README

ntools – npush & npoll

Send files and folders between two computers in the same LAN – without a shared folder, without setup, without a server.

• npoll runs on the receiver, in the folder where the files should go.
• npush runs on the sender, with the files to send as parameters.

Both find each other automatically, transfer the files and close when everything is done.

Receiver                              Sender
C:\Downloads> npoll                   C:\Projects> npush report.pdf images
npoll ver. 0.10 by Corpsman           npush ver. 0.10 by Corpsman
Info  : waiting for connections...    Info  : scanning for connections...
Info  : Receive files from : 10.0.0.5 Info  : Send files to : 10.0.0.7
Info  : report.pdf                    Info  : report.pdf
Info  : \images\holiday.jpg           Info  : \images\holiday.jpg
  100,0%  476,8 MB / 476,8 MB  ...      100,0%  476,8 MB / 476,8 MB  ...
Info  : Done: 2 file(s) received ...  Info  : Done: 2 file(s) sent ...

Contents

• How it works
• Quick start
• npush – sender
• npoll – receiver
• Exit codes
• Examples
• Firewall
• Security
• Building from source
• Integration into the file manager
• License

How it works

1. npoll listens on UDP port 8002.
2. npush opens TCP port 8002 and sends a UDP broadcast "Hello" on every network adapter (and to itself, in case npoll runs on the same machine).
3. npoll answers by opening a TCP connection to the sender.
4. For every file npush sends a header (name, size, optional MD5). npoll decides: transfer, skip (already there / -n) or resume (-a).
5. When all files are done, npush sends an end mark and both programs close.

The order in which you start the two programs does not matter, npush keeps searching until it finds an npoll (or -t runs out).

Quick start

On the receiver, open a terminal in the target folder:

npoll

On the sender, open a terminal in the folder with the files:

npush myfile.zip

While a transfer is running, the progress of the current file is shown automatically. Press ESC to abort, i to print the progress on demand (also with -q).

npush – sender

npush [options] [files / folders / masks]

If a given file or folder does not exist, npush stops immediately with an error (exit code 2).

On Linux and macOS the shell expands * itself, quote it (npush "*.pdf") if npush should do it.

npoll – receiver

npoll [options]

npoll stores the received files (including subfolders) in the current folder. File names that point outside of it (e.g. ..\..\file) are rejected.

What happens with a file that already exists on the receiver:

-a alone only compares the size. If the file on the receiver may have changed, use -md5 -a: a wrong result is detected, deleted and sent completely the next time.

Exit codes

Both programs return an exit code, so they can be used in scripts:

Examples

Send a folder and resume it later if the connection breaks:

npush -md5 -a D:\Photos\2026

Distribute an installer to three PCs, each runs npoll in its download folder:

npush -m 3 setup.exe

Keep a receiver open the whole day, but never overwrite anything:

npoll -s -n

Use in a script (Windows batch):

npush -t 30 -q -md5 backup.7z
if errorlevel 3 echo No receiver found & exit /b 3
if errorlevel 1 echo Transfer failed & exit /b 1

Firewall

On Windows the firewall asks at the first start, allow the access for the private network. With -i on npoll no UDP is needed, only TCP 8002 on the sender.

Security

ntools are made for comfort in a trusted LAN, not for security:

• There is no authentication. When npush searches for an npoll, the first npoll that answers gets the data. A connection can be hijacked during the startup.
• The transfer is not encrypted, it is as secure as plain TCP/IP.
• npoll accepts files from any npush that it finds. It only writes into the current folder (names with .. or absolute paths are rejected), but it overwrites existing files unless -n or -md5 is used.

Do not use ntools in untrusted networks.

Building from source

Requirements:

• Lazarus (tested with Lazarus 4.8 / FPC 3.2.2 on Windows; Linux and macOS work as well)
• the L-Net package (lnetbase), from the Lazarus Online Package Manager or from https://github.com/almindor/lnet

With the Lazarus IDE

1. Install L-Net: Package → Online Package Manager → lNet → Install, or open lazaruspackage/lnetbase.lpk from the L-Net sources and click Compile.
2. Open npoll/npoll.lpi, Run → Build.
3. Open npush/npush.lpi, Run → Build.

On the command line

# only once: make the L-Net package known to Lazarus
lazbuild --add-package /path/to/lnet/lazaruspackage/lnetbase.lpk

lazbuild npoll/npoll.lpi
lazbuild npush/npush.lpi

The programs are created as npoll/npoll(.exe) and npush/npush(.exe). Copy them into a folder that is in your PATH.

Project layout

Integration into the file manager

The most comfortable way: send files with a right click, start npoll with a right click into a folder. install.txt contains the original notes in German.

Windows

npush in "Send to": press Win + R, enter shell:sendto and create a shortcut to npush.exe in this folder. Now right click → Send to → npush sends the selected files.

npoll in the folder background menu: with regedit create the key

HKEY_CLASSES_ROOT\Directory\Background\shell\npoll\command

and set its default value to the full path of npoll.exe, e.g. "C:\Tools\npoll.exe". Now right click into a folder → npoll receives files into this folder.

Linux (MATE / Caja)

npush: copy send_to_npush to ~/.config/caja/scripts/, make it executable and adjust the paths in it. Now right click → Scripts → send_to_npush sends the selected files.

npoll: add the folder of npoll to your PATH (e.g. in ~/.bashrc) and start npoll in a terminal in the target folder.

Binary download

Download prebuilt binaries of npoll and npush for Windows64 and Linux64 from the latest GitHub release:

https://github.com/PascalCorpsman/ntools/releases/latest

License

See license.md: Postcardware or modified LGPL, as you like.