As we all know, file copying on Linux has long relied on the classic cp command, which remains reliable but offers little feedback and limited control over long or complex operations.
To address this, a promising new Rust-based command-line tool called cpx emerge, designed as an alternative rather than a replacement, that approaches the same task with a focus on performance, visibility, and configurability.
It targets scenarios where large directory trees, interrupted transfers, or the need for detailed progress reporting make standard tools less convenient to use. The project is currently Linux-only and leverages modern kernel features to improve copy throughput and reliability.
New Linux util.
looks inside
Non-copyleft license
I appreciate that it’s not trying to replace
cpbut the lack of copyleft is always disconcerting.yeah, like, supposedly it can be hard to use GPL with some rust dependencies, but the MPL is right there as a decent compromise.
how can it be hard? permissive licenses are compatible to the GPL, the opposite not though
Static linking makes things difficult. I’m not sure what the details are, that’s just what I’ve heard from Rust developers.
Because of static linking, a single GPL dependency turns the entire resulting binary into a GPL licensed one, so yeah just use something like the MPL in that case (Or EUPL, which I hear is similar)
LGPL has the same issue, since it only provides an exception for dynamic linking. But honestly that’s all an issue for lawyers and judges to sort out (I bet you could win in court with an argument that dynamically linking to GPL is actually fine).
I like and use rust, and I actively try to use permissive licenses for libraries and copy left for binaries. Just makes sense in my head.
I like and use rust, and I actively try to use permissive licenses for libraries and copy left for binaries. Just makes sense in my head.
I always find choosing a license confusing.
If you’re up for it, I would love to read why you use this guideline.
I want people to use the software I write, and people don’t want dependencies in their projects that are gpl because you either need to change your project to gpl or go through a very tedious process of providing object files for the entire project. That’s why I use mit for libraries.
However, I don’t want to allow companies to just take my finished binaries and resell them as their services, so I use GPL for binaries and apps. They are free to reimplement the app using the libraries, but I at least want them to work for it a little.
Also, I have found it easier to get contributions to projects that are licensed under mit than gpl, though this might just be insufficient sample size.
Food for thought. Thank you!
What’s the risk here though, a company like Amazon makes a closed source version of it?
If it was a file format library, or something like a web server I’d get it. But stuff like
cpare effectively just userspace wrappers around kernel APIs.
MIT License 🤢🤮
What’s wrong with the MIT License? It’s one of the most permissive licenses out there. I don’t see how a copy-left clause like others are saying would change things. If someone wants to compile this in to their own proprietary file explorer or something, who cares? Everyone still has access to the original.
What’s wrong with the MIT License?
Good question.
Failure to copyleft contributes to “embrace extent extinguish”, which many of us feel is a constant threat to the ecosystem of our favorite tools.
For example, Google can make a better expanded XMPP client, and keep extending it until the open XMPP clients are no longer compatible - drawing most of the userbase away from the free open ecosystem. (Source: I fell for that shit, and I lost track of dear friends who I used to regularly chat with over XMPP.)
MIT license also risks security patches being written by big corporations for their own use, and not getting contributed back to the commons.
I’m not really sure these risks particularly apply for a ‘cp’ variant, honestly.
But I’m onboard now with not making anything unnecessarily MIT license.
Google could have done that from the spec though. Google is doing that with chromium despite the source being entirely available
even agpl wouldn’t protect this tool in most cases if a company didn’t want to contribute back, since it’s probably just used in server side scripts and such. also companies aren’t required to upstream stuff, just make source available, which means hard to discover ftp site with a pile of code.
sure something more copyleft is better for large, more commercial projects, but this in particular probably gets more patches from the extra use in the rust community from MIT than they would forcing companies to open source changes
Welcome to rust where MIT is just recommended yet everyone does use it for licensing.
I’m aware that they are wrong
What’s wrong with rsync?
It’s a damn pain to remember all the flags. How many flags can a program friggin have? I’m always afraid that some flag I enter will reverse the sync and delete everything in the source folder because the target is empty.
I use rsync only when all params have been reseasrched and tested. cpx presumably just requires
cpx - r source targetinstead of 5 rsync flags.The only one you need is -a. -avz if you want verbose and compression.
I just looked it up and - x means one filesystem. But does - v give you a progress bar or just a lost of stuff copied?
IIRC rsync also treats the trailing slash in a special manner that I always have to look up.
Ha. I meant z. I guess I was getting mixed up with tar.
No slash means the directory. Slash means the items in the directory.
I’m always afraid that some flag I enter will reverse the sync and delete everything in the source folder because the target is empty.
A version of
rsyncwithout this risk would be a killer app. Haha.
That’s probably the next wheel some overzealous Rust dev will reinvent.
Too many letters to type obvi! /s
I’ve had cp aliased to rsync with my flags for years. It seems like a lot of newcomers try to “fix” stuff before they really understand what’s available. Or they just like to play around with different programming languages. Which is fine, but usually it’s not really interesting to me.
you seem to have added a condescending comment before you understood the goals. 2-5x speedup over rsync (their benchmarks, but still) seems significant on its own, and an interface that doesn’t require aliasing to be useful is also nice
Nope, thanks for projecting though. I just didn’t mention the multi-threaded because, again, it doesn’t speed up anything. Transfer speed has always been the bottleneck, unless you’re talking about heavy data-center type use. Like I said, if it’s interesting to you, go for it. I don’t see a need to reinvent the wheel on core utilities.
wym doesn’t speed anything up? they have a very thorough page of benchmarks
apparently gets a 2-5x speedup over rsync +nicer interface
