What’s highly relevant about this is that you don’t understand the permissions required for /etc/ folder.

Pacdiff needs to read and write files in /etc/ and access pacman’s cache directory /var/cache and those download- subdirectories can only be read by root, so what option to choose?

What you saw in red was related to the old mirrorlist - but the red highlighting is just vim’s syntax coloring for diff output.

If you’ve never manually edited, then the easiest option is just to OVERWRITE the old file with the .pacnew version.

You only need to merge if you added any custom mirrors.

So likely:

DIFFPROG=meld sudo -E pacdiff -s

Or do sudo pacdiff -s and choose Overwrite

After that:

sudo pacman -Syu

All sweet? come back later and mark it

Shouldn’t that rather be:

pacdiff -s

Ar least that’s what I believe I learned from this forum, although I can’t remember exactly why.

And for a better diff prog:

DIFFPROG=meld pacdiff -s

I went to open the files in kate so I could copy and paste the contents here and it looks like all of the mirrorlist files are affected:

Here’s the contents of cachyos-mirrorlist:

# STARTED AT: 2026-06-03 22:08:06.504520330 -06:00
# VERSION: 0.28.3
# ARGS: rate-mirrors --save /tmp/tmp.m0aMDTaqq6 cachyos
# MIRRORS LEFT AFTER FILTERING: 26
# JUMP #1
# EXPLORING US
# VISITED US
# BLANK ITERATION
# COUNTRY JUMPING YIELDED TOO FEW MIRRORS (0), ADDING OTHERS TO UNLABELED
# 

# TESTING UNLABELED MIRRORS
# TOO FEW BYTES LOADED https://mirror2.keiminem.com/cachyos/repo/
# TOO FEW BYTES LOADED https://mirror.keiminem.com/cachyos/repo/
# FAILED TO CONNECT TO https://archlinux.gay/cachy/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://cdn77.cachyos.org/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://mirror.zyner.org/mirror/cachyos/repo/x86_64/cachyos/cachyos.files
# TOO FEW BYTES LOADED https://us-mnz.soulharsh007.dev/cachyos/repo/
# FAILED TO CONNECT TO https://mirror.nju.edu.cn/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://cachyos.next-works.it/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://cachyos.doridian.net/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://mirror.lesviallon.fr/cachy/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://mirror.jura12.ru/repo/x86_64/cachyos/cachyos.files
# TOO FEW BYTES LOADED https://us.cachyos.org/repo/
# TOO FEW BYTES LOADED https://mirrors.lansing2600.org/cachyos/repo/
# TOO FEW BYTES LOADED https://at.cachyos.org/repo/
# FAILED TO CONNECT TO https://mirror.hb9hil.org/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://mirrors.ustc.edu.cn/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://cachyos-mirror.m1k.cloud/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://mirror.cachy-arch.ru/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://no.mirror.cx/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://wan.metrosg.ru/cachyos/repo/x86_64/cachyos/cachyos.files
# TOO FEW BYTES LOADED https://cdn.lansing2600.org/cachyos/repo/
# FAILED TO CONNECT TO https://mirror.mergedcloud.de/cachyos/repo/x86_64/cachyos/cachyos.files
# FAILED TO CONNECT TO https://ca.mirror.cx/cachyos/repo/x86_64/cachyos/cachyos.files
# TOO FEW BYTES LOADED https://mirror.krfoss.org/cachyos/repo/
# FAILED TO CONNECT TO https://nl.mirror.cx/cachyos/repo/x86_64/cachyos/cachyos.files
# TOO FEW BYTES LOADED https://mirror5.krfoss.org/cachyos/repo/
# 

# NO RESULTS TO RE-TEST
# ==== FAILED TO TEST SPEEDS, RETURNING UNTESTED MIRRORS ====
Server = https://cdn77.cachyos.org/repo/$arch/$repo
Server = https://us.cachyos.org/repo/$arch/$repo
Server = https://mirror.lesviallon.fr/cachy/repo/$arch/$repo
Server = https://no.mirror.cx/cachyos/repo/$arch/$repo
Server = https://nl.mirror.cx/cachyos/repo/$arch/$repo
Server = https://ca.mirror.cx/cachyos/repo/$arch/$repo
Server = https://mirror.zyner.org/mirror/cachyos/repo/$arch/$repo
Server = https://at.cachyos.org/repo/$arch/$repo
Server = https://mirror.mergedcloud.de/cachyos/repo/$arch/$repo
Server = https://us-mnz.soulharsh007.dev/cachyos/repo/$arch/$repo
Server = https://mirrors.lansing2600.org/cachyos/repo/$arch/$repo
Server = https://cdn.lansing2600.org/cachyos/repo/$arch/$repo
Server = https://mirror.nju.edu.cn/cachyos/repo/$arch/$repo
Server = https://mirrors.ustc.edu.cn/cachyos/repo/$arch/$repo
Server = https://cachyos.next-works.it/repo/$arch/$repo
Server = https://cachyos-mirror.m1k.cloud/repo/$arch/$repo
Server = https://cachyos.doridian.net/repo/$arch/$repo
Server = https://mirror.hb9hil.org/cachyos/repo/$arch/$repo
Server = https://archlinux.gay/cachy/repo/$arch/$repo
Server = https://mirror.jura12.ru/repo/$arch/$repo
Server = https://mirror.cachy-arch.ru/cachyos/repo/$arch/$repo
Server = https://wan.metrosg.ru/cachyos/repo/$arch/$repo
Server = https://mirror.keiminem.com/cachyos/repo/$arch/$repo
Server = https://mirror2.keiminem.com/cachyos/repo/$arch/$repo
Server = https://mirror.krfoss.org/cachyos/repo/$arch/$repo
Server = https://mirror5.krfoss.org/cachyos/repo/$arch/$repo

And here’s the contents of cachyos-mirrorlist.pacnew:

######################################################
####                                              ####
####        CachyOS Repository Mirrorlist         ####
####                                              ####
######################################################
## CDN77 (World Wide Datacenters)
Server = https://cdn77.cachyos.org/repo/$arch/$repo
## Rerouted to mirror
# Server = https://cdn.cachyos.org/repo/$arch/$repo
## Germany, disabled due Netcup issues:
## : OpenSSL SSL_read: SSL_ERROR_SYSCALL, errno 0"
# Server = https://mirror.cachyos.org/repo/$arch/$repo
## USA Mirror much thanks to corpdecker!
Server = https://us.cachyos.org/repo/$arch/$repo
## India Mirror much thanks to https://github.com/albonycal
## Disabled due issues at installation
## Server = https://mirror.albony.xyz/cachylinux/repo/$arch/$repo
## France Mirror much thanks to Antoine Viallon (aviallon)
Server = https://mirror.lesviallon.fr/cachy/repo/$arch/$repo
## Russia Mirror # Removed till sync issue is resolved
# Server = https://mirror.truenetwork.ru/cachy/repo/$arch/$repo
## Norway Mirror much thanks to QuadFeed
# Server = https://mirror.fast0ne.com/repo/$arch/$repo
## Norway,Netherlands,Canada Mirror much thanks to innoix
Server = https://no.mirror.cx/cachyos/repo/$arch/$repo
Server = https://nl.mirror.cx/cachyos/repo/$arch/$repo
Server = https://ca.mirror.cx/cachyos/repo/$arch/$repo
## Sweden Mirror much thanks to Zyner!
Server = https://mirror.zyner.org/mirror/cachyos/repo/$arch/$repo
## South Korea much thanks to Mihate Hiura!
# Server = https://mirror.funami.tech/cachy/repo/$arch/$repo
## Austria Mirror much thanks to Soulharsh!
Server = https://at.cachyos.org/repo/$arch/$repo
## Germany Mirror much thanks to Soulharsh!
## Server = https://de-nue.soulharsh007.dev/cachyos/repo/$arch/$repo
## Germany Mirror much thanks to MergedEyes!
Server = https://mirror.mergedcloud.de/cachyos/repo/$arch/$repo
## USA Mirror much thanks to Soulharsh!
Server = https://us-mnz.soulharsh007.dev/cachyos/repo/$arch/$repo
## USA Mirror & CDN mirror provided by Lansing 2600 in Lansing, MI, USA
Server = https://mirrors.lansing2600.org/cachyos/repo/$arch/$repo
Server = https://cdn.lansing2600.org/cachyos/repo/$arch/$repo
## China Mirror 10GBs much thanks to eScience Center, Nanjing University!
Server = https://mirror.nju.edu.cn/cachyos/repo/$arch/$repo
## China Mirror much thanks to University of Science and Technology of China!
Server = https://mirrors.ustc.edu.cn/cachyos/repo/$arch/$repo
## Hong Kong Mirror much thanks to Saren!
# Server = https://cachy-mirror.wtako.net/repo/$arch/$repo
## Quebec, Canada Mirror from All Things Linux
Server = https://mirror.allthingslinux.org/cachyos/repo/$arch/$repo
## Italy Mirror much thanks to NextWorks!
Server = https://cachyos.next-works.it/repo/$arch/$repo
## Italy Mirror much thanks to ironashram!
Server = https://cachyos-mirror.m1k.cloud/repo/$arch/$repo
## Bangladesh 10 GBs much thanks to Limda!
Server = https://mirror.limda.net/cachy/repo/$arch/$repo
## Finland Mirror much thanks to doridian!
Server = https://cachyos.doridian.net/repo/$arch/$repo
## Switzerland Mirror much thanks to Fabian!
Server = https://mirror.hb9hil.org/cachyos/repo/$arch/$repo
## Russia Mirror from Yandex
# Server = https://mirror.yandex.ru/cachyos/repo/$arch/$repo
## Russia Mirror much thanks to quinowell and haku.host
Server = https://archlinux.gay/cachy/repo/$arch/$repo
## Russia Mirror much thanks to jura12
Server = https://mirror.jura12.ru/repo/$arch/$repo
## Russia Mirror much thanks to cachy-arch.ru
Server = https://mirror.cachy-arch.ru/cachyos/repo/$arch/$repo
## Russia Mirror much thanks to wan666 from metrosg.ru
Server = https://wan.metrosg.ru/cachyos/repo/$arch/$repo

I wonder if this was all caused by me trying to fix my wifi issue here:

You can read this to understand what these .pacnew files are.

I already read it and I think I understand. Basically something happened on my end to change the file and now pacman detected that my file is different than the one upstream.

My current theory is that something happened to the file when I was setting regdom in an attempt to fix my issue linked above.

All I want to know is:

1. How important this is (Seems pretty important as it looks like a list of where the OS sources packages from. I may very well be wrong)
2. What is the proper way to resolve this (I’m seeing multiple answers and it seems as though doing the wrong one may screw stuff up)

Edit: If I’m understanding correctly, cachyos-rate-mirrors will rewrite the mirrorlist files with optimal server lists but won’t remove the .pacnew files. So I’m guessing I should just delete the .pacnew files then run cachyos-rate-mirrors or maybe sudo cachyos-rate-mirrors?

I just want to make sure I’m understanding this correctly before I screw something up.

I also prefer meld.

The -s flag is specifically designed to integrate with sudo more gracefully, so yes… better.

Let’s go with:

DIFFPROG=meld sudo -E pacdiff -s

• sudo -E preserves DIFFPROG environmental variables and -s is for sudo integration.
• Meld is (on Plasma) my favourite tool for the job.

edit - inserted in my OP

Open the files in kate so I could copy and paste the contents

If you use FISH, you can use functions…

function copyshow
    $argv | tee /dev/tty | wl-copy
end

so typing ‘copyshow command’ means you can simply paste

This has nothing to do with your mirrorlist files.

It is simply a product (bug?) of pacman and makepkg.

( And happens to be printed by pacdiff due to how it searches. )

I hunted down the exact cause a while ago but now do not have the links.

Anyways you can just ignore them .. or you can remove those files.

They are just fragments with no real purpose after their creation.

maclean also does this for you if you like.

PS.

Correct.

Also correct but only needed if you have not set DIFFPROG elsewhere (like /etc/environment) … and that you want meld and it is installed and so on.

Why?
pacdiff -s is all thats needed.
The DIFFPROG variable will be used if set anywhere, including on the same line.
I think you might be confusing the need of sudo E.. which is, yes, for preserving env vars .. but is more like preserving the USER environment while using sudo. It is not needed for normal pacdiff use and might cause unexpected behavior .. depending on what you were expecting exactly.

$ man sudo

[...]
     -E, --preserve-env
             Indicates  to the security policy that the user wishes to preserve their existing environment variables.  The security policy may return an error if the user does not have
             permission to preserve the environment.
[...]

I wish I could mark multiple comments as solution because it’s really the combined info from everyone that solves the issue.

I’ll just list the quotes here then mark this as the solution:

or if you want a better diff for “v” option

Then I removed the pacnew files with “r” option

this updates your mirrorlist files to be optimized

Honorable mention:

This is an amazing lightweight cleaning utility. Huge thanks for this contribution

Does this mean all the pacnews were just thrown out?

That is not how we handle those..

They need to be manually inspected and merged as needed.

(That was the whole point of using meld and all.)

I thought cachyos-rate-mirrors updated the mirrorlist files to whatever they should be anyway. That’s what it sounded like. This is so confusing

And just linking to the same page over and over isn’t going to change anything. That page doesn’t explain what to do, it just explains what things are. I already read that page. How the heck am I supposed to know if I need to merge or not? No one up until this point said anything about merging. One person mentioned overwriting and then was immediately told that’s a bad idea. These things are definitely the reason linux isn’t overtaking windows any time soon.

Maybe this will help you understanding pacnew files a little better:

https://ostechnix.com/understanding-pacnew-files-in-arch-linux/

But you know, the internet is also there for your convenience, you might want to spend some time researching these things on your own, because:

This is going to more or less be true .. I had just sort of interpreted, possibly incorrectly, the situation to include multiple pacnew files - so not just the mirrorlist.

Sorry about that, I had not noticed.

Those who understand how this works generally like it this way.
I do not want my updates overwriting my files.

There are various other guides and long threads here as well but pacnews of various forms are part of how package management works on Arch. Package management being foundational to a distro and should be among the main consideration when choosing one.

There is no single ‘you must do this’ because the nature of pacnews is they could be about any file of just about any format or relation or syntax. The point is to compare the new against your local file and decide what to incorporate.

Sorry y’all. I was a bit hangry when I wrote my previous response. I really appreciate all the help and info. This just shows I need to do a bit more research.

To be fair I picked CachyOS for the optimizations since I’m on older/outdated hardware despite knowing that Arch would probably be overwhelming for me. I guess I was hoping that Cachy would be a bit more noob friendly than other arch based distros. I suppose I did this to myself