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Synchronize ftp server with a local directory

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Install Unison and curlftpfs. Mount the ftp share using curlftpfs and then perform a simple Unison sync.

For a working example, checkout the script below.


I had to do some work on a shared ftp server lately. Since I also work in trains where the internet connection can be terribly slow, I like to be able to do work offline. The easiest solution would have been to just copy the directory to my local machine and later upload my changes. But since I'm not the only one working on this server, conflicts might occur. Of course, doing collaborative work on a ftp server is a very bad idea!

Anyway, I started to look around for solutions. I immediately thought of git and figured out that it is possible to push to a ftp remote. This approach, however, fails when it comes to fetch changes from the server that were not done with git.

I started to think about rsync, but rsync is focused on one directional synchronizations.

The solution

The number one recommendation I found for a bi-directional rsync alike tool is Unison. Unison is one of those tools that are very easy to use and just work out of the box.

I wrote a very basic script that performs a synchronization of a local directory and a remote ftp server. To get started, we have to install Unison. The set up also requires curlftpfs because Unison is not able to sync over ftp.

sudo pacman -S unison curlftpfs # on Arch
sudo apt-get install unison curlftpfs # On ubuntu

That's all we need - so here is the script:

#!/usr/bin/env bash
# Requires: curlftpfs, Unison and fuse.

# Configuration:

# Mount ftp share
curlftpfs "$ftp_USER:$ftp_PASS@$ftp_HOST" "$MOUNTPOINT"

# Sync and accept defaults
Unison -auto "$MOUNTPOINT/$ftp_SUBFOLDER" "$LOCAL"

# Umount
fusermount -u "$MOUNTPOINT"

If you want to exclude files from the sync, add them into the file ~/.Unison/default.prf

ignore = Path {}