Lua

Set a Remote File's Last-Modified Time

Demonstrates the Chilkat SFtp.SetLastModifiedTimeStr method, which sets a remote file's last-modified date and time. The arguments are the remote path (or handle), whether the first argument is a handle, and an RFC 822 formatted date/time string.

Background: Of the three timestamps, the modified time is the one you most often want to set, because sync and build tools compare it to decide what is current. Stamping an uploaded file with its source's modified time keeps a mirror consistent and prevents an incremental sync from needlessly re-copying it. This is the most widely supported timestamp to set across servers.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the SFtp.SetLastModifiedTimeStr method, which sets a remote file's last-modified
-- date and time.  The 1st argument is the remote path (or handle), the 2nd (bIsHandle) indicates
-- which, and the 3rd is an RFC 822 formatted date/time string.

local sftp = chilkat.SFtp.new()

-- Connect, authenticate, and initialize the SFTP subsystem.
local port = 22
local success = sftp:connect("sftp.example.com", port)
if not success then
    print(sftp.last_error_text)
    return
end

-- 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.
local password = "mySshPassword"

success = sftp:authenticate_pw("mySshLogin", password)
if not success then
    print(sftp.last_error_text)
    return
end

success = sftp:initialize_sftp()
if not success then
    print(sftp.last_error_text)
    return
end

-- The 1st argument is a path, so bIsHandle is false.
local bIsHandle = false
local dateTimeStr = "Fri, 10 Jul 2026 20:15:30 -0600"
success = sftp:set_last_modified_time_str("subdir/report.pdf", bIsHandle, dateTimeStr)
if not success then
    print(sftp.last_error_text)
    return
end

print("Last-modified time set.")

sftp:disconnect()