    $("The path does not exist.")
}

if ($result -eq 1) {
    $("A regular file exists.")
}

if ($result -eq 2) {
    $("A directory exists.")
}

#  Other possible values: 3 = symbolic link (only when followLinks is $false), 4 = special
#  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

$sftp.Disconnect()