@Braiam Thanks. So the wifi signal won't be shown?

Input:

Little Sue went
out to play, and
found herself a log.
The log was
heavy.

command:

$ perl -00pe 's/\n(?=[a-z])/ /g' file
Little Sue went out to play, and found herself a log.
The log was heavy.

works perfectly. Is there any alternate efficient perl method?

I think the above perl command will load the whole paragraph into memory.

Above perl command will replace all the newline characters by spaces only if it's followed by an lowercase letter.

@terdon ^^^

@fonix232 hi. So, what exactly do you need?

What is special about its being a school?

hi Terdon. The specialty needs are, well - ease of use for students AND teachers, possibility to control internet access (via squidguard or other means) to specific computers or groups of computers, etc. - basically an SMB (Small-Medium Business) solution, dumbed down to a great extent

That's what I don't get. Why does it need to be dumbed down? How many people need to be able to administer it?

Just use a normal one and do the admin stuff yourself. Why do more people need to be able to?

In any case, did you check out webmin? That's a web-based admin interface that lets you configure anything you like.

I know webmin, I use it for remote administration, and for my own server too :)

It needs to be dumbed down because most of the IT teachers are actually quite dumb when it comes to IT... they know the basics (MS Office, Internet, HTML and CSS basics, and e-mail), but if I give them a complex interface like Webmin they'll say roll the whole system back

@fonix232 Ah, and do they all need to be administrators? Why not keep root access for yourself alone?

Right now the whole block-internet-to-students-in-Room-X is about 5-6 clicks - launch web interface, select User and Group Management, select Rooms, select the specific Room (which is a simple group of devices), and set network access level to internal-only

@terdon I will be the only root, but some management will be needed for them too which is easy

I see.

Can't webmin do this? It should be possible to set up different access levels for it.

yes, but Webmin, to the extent of my knowledge, has no support for grouping devices and managing their internet access

No but that is presumably done by Linux anyway. I'm thinking that once you set up the necessary groups, then you can control them via webmin.

I have no idea how you group devices though.

How is this set up? The student's PCs act as terminals and connect to a single centralized server?

I think the current solution is NIS-based

All PCs are Windows clients joined to the domain

Ah!

but control of network access I think is user based

all users who are logged in on the specific devices, restrict network access

So the Windows machine connects to the Linux server which then provides access to the internet.

well... not exactly, not at the moment

due to limited funding we have limited networking equipment

most of the switches are 100Mb only, we have ONE switch that supports Gigabit, the central one

so basically we have set up switches in each room to provide internet connection

I don't really know enough about this kind of thing to help I'm afraid. We need some of our resident sysadmins. @slm @derobert @Caleb @JennyD or anyone else?

The people I pinged are all experienced sysadmins, maybe one of them has time to help out.

In the meantime @fonix232 do include this information in your question. You need to explain precisely what you need in order to get a good answer. I would also change the focus to ask for a way to achieve this setup rather than a ready-made solution.

I'm working on it, @terdon, but the list is quite long :P

Yeah, I can imagine. No way around it though :(

@Anthon Whenever you get in chat: comment acknowledged, you can remove it if you want ;) I'll improve the contents I submit for tags, thanks.

@JohnWHSmith ah, good, I wanted to talk to you about that :)

Did Anthon just tell you not to explain what the tag describes in the tag excerpt but instead to explain when the tag should be used?

anyone knows if there's something wrong here? askubuntu.com/a/527136/169736

@Braiam Ubuntu doesn't cater to a culture that wants to know why things are the way they are?

@Caleb beats me...

@Braiam Ubuntu users want simple solutions for their problems, not the explanation for the workings of it :P

@Caleb any chance you have a free minute?

It was just a single downvote. Why look for reasons?

@fonix232 did you see my last message? Some of the ones on that list look worth checking out.

@terdon, no I see no list coming from you

I can't give you a list, you need to run the search.

Umm, hang on, I could have sworn I'd left you a comment.

:)

I believe you did not

or at least it is not showing up

Yes I did:

ah okay

For example:

I thought here

> Skolelinux is the Debian-edu project's Custom Debian Distribution (CDD) in development. It is aiming to provide an out-of-the-box localised environment tailored for schools and universities. The out-of-the-box environment comes with 75 applications aimed at schools, as well as 15 network services pre-configured for a school environment. The simple, three-question installation requires minimal technical knowledge. Skolelinux is Debian, which means, among other things,

> that there are no license costs or worries, and that upgrade and maintenance of the software can be done over the Internet with the power of Debian's apt-get. The core goals of Skolelinux are localisation and ease of system administration.

yes I've seen the distrowatch list of edu distros, but it's quite scarce

Yeah...

tried Skolelinux already, see the question ;)

Ah, bugger. Sorry.

the thing is, Skolelinux is very rigid

Yeah, I just re-read your Q.

it uses GOSA2 for frontend which is nice, but quite hard on the newcomers

for the user control part

Sulix would be cool but... lots of problems

Have you looked at edubuntu?

and since the company centralized the management of SuliXerver, it gets kinda hard to manage rights...

like, a week ago it took them 3 days to fix a read permission for one of our teachers

she couldn't access her own folder and we couldn't do anything from server side, most commands are restricted

yes I did, I might give it a go later

@fonix232 No, that's just ridiculous. You need full access to your own effin machine!

past selves of all of us are my best friends when googling 8-)

@JohnWHSmith Thanks. The problem is that I can review your suggested edits, but all < 20K users (like me) only can reject or accept tag edits, not improve by editing them myself (my tag edits are reviewed as well until I reach 20K).

@slm I have never taken a selfie, and I still look as good as in any past photo of me that you might find (I still remember some exchange about captain Picard).

That was me I think :)

@Anthon picard is your doppleganger

You have to admit, those two pictures looked very similar.

the three laptops and the keyboard?

or wait those are monitors my bad

@fonix232 Wow, well spotted. But no, we're talking about his old profile pick.

ah okay :P and I seriously need to get off of my laptop now, I've read "profile dick" first

oh and yes it is indeed ridiculous

@fonix232 There are other pictures out there on which I feature. And that is indeed my monitor setup (2 landscape, one portrait), I had to change because I got harassed as a Patrick Stewart look-al-like

seriously, I wanted to add a device that has no screen to the DHCP system to have fixed IP

nope, can't do that

@Anthon can I see that picture?

@fonix232 I had a look at your question, but I'm sorry I don't have any good suggestions. I'm a sysadmin at big companies, so I don't have much experience with the kind of setup you need.

@JennyD basically, same as an SMB, BUT, with a dumbed down interface for students and teachers to use - we're talking about a high school

@fonix232 Click on the "Nov 29 '13 at 14:06" of the message I pasted above, you'll see the comparison.

@fonix232 yeah, it's the dumbed-down interface I have no experience with :-)

ah, okay, thanks any way Jenny

and indeed the similarity is smashing

It must be the earl-grey tea and the Alessi teapot

@Anthon Wow, that's really you?

@fonix232 I'm going to ping a couple of people about it though, I've a fair number of sysadmin friends who amazingly don't hang out here :-)

that's... actually quite surprising

@JennyD would his Q be on topic on SF?

and no, not the fact that you have friends, but that they don't come to Stack Exchange

@terdon I think it is more Linux-oriented at the moment

@terdon Unfortunately not, it would be closed for "too broad" or "software rec", neither of which is on-topic

Hi guys. People around on a Saturday? How strange.

okay, different question

@fonix232 not everyone enjoys solving other people's problems :-)

is there a software that can change squidguard's settings to not to let given users through based on the computers they're logged in from?

say we have a room set up with computers 1-14, and students A-N sitting at them

@terdon Yes I did, but in a comment on a Answer by John. Pointed to blog.stackoverflow.com/2011/03/redesigned-tags-page as well.

software checks each computer for the current students logged in, and restricts access via squidguard to the internet

@Anthon Thanks, I found the comment.

It is kind of nasty that with < 20K you cannot make improvements, as my own tag edits need reviewing.

@Anthon I know, you need to get more rep! We need you to have free rein.

okay I gotta reboot now

testing some stuff

brb

@JennyD Well, they could ask their own questions. :-)

hi @JennyD

hi @terdon

Hi

@fonix232 I mentioned your question in the ServerFault chat room, just in case someone there has any idea - usually that kind of question gets a better response when it comes from someone familiar than from someone they've never seen before :-)

@FaheemMitha hi yourself, and everyone else :-)

darnit

why can't Debian Edu come with some lightweight desktop, say, XFCE?

or Openbox

Apparently we have a visitor. hi @fonix232.

hey Faheem

I've been here for a while :)

@fonix232 Do you want to configure it based only on computer or on the combination computer+user?

@fonix232 did you post a question? i'm unclear what you asked, if anything

Jenny D, it's quite complex actually... the current system, SuliXerver (don't know if you're familiar with it) can assign devices to a 'room' (a group of devices), then that room's internet access can be managed (sans the teacher's computer). But what it does basically is to find the computers in the group, find the users logged in the computers, and restrict their access via the proxy

@fonix232 did you check the doc at squidguard.org/Doc/sourceacl.html ? Seems it should be able to do what you want

Jenny, yes if I have a fix group

say, in a company

but in a school, the student accounts in a room change ever 45 minutes

I'll have a run-in with Karoshi Server now

@fonix232 So you want it to change based on the user, not based on which computer they're on.

Jenny D, no, I want to change it based on which computer they're on

IF(student.isOnRestrictedComputer) { disableInternetAccess() }

so say, after the end of the lecture, if they log in to the wifi of the school, they can use that

even if the teacher forgot to raise the restriction

@terdon I see. Interesting. Wow, someone with an actual sensible question.

It happens every now and then.

ah, so during class times all students should be unable to bypass restrictions, but after class they should be able to, without changing computers?

I thought Debian has extensive support for modification.

not exactly

let me explain it in detail

@fonix232 have you talked to the Debian edu people directly?

Not yet, Faheem, but Debian Edu at the moment is way too strict on its internal structure

the ports, naming convention, LDAP schemes, etc.

I think I will make a customized branch of it

but this restriction business is the hardest part

it could be solved with a bash script, yea

@IonicăBizău what country is this?

I'm guessing somewhere in Europe.

I'd say Romania

yeah, it's definitely not something I've any experience with - I've only done sysadmin in large businesses, they pay for expensive stuff to do that kind of thing :-)

but it's a very interesting question and I really wish I had a good answer

@JennyD yea, so far we've been paying monthly 250$ for this shitty system ;)

I'd talk to Debian, if only to find out if you have parallel efforts going on elsewhere in your country.Is localization a big issue?

but the maintainer of the school is, well, not exactly famous about liking expenses

@IonicăBizău disclaimer - I'm a Debian user. Everyone else here knows that already, but I thought I'd mention it.

if I was to tell them we can cut expenses, they'd stop me there, congratulate me, and take the money :D

@FaheemMitha I prefer FreeBSD but I can't think of any solution there to this problem :-)

Faheem, there is no parallel effort going on, I know this for a fact. Our government actually recommends this SuliXerver sh*t to be ran, and most schools do because while it sucks, it's easier to manage

@fonix232 Don't tell them that. Setting it up will cost money too. Are you planning to do it singlehanded? Don't, you'll go nuts.

localization is no issue, most of the stuff is available in Hungarian

@fonix232 Sheesh, that sucks.

only need to get a translation for GOSA2

I'd still start talking to Debian.

Faheem, can't can't tell, they get the payment receipts directly, and they pay it

if it's missing, they ask where it's gone

why it didn't come

etc.

Does gentoo have an educational version? They're the largest source based distribution.

Faheem, I'd be more comfortable with Debian

mostly used that, and some small part-time SUSE/RHEC

and yes I plan to do it alone, well, with the other sysadmin

@fonix232 Ok. In any case, there doesn't seem to be anything for Gentoo.

yup

well, I've spammed the link to the question a bit, hope someone shows up with some good suggestion

otherwise it seems like a new market for someone else to build a solution :-)

@fonix232 maybe be more specific about what is missing for your Debian solution.

@JennyD I think if someone built that, they could get quite a sum from a few high schools for deployment+support

In the question, I mean. Ok, off to dinner. bbl.

@fonix232 Sounds like a business opportunity. Talk to the local Debian community, perhaps?

Haha, might do that :D

okay, gotta restart now

I'm going to go do some adult stuff. Laundry or something.

back

okay, now I kinda hate Win10...

@fonix232 i'm sure debian edu has an irc channel. go there, post that question link. if you wait, probably someone will talk to you. North America is waking up now.

Actually, 11 am on the East Coast, already.

@fonix232 Windows is very hateable.

I now have enough rep on Unix and Linux that it has made it into my top 5 sites :D

@Seth Congrats.

hehe, thanks. It's not a big deal, but still fun ;)

@Seth Yay! Welcome aboard :)

thank you :)

@Ramesh @Gnouc May I ask why you guys voted not to re-open unix.stackexchange.com/q/159252/4358?

@Patrick, reopened.

I mean voted to reopen.

ty

@Patrick: I think it's duplicated

@Gnouc how? the other question is asking about duplicate IPs. this one is asking about duplicate MAC addrs.

And yes, sometimes disimilar questions have the same answer, but in this case, the answers aren't the same either.

@Patrick: I think the last answer and its comment explain that question well enough.

@Anthon it's freaky how much you guys look alike.

@Patrick @Gnouc - I originally closed that Q as a dup when I looked at it. I've reopened it since it looked like 3 others agreed w/ Patrick, I only VtC solo on it. In looking at the other A to the marked dup I still think that that was the reason but if someone wants to expand in more technical terms on this Q go for it. I felt that there was enough explanation on the A + comments as @gnouc though.

@slm, thanks for this. It helped me in setting up kvm on a laptop machine.

@Ramesh - your welcome!

I just installed a base fedora package in my kvm.

WTF?

I did a network installation. So does network installation doesn't have yum ?

@terdon DV

@Ramesh it should

@slm well, now after reboot the virtual machine doesn't show up. It says no bootable device.

@Ramesh - ???

@slm, I was trying to setup kvm. I was able to configure the bridged network in a wireless interface.

I did a network installation of fedora using the virt-manager. Now, after reboot, when I start the virtual machine, it gives me the error "No bootable device".

I've typically used virt-manager to do my guest setups, I've done them from cli too, but virt-manager takes all the switch busy out of my way which can be annoying with kvm

@Patrick - +1 nice A as usual 8-)

@slm so is it possible that the reboot had made the installation unavailable?

Yes, and hey @Patrick I'd missed that you'd made 20k, well done!

ty :-)

@Ramesh - no idea. KVM has generally just worked for me.

yeah another 20ker

@Patrick: Good job!

BTW (a bit of a public service announcement) - if you have things that you deal with on a day to day basis please consider writing them up as Q's or Q&A. We're in a bit of a dry spell for good Q's.

Seems we have many A'ers and not enough Q's (IMO) not sure what other's thoughts are on this.

BLOG!

I'm too busy learning about bundler and sinatra to write a blog article 8-)

@FaheemMitha I'm from Romania, Europe. What's the context?

@Patrick - or is that directed to others?

@slm I just wrote this yesterday.

@IonicăBizău Context?

@FaheemMitha I don't understand what you mean.

@slm to anyone

I'm hyper-sensitive to the blog now, apparently 8-)

@FaheemMitha Yes, I'm talking about this message.

@FaheemMitha he's answering you. I think you pinged him by accident:

@FaheemMitha And about this one.

@IonicăBizău Ah, right. Yes, it was an accident. I meant to ask @fonix232

true if you find a lack of Q's here we do have a blog that strugee is in charge of, we're always looking for content and don't expect the usuals to do most things, many of your 20k+ rep'd users are more than capable.

i suck at the tab completion thing.

Sorry about that.

@terdon But then somebody said I'd say Romania.

No problem, just wanted to clarify the thing. :smile:

Presumably because they thought Faheem was asking you.

@terdon Right. Confusion all around.

@Ramesh ah, I missed you answered it. I saw your Q, thanks, nice job!

@slm, that's why I was thanking you for your answer. It helped me check the blog that you had given in your answer.

Now I believe I am having this problem. But my xml file seems correct.

BTW if you're interested in writing a blog post we have many good ideas in this meta post: meta.unix.stackexchange.com/questions/743/…

I would consider this a good way to take something you're interested in and breaking it down for others, it doesn't have to be something that you're an expert on. Doing this is a good way to generate new sources of Q's that you can then either self A or pose to everyone else here too!

Sure. I will try and do it. But will there be reach for blog?

@Ramesh - how do you mean? Will ppl see it?

I mean, how many people will really look into blog? For me, if I see some answer in SE, it is a good source and 90% of the time the answer works.

Blog content, BTW, is extremely valuable as a reference resource, so it can be woven into the site on existing A's as such, so it get's more of a "long tail" type of exposure that way.

oh ok. I will try and move some of my self answered questions to the blog.

@Ramesh people will read a blog post. many more than will read an individual question/answer, probably.

KVM & docker are very rich areas that are under represented currently on the internet. They're extremely fragmented and disjoint.

but it should be of somewhat general interest, imo

I post it here mainly because I hope some experts will actually evaluate the answer and tell me if am wrong :)

of course don't do it if it feels like work. It should be something on your horizon that you've been meaning to delve into

we have not been getting lots of good questions of late :(

blog articles can be a group effort too. I've wanted to for years write up a good article on active directory + linux. This is a horrible mess when I've looked into in the past.

@slm What! Don't encourage the plebes to slack off! Work, you ♦-less slaves!

@Ramesh no they've been lack luster

lol

Sorry, lost my self-control there for a second :)

we get $0.0000001 per A given now that we're mods, I'm going to buy a pack of gum w/ mine.

Shhhh, dude, that's a secret!

@terdon - did you get your mod business cards?

@terdon, drunk with mod power now :)

@slm Heh, no.

@Ramesh hic!

here I'll post a image of mine

Sorry, not hic, not hick.

@slm You got some? Cool, do post.

@Ramesh that was actually a question of mine, at the time of elections. regrettably, i never posted it.

What should be the storage format for kvm?

@Patrick Ouch. I did not laugh. Honest!

:)

@Patrick ouch

@terdon I don't mind. It is funny. It's a result of my own stupidity :-)

All the mistakes I've made have been the result of my own stupidity.

The laptop is actually still running. Havent rebooted it yet. Going to see if I can rebuild it without the use of a LiveCD, just for the challenge

It's like changing a car tire while driving down the highway doing 80

exactly!

well, chuck norris can do it :)

...and this guy: i.imgur.com/cD8Y7fh.gif

We took our kids to the grocery store last night which also has a dining area and the tv's there were showing Walker, Texas Ranger. What a high quality show that was....

@Patrick that's fake

that guy is dead if the car goes down

Ok, then, how about this guy:

that seems more real

Why would the first be fake? just because it's stupid doesn't mean its fake

how do you get the lug nuts off....

seems less possible

it's obviously real enough, but still

Well, I didn't say it's not staged. They could have already pre-loosened them

those tires seem awfully light too

have you ever tried to pick up a tire, they're heavy

Well, time to post a question for kvm thingy.

@slm doughnuts (spare tires) are really small and light

yeah I thought of those, but that looks like a regular tire. I guess it's real,

I just watched the mythbusters where they showed how to drive the car like that

it was pretty funny, jaimie slammed his head pretty good on one of the attempts though

they finally had a stunt driver come on and show them how to do it

Well, it has been reported by a "real" newspaper, though not a particularly good one AFAIK, and they cite a saudi paper as well: nydailynews.com/autos/…

that guy could drive the car all over the place, it was crazy

the saudi's are crazy w/ the crap they do while driving.

We worry about texting...and you've got this going on

@slm I doubt they do it in a regular basis :)

yeah it's not during work rush hour or anything

@terdon I wonder how many cars they trashed practicing that

but still, everytime I watch these videos I'm blown away

@Patrick - I had that exact same thought

only took me 30 cars till I got it right

Well, when you're sitting on land chock full of oil, you've probably got lots of money to throw away

there there's the fails compilcations

@slm Noooooo! Those are worse than TVTropes links.

I think I'm channeling kwiwy today

what happened to kiwy?

@slm is that really 20 min of people falling down?

@slm virtualization is a good area to document.

@FaheemMitha he got a new job and has been busy. He was here the other day and put a Q up + a bounty on it.

apparently it's 20 min..

Question. I have a VPS which was just shut down because of too much load. The service wrote:

They did. Anyway, what is a good way of logging of CPU/Memory for a VPS like that?

This just happened - they were very unspecific. I don't really use that machine except for backups. I did put quite a lot of files on it the other day - it has an apache server. maybe it's been getting downloads.

Is this a reasonable question to ask about on the web site?

I think there already are a few about measuring CPU/Mem usage.

Didn't @slm post a nice Q&A on that?

Well, this needs to be unmonitored and logged.

@terdon Maybe.

@FaheemMitha this looks like what you're after:

munin-monitoring.org

@terdon Hmm, looks good

I'd written a couple of simple scripts.

@terdon scripts?

One logged the max memory used by a process or program name:

#!/usr/bin/perl -w
use strict;
use Number::Bytes::Human qw(format_bytes);
use v5.10;
use Math::Round;
my $max_mem=0;
my %MAX;
my $name=$ARGV[0];
## If we have given a process name to monitor
while (1){
    my @pids;
    if ($name=~/^\d+$/) {
	$pids[0]=$name
    }
    else {
	@pids=split(/\n/,`pgrep $name`);
    }
    my $running=$#pids;
    exit(0) unless $pids[0];
    foreach my $pid (@pids) {
	my $is_running=`ps aux | grep -v grep | grep -wc $pid `;
	chomp($is_running);
	unless ($is_running){

@terdon This is separate from munin?

Yeah, just a little script I wrote.

Huh, and the same thing more or less in bash apparently:

#!/bin/bash

mem=0;
## If we have given a process name to monitor
while [ 1 ]; do
    pid=`pgrep $1`
    size=$(ps  -o size  -p "$pid" --no-headers);
    bytes=$((1024*1024*1024))
    gigs=$(($size/$bytes))
    echo "$size $bytes $gigs"
    exit
    if [[ $aa > 0 ]]
    then
    size=`top -cbd .10 -n 1 | grep -w $1 | grep -v grep | gawk '(\$NF=="$1"){print \$7}' | perl -ne 's/(\d+)\w+/\$1/; print;'`
	echo "YES $size top -cbd .10 -n 1 | grep -w $1 | grep -v grep | gawk '(\$NF=="$1"){print \$7}' | perl -ne 's/(\d+)\w+/\$1/; print;'"

Does anyone know the http URL for Ubuntu archive for network installation?

This one seems not to work.

@Ramesh Wrong chat room:

They'll know.

@terdon actually, the think i really need here is something to send me an email when something abnormal has occurred. or better still, self-regulate it, because i may not always be around to intervene.

@FaheemMitha Well, take one of those scripts, the bash one for example, and make it exit with a bad exit code when something exceeds a threshold. Then, run the script with foo.sh || mail ... to send you an email.

Hmm, no, the bash one is buggy. I don't seem to set $f anywhere.

@terdon That's one way to go. Is that something you've used? It's weird - the service has a graph. But network usage is igsignificant, and if it isn't network associated, what could it be? i'm not doing anything on that machine. I'm just doing backups and running an apache server.

Well, if you are compressing the backups, that could explain it.

@terdon I'm not. Just straight rsync. Is rsync very CPU intensive, perhaps?

and the backups are only of email. i don't really get that much email.

@FaheemMitha Might be if it has to compare a lot of files to see whether or not to copy them. This is pure speculation mind you.

@terdon hmm. i think the rsync running serverside does take comparatively large resources.

@slm Skeptics!

@FaheemMitha here, this should email you if either your CPU usage or MEM usage exceeds 20%:

#!/usr/bin/env bash
max=20;
while :
do
    mem=$(ps ax -o pid=,%mem= | sort -rnk2 | head -n1)
    cpu=$(ps ax -o pid=,%cpu= | sort -rnk2 | head -n1)

    perl -le 'exit(1) if $ARGV[0] > $ARGV[1]' ${cpu## [0-9]* } $max ||
      echo "Max cpu exceeded. Cpu: $cpu" | mail [email protected] && exit;
    perl -le 'exit(1) if $ARGV[0] > $ARGV[1]' ${mem## [0-9]* } $max ||
      echo "Max memory exceeded: $mem" | mail [email protected] && exit;
      sleep 1;
done

@terdon that looks economical. have you tested/used it?

Very briefly, only just now.

I am not at all sure about the mail format, I've never used that.

The rest of it should work though.

Currently experiencing bugs.debian.org/696981

sigh.

Munin has alerts.

According to the graphs they supplied i had load everages spiking at 15 or thereabouts today. that's very weird.

someone suggested atop

atop actually looks pretty good. it does logging by default.