The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

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post hole digger: Mar 21, 2011

There it is... thank you. I looked at the module page but I glossed right over that :tipshat:

# ? Oct 21, 2017 00:16

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# ? May 3, 2024 06:34

mystes: May 31, 2006

Argh I pulled out this chromebook that I had installed linux on before, and went to reinstall linux, and I couldn't get the wifi to work. After all sorts of messing around with drivers and wasting a ton of time testing different bootable linux images and having nothing work, I finally remembered that this happened before a year ago when the clock wasn't set, so I manually set the time/date and then instantly the wifi started working again. I think I need to write "IF WIFI DOESN'T WORK SET CLOCK" in permanent marker on it or something.

# ? Oct 22, 2017 21:50

peepsalot: Apr 24, 2007; ��PEEP THIS...
��BITCH!

Is there a preferred way to accurately compare two strings representing version numbers from a shell script? ( #!/bin/sh -e )

# ? Oct 23, 2017 00:27

minato: Jun 7, 2004; cutty cain't hang, say 7-up.; Taco Defender

peepsalot posted:

Is there a preferred way to accurately compare two strings representing version numbers from a shell script? ( #!/bin/sh -e )

Stole this from Stack overflow. Basically, output the 2 versions, sort them using -V, compare the resulting top line to see which one is considered "first":

code:

function version_gt() {
  local version_a=$1
  local version_b=$2
  test "$(printf '%s\n%s' $version_a $version_b | sort -V | head -n 1)" != "$version_a";
}

# ? Oct 23, 2017 00:51

mystes: May 31, 2006

Does anyone know of any good introductory tutorials on the ip/iw commands for people who are used to ifconfig, route, etc.?

# ? Oct 24, 2017 03:09

minato: Jun 7, 2004; cutty cain't hang, say 7-up.; Taco Defender

This one has a pretty good mapping of old->new:
https://dougvitale.wordpress.com/2011/12/21/deprecated-linux-networking-commands-and-their-replacements/

# ? Oct 24, 2017 03:19

Furism: Feb 21, 2006; Live long and headbang

Is HTTP/2 available under nginx/CentOS now? Last time I checked only Ubuntu had it because it relied on some OpenSSL version.

# ? Oct 24, 2017 09:15

Plasmafountain: Jun 17, 2008

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Plasmafountain fucked around with this message at 23:56 on Feb 27, 2023

# ? Oct 25, 2017 22:23

RFC2324: Jun 7, 2012; http 418

Zero Gravitas posted:

Can anyone recommend a way to remote desktop to a fedora machine from a win 10 one? I used to be able to do this with an earlier version of fedora but now my new machine just gives tigervnc a black screen which is apparently a known issue that doesnt look like its going to get fixed anytime soon.

EDIT: This isnt urgent. Realised I asked this in this very thread seven months ago. I'll give that old stuff another go tomorrow night when its not 1am in the morning.

i seen to remember having to do some trick with ports last time i did this. phone posting tho so i can't find the link.

# ? Oct 25, 2017 22:41

hooah: Feb 6, 2006; WTF?

I'm using Ubuntu more on my laptop. It's got a dumb layout for the navigation keys: top to bottom it goes Home, End, PgUp, PgDn. I'd like to remap these so it goes Home, PgUp, PgDn, End. I've poked around some online and tried dconf Editor as well as editing /etc/default/keyboard to add "End:Prior,Prior:Next,Next:End" to XKBOPTIONS. So far neither option has worked. What might I be doing wrong?

# ? Oct 26, 2017 01:18

Truga: May 4, 2014; Lipstick Apathy

Hello, friend. Welcome to post-xmodmap hell, I hope you enjoy your stay. :rip:

You're probably going to have to modify some xkb files to get this to work consistently. And then modify them again every time there's an update to those files. I can check out how to do this easily tomorrow, since I have some scripts for similar stuff on my work laptop.

# ? Oct 26, 2017 01:28

Super-NintendoUser: Jan 16, 2004; COWABUNGERDER COMPADRES; Soiled Meat

I have a weird question about rhel6 connections per second.

So I run a service that uses xinetd, and the cps settings in there are pretty well defined. However I have a couple clients that don't allow xinetd, so the service is started up and backgrounded, then they use monit to keep it online.

That's all well and good but I've been seeing some errors from the service that are indicative of it bumping up against the connections per second setting. I spoke to the software vendor, and they told me to tune the xinetd parameter, but when I explained that we can't use it, they basically responded they don't know.

I figure there's some kind of kernel parameter that limits general network socket connections in a general way or per port outside of xinetd, but google is not giving me anything.

# ? Oct 26, 2017 19:14

Super-NintendoUser: Jan 16, 2004; COWABUNGERDER COMPADRES; Soiled Meat

Truga posted:

Hello, friend. Welcome to post-xmodmap hell, I hope you enjoy your stay.

You're probably going to have to modify some xkb files to get this to work consistently. And then modify them again every time there's an update to those files. I can check out how to do this easily tomorrow, since I have some scripts for similar stuff on my work laptop.

Just to follow up on this, when you solve this problem, make sure you document it, since you'll probably one day rebuild or upgrade that laptop and you don't want to deal with that nightmare again later.

# ? Oct 26, 2017 19:15

RFC2324: Jun 7, 2012; http 418

Jerk McJerkface posted:

I have a weird question about rhel6 connections per second.

So I run a service that uses xinetd, and the cps settings in there are pretty well defined. However I have a couple clients that don't allow xinetd, so the service is started up and backgrounded, then they use monit to keep it online.

That's all well and good but I've been seeing some errors from the service that are indicative of it bumping up against the connections per second setting. I spoke to the software vendor, and they told me to tune the xinetd parameter, but when I explained that we can't use it, they basically responded they don't know.

I figure there's some kind of kernel parameter that limits general network socket connections in a general way or per port outside of xinetd, but google is not giving me anything.

iirc you want to Google conntrack. not sure if the iptables conntrack is the same as the kernel conntrack i have dealt with before, but you are bumping into that.

# ? Oct 26, 2017 19:19

jre: Sep 2, 2011; To the cloud ?

Jerk McJerkface posted:

I have a weird question about rhel6 connections per second.

So I run a service that uses xinetd, and the cps settings in there are pretty well defined. However I have a couple clients that don't allow xinetd, so the service is started up and backgrounded, then they use monit to keep it online.

That's all well and good but I've been seeing some errors from the service that are indicative of it bumping up against the connections per second setting. I spoke to the software vendor, and they told me to tune the xinetd parameter, but when I explained that we can't use it, they basically responded they don't know.

I figure there's some kind of kernel parameter that limits general network socket connections in a general way or per port outside of xinetd, but google is not giving me anything.

You could be hitting the file descriptors limit. Do you know what user the process runs under and what the limits are set to?

# ? Oct 26, 2017 21:12

Furism: Feb 21, 2006; Live long and headbang

Furism posted:

Is HTTP/2 available under nginx/CentOS now? Last time I checked only Ubuntu had it because it relied on some OpenSSL version.

You guys are going to make me install a VM won't ya

# ? Oct 26, 2017 21:38

Super-NintendoUser: Jan 16, 2004; COWABUNGERDER COMPADRES; Soiled Meat

RFC2324 posted:

iirc you want to Google conntrack. not sure if the iptables conntrack is the same as the kernel conntrack i have dealt with before, but you are bumping into that.

The vendor followed up and said this is the setting that matters if you aren't using xinetd to maintain the service:

net.ipv4.tcp_max_syn_backlog = 4096

Have to look into that. It's a non-production issue, the client just saw some errors in the log and I have to provide an analysis, so I don't know how deep I have to go on fixing it.

# ? Oct 26, 2017 21:52

RFC2324: Jun 7, 2012; http 418

Jerk McJerkface posted:

The vendor followed up and said this is the setting that matters if you aren't using xinetd to maintain the service:

net.ipv4.tcp_max_syn_backlog = 4096

Have to look into that. It's a non-production issue, the client just saw some errors in the log and I have to provide an analysis, so I don't know how deep I have to go on fixing it.

Here is a copy of someones config with the same goal as you appear to have, but it has a few problems so make sure to sanity check.

https://gist.github.com/kfox/1942782

Good luck!

# ? Oct 26, 2017 21:57

nem: Jan 4, 2003; panel.dev
apnscp: cPanel evolved

Jerk McJerkface posted:

However I have a couple clients that don't allow xinetd, so the service is started up and backgrounded, then they use monit to keep it online.

Are you running the latest Monit, 5.24, or from EPEL, 5.14? Monit generated a ton of spurious connection issues to Apache and SpamAssassin that cleared up after upgrading to 5.24.

# ? Oct 26, 2017 22:01

thebigcow: Jan 3, 2001; Bully!

Furism posted:

You guys are going to make me install a VM won't ya

https://andreborud.com/how-to-setup-http2-on-centos-7-3/ This is two months old and says not out of the box.

# ? Oct 26, 2017 22:17

Super-NintendoUser: Jan 16, 2004; COWABUNGERDER COMPADRES; Soiled Meat

nem posted:

Are you running the latest Monit, 5.24, or from EPEL, 5.14? Monit generated a ton of spurious connection issues to Apache and SpamAssassin that cleared up after upgrading to 5.24.

Thanks for this, but I checked and this particular service isn't managed by monit, they have their own inhouse developed process monitoring service. That sounds bad, but this is a gigantic company that has a huge team of devs and this is not a problem.

# ? Oct 26, 2017 22:18

ToxicFrog: Apr 26, 2008

Zero Gravitas posted:

Can anyone recommend a way to remote desktop to a fedora machine from a win 10 one? I used to be able to do this with an earlier version of fedora but now my new machine just gives tigervnc a black screen which is apparently a known issue that doesnt look like its going to get fixed anytime soon.

EDIT: This isnt urgent. Realised I asked this in this very thread seven months ago. I'll give that old stuff another go tomorrow night when its not 1am in the morning.

After much faffing about with remote desktop some years ago, I eventually settled on installing X on the windows machine and using ssh -X. (Substitute NoMachine NX if you want persistence across sessions and/or don't want to install X separately.)

# ? Oct 26, 2017 22:23

Volguus: Mar 3, 2009

Zero Gravitas posted:

Can anyone recommend a way to remote desktop to a fedora machine from a win 10 one? I used to be able to do this with an earlier version of fedora but now my new machine just gives tigervnc a black screen which is apparently a known issue that doesnt look like its going to get fixed anytime soon.

EDIT: This isnt urgent. Realised I asked this in this very thread seven months ago. I'll give that old stuff another go tomorrow night when its not 1am in the morning.

I always installed cygwinX on a windows machine and it always worked perfectly. Normally I would use ssh -X (or ssh -Y) to login into the remote machine, then start whatever application I would need.

# ? Oct 26, 2017 23:39

RFC2324: Jun 7, 2012; http 418

Volguus posted:

I always installed cygwinX on a windows machine and it always worked perfectly. Normally I would use ssh -X (or ssh -Y) to login into the remote machine, then start whatever application I would need.

If you are going to do X forwarding, WSL with an xserv(xming is the goto) is much easier to deal with that cygwin.

# ? Oct 26, 2017 23:52

Volguus: Mar 3, 2009

RFC2324 posted:

If you are going to do X forwarding, WSL with an xserv(xming is the goto) is much easier to deal with that cygwin.

I guess to each his own.

Edit: Is this XMing that hasnt been updated since 2007? In 2008 I tried to use it and it wouldn't work on whatever windows version I had at the time. Clicking next in cygwin never seemed hard but hey ...

Volguus fucked around with this message at 02:29 on Oct 27, 2017

# ? Oct 27, 2017 02:23

mystes: May 31, 2006

I tried using Wayland and Sway, but it seemed pretty really buggy and I ended up switching back to i3 on X. I assume the issues were mostly with Sway rather than Wayland but I think I'm going to wait another year before I bother trying Wayland again.

# ? Oct 27, 2017 02:45

RFC2324: Jun 7, 2012; http 418

Volguus posted:

I guess to each his own.

Edit: Is this XMing that hasnt been updated since 2007? In 2008 I tried to use it and it wouldn't work on whatever windows version I had at the time. Clicking next in cygwin never seemed hard but hey ...

I've never had problems with xming, whether I used WSL or puTTY, but Cygwin has always been a nightmare for me to get running comparatively, and it has little quirks that make it behave different than a real Linux.

# ? Oct 27, 2017 03:04

Thermopyle: Jul 1, 2003; ...the stupid are cocksure while the intelligent are full of doubt. �Bertrand Russell

RFC2324 posted:

I've never had problems with xming, whether I used WSL or puTTY, but Cygwin has always been a nightmare for me to get running comparatively, and it has little quirks that make it behave different than a real Linux.

This is me in all respects. In fact, I just set up xming again this afternoon and it took about 2 minutes. Install it, turn on x11 forwarding in putty, done.

# ? Oct 27, 2017 03:27

Volguus: Mar 3, 2009

Thermopyle posted:

This is me in all respects. In fact, I just set up xming again this afternoon and it took about 2 minutes. Install it, turn on x11 forwarding in putty, done.

I setup cygwin (click next), run xinit, ssh -X host. Done.

# ? Oct 27, 2017 03:30

Tigren: Oct 3, 2003

mystes posted:

I tried using Wayland and Sway, but it seemed pretty really buggy and I ended up switching back to i3 on X. I assume the issues were mostly with Sway rather than Wayland but I think I'm going to wait another year before I bother trying Wayland again.

I have no idea what Sway is, but Fedora has been shipping Wayland as the standard for about a year now and I believe Ubuntu made it the default in their own newest 17.10 release. It's definitely ready for production.

# ? Oct 27, 2017 03:40

Thermopyle: Jul 1, 2003; ...the stupid are cocksure while the intelligent are full of doubt. �Bertrand Russell

Volguus posted:

I setup cygwin (click next), run xinit, ssh -X host. Done.

To be clear, I don't have any problem with cygwin for doing what you're describing here.

# ? Oct 27, 2017 03:42

RFC2324: Jun 7, 2012; http 418

Thermopyle posted:

To be clear, I don't have any problem with cygwin for doing what you're describing here.

Its been years since I bothered with cygwin, but just xinit never worked right for me without having to gently caress with configs for a couple hours, and even then performance was crap. Last time I touched it was 2005(?) so maybe the stock install is less complete poo poo now.

# ? Oct 27, 2017 03:50

Volguus: Mar 3, 2009

RFC2324 posted:

Its been years since I bothered with cygwin, but just xinit never worked right for me without having to gently caress with configs for a couple hours, and even then performance was crap. Last time I touched it was 2005(?) so maybe the stock install is less complete poo poo now.

Haha. Here i come with xming experience from 2008 (shitshow, didn't work, maybe the paid version is better) and you with cygwin from 2005. Both cases are from 10 and 15 years ago, I woudl think that's safe to assume they don't match anymore (except xming, since the free version is still from 2007).

When I'm on windows and need that X server I always install cygwin.Last time i did that was 3 months ago on a windows 10 machine. Like always, worked without a hitch. Should it stop working ... yes, definitely I would try something else, especially now with windows 10 having that linux-on-windows system. But until then ... meh, it does what I need it to do.

Tigren posted:

I have no idea what Sway is, but Fedora has been shipping Wayland as the standard for about a year now and I believe Ubuntu made it the default in their own newest 17.10 release. It's definitely ready for production.

Sway is a window manager for wayland, similar to i3 (i3 is for X11). The only videocards that have trouble with wayland (as far as I know) are nvidia with the proprietary driver. Nouveau maybe works (I have a 970 so nouveau doesn't work on that), but the nvidia proprietary driver doesn't.
Just the other day I tried gnome-wayland in F27. While, to much of my surprise, it started and it showed me the desktop, it was unusable since gnome-shell was eating 1500% CPU. Weston by itself didn't start. Now, it could be F27-beta bugs, but ... yea, I will try it again maybe next year.

# ? Oct 27, 2017 04:32

Furism: Feb 21, 2006; Live long and headbang

thebigcow posted:

https://andreborud.com/how-to-setup-http2-on-centos-7-3/ This is two months old and says not out of the box.

Perfect, thanks a lot! OpenSSL 1.0.2 it is.

# ? Oct 27, 2017 08:43

xzzy: Mar 5, 2009

WSL is really cool though. It's almost like running a VM because you update it and add packages like a normal Ubuntu system, but it's not actually a VM. :science:

# ? Oct 27, 2017 13:08

Furism: Feb 21, 2006; Live long and headbang

xzzy posted:

WSL is really cool though. It's almost like running a VM because you update it and add packages like a normal Ubuntu system, but it's not actually a VM.

I use it to run nginx for development on Windows and it's actually better than the native nginx win32 binaries. I was pleasantly surprised to see they got even the networking and sockets right.

# ? Oct 27, 2017 13:49

feedmegin: Jul 30, 2008

Furism posted:

I use it to run nginx for development on Windows and it's actually better than the native nginx win32 binaries. I was pleasantly surprised to see they got even the networking and sockets right.

Doing it right down in the Windows kernel rather than via userspace like Wine is way better for efficiency. I wonder if they had to make kernel changes to handle stuff like fork() properly...

# ? Oct 27, 2017 13:52

Boris Galerkin: Dec 17, 2011; I don't understand why I can't harass people online. Seriously, somebody please explain why I shouldn't be allowed to stalk others on social media!

There�s some info on it on this blog.

quote:

The Windows NT kernel was designed from the beginning to support running POSIX, OS/2, and other subsystems. In the early days, these were just user-mode programs that would interact with ntdll to perform system calls. Since the Windows NT kernel supported POSIX there was already a fork system call implemented in the kernel. However, the Windows NT call for fork, NtCreateProcess, is not directly compatible with the Linux syscall so it has some special handling you can read about more under System Calls.

And

quote:

The WSL kernel drivers, lxss.sys and lxcore.sys, handle the Linux system call requests and translate them to the Windows NT kernel. None of this code came from the Linux kernel, it was all re-implemented by Windows engineers. This is truly mind blowing.

When a syscall is made from a Linux executable it gets passed to lxcore.sys which will translate it into the equivalent Windows NT call. For example, open to NtOpenFile and kill to NTTerminateProcess. If there is no mapping then the Windows kernel mode driver will handle the request directly. This was the case for fork, which has lxcore.sys prepare the process to be copied and then call the appropriate Windows NT kernel APIs to create and copy the process.

# ? Oct 27, 2017 14:51

Double Punctuation: Dec 30, 2009; Ships were made for sinking;
Whiskey made for drinking;
If we were made of cellophane
We'd all get stinking drunk much faster!

I have been wondering if you could do a syscall to lxss.sys from Win32 or NT native code to get fork working well for Cygwin and MinGW. They would never support it officially due to it being undocumented, but it would probably work better than NtCreateProcess or making your own hacky kernel service. What calling convention does it use?

# ? Oct 27, 2017 19:46

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# ? May 3, 2024 06:34

hooah: Feb 6, 2006; WTF?

Truga posted:

Hello, friend. Welcome to post-xmodmap hell, I hope you enjoy your stay.

You're probably going to have to modify some xkb files to get this to work consistently. And then modify them again every time there's an update to those files. I can check out how to do this easily tomorrow, since I have some scripts for similar stuff on my work laptop.

Did you have time to look into this?

# ? Oct 28, 2017 01:21

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

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