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How to get a script to ask for ssh login password only once?
by Chris Green 05 Feb '18

05 Feb '18

I have a script that runs ssh several times to do some manipulations on a remote system and also runs rsync to the same remote system two or three times. Is there some way to get a single entry of the ssh password to work for all the ssh and rsync calls? I *could* use key authentication but that has some downsides so I'd prefer to remain with using a password. One approach is to use 'ControlMaster auto' in the .ssh/config which means all subsequent logins will re-use the first one, this however means that I need to have a 'persistent' first ssh. I've managed this by doing 'ssh -fN esprimo bash' at the start of the script but this then leaves the ssh running for ever and I'd prefer that not to happen. Has anyone got any better ideas? -- Chris Green

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2600 meeting at 18:00 on Friday the 2nd February.
by Viperfang 30 Jan '18

30 Jan '18

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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New Server Installation Traditional BIOS mode or EUFI mode?
by steve-ALUG＠hst.me.uk 29 Jan '18

29 Jan '18

Having brought myself a shiny new Lenovo Thinkserver https://www.serversdirect.co.uk/p/1182461/lenovo-thinkserver-ts150-intel-pe… and tracked down all the cables and caddies required to make it run... I started installing *buntu on it, and then I had a thought, stopped and now not sure of the best way to go. It can run in EUFI mode, or traditional BIOS mode. Any thoughts? I've never had a machine with EUFI. Is that the way to go? Any gotchas? Any thoughts or experience appreciated. Cheers Steve

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autoreply to email for non-existent users - (resent because I sent the previous one from the wrong email address!)
by mick 29 Jan '18

29 Jan '18

(Apologies to list maintainers. I'm an idiot. Please delete the earlier mail sent from the wrong address). Hi Guys Some advice please. I own a bunch of domains, not all of which have many (or in some cases, any) real users. One domain name in particular is (accidentally) very similar to a domain in use by a UK QUANGO (one character different). Consequently my domain receives a fair amount of email intended for the other. Naturally I just bounce all email to my domain with a "550 5.1.1 <blah@domain>: Recipient address rejected: User unknown in virtual mailbox table;" When I first set up mail on the domain (back in 2011) and started to get lots of mail I did some research and found the QUANGO which should be getting the email. I contacted them and told them about the issue and suggested that they let all their contacts know about the problem. Herein, of course, lies a difficulty. Apart from their regular correspondents, they cannot know in advance who will email them. I left it, and figured that over time the volume of email would tail off as people caught on. But now, seven years later, I'm /still/ getting mail to my domain which should go elsewhere and which I simply bounce. My logs get cluttered with the bounce message and the end user may or may not know what to do about the failed delivery since I'm just telling them that the user doesn't exist, when they may think he does. Now to the question. I'm building a new email server (postfix) and I'm moving some of my doamins to that new server. Since it's a nice clean sparkly new server I'd like to ensure that I don't just move an existing problem from one MTA to another. So I've been pondering whether (and if so how) to implement an autoreply mechanism for my domain which sends a friendly message to the sender saying something like "Hi, you may have a typo in your email address for blah@mydomain. I run that domain and I get a lot of email there which is probably intended for blah@otherdomain. You may like to try resending to the proper address." I think I could probably set up something using vacation with a catchall alias for any address at my domain. But I'm aware of the potential for a complete balls up if I get this wrong. If "bad people" (TM) find that my mail system will autorespond to any address at a particular domain it could be used as a spamming mechanism which might get my sparkly new MTA blacklisted. I don't want that. So - any advice on the best approach? Or should I just suck it up as I currently do and not bother trying to be helpful? Cheers Mick --------------------------------------------------------------------- Mick Morgan gpg fingerprint: FC23 3338 F664 5E66 876B 72C0 0A1F E60B 5BAD D312 http://baldric.net/about-trivia ---------------------------------------------------------------------

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RAID: mdadm vs brtfs raid
by steve-ALUG＠hst.me.uk 28 Jan '18

28 Jan '18

I was reading the latest Linux Format which is talking about building a new machine. It really surprised me when talking about RAID when it suggested to use btrfs instead of mdadm. Even if I use mdadm, I may try out btfs instead of ext4. I was wondering if anyone had any thoughts? Steve

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Combining log files
by Mark Rogers 26 Jan '18

26 Jan '18

I have many gigabytes of .gz compressed log files, generally in very small files. For example, one file only contains entries from 20180114-205608 to 20180114-205746 (about 90s), and is about 350k compressed. I want to extract these and combine them into one file per day*, compressed. Log file entries are in date/time order, and filenames are easily sorted into date/time order too, so I can easily generate a stream of log entries in date/time order from which to work. So I assume that what I need is something to pipe that to that will look at the date of each line, and if it's changed close any existing output file, open a new one (gzipped), and write to it until the date changes or EOF. I could write something like that in a scripting language (for my sins PHP would be easiest, Python I'm getting better at, bash could likely do it too). But given the volume of data are there any suggestions as to the "right" tool to use? Is this a job for awk or similar? As an aside: The files are all archived on my Linux box, but they're sourced from a Windows box, so a cross-platform solution would allow me to do it on the host; transferring lots of small files isn't as efficient as a few big files (athough I have archives going back years on my Linux box to work through first). * I say a file per day but ideally I could be flexible about the period - day is most likely and probably easiest though -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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Network monitoring scripts
by Mark Rogers 22 Jan '18

22 Jan '18

I have a Pi which is set up with a read-only filesystem, and as such packaged network monitoring solutions aren't happy. Neither wicd nor network-manager like this setup. I'm not a fan of either, to be honest - for a GUI based PC they have benefits but for a headless box something simpler will suffice. I have cobbled together a basic bash script that checks to see if it can ping the default gateway and restarts wifi otherwise, but its far from elegant. Has anyone done anything similar or found any similar scripts online that they use? Ideally, for example, it would be able to "manage" both eth0 and wlan0 (or even wlan1 - in the case of a Pi 3 with an external Wifi added in for better signal strength). (I'm worried about edge cases with my current script. I can either run in through cron, but that risks it thinking the network is offline just because it hasn't come up yet after a boot which might have bad side effects. I'm currently running it as a systemd service with e network dependency to avoid that, but I'm not sure how that'll work if the network fails to come up after a reboot. Then there's all the things I haven't thought of...) -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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Kontact crash
by Phil Thane 19 Jan '18

19 Jan '18

Happy New Year all, here's my first bug of the year. Using Kontact on Mint 18.3 (KDE) it's been fine for ages then yesterday, this: Kontact opens in Kmail which works fine. Choosing other modulkes from the sidebar I find Contacts (Kaddressbook) or Calendar (Korganizer) cause Kontact to crash. Other modules do not. Running from a terminal doesn't provide much info except an invalid socket warning. KCrash: crashing... crashRecursionCounter = 2 Following a crash the app has clearly not exited properly because socket errors keep on coming until I close the terminal. *phil@phil-desktop* *~ $* QSocketNotifier: Invalid socket 53 and type 'Read', disabling... Running Korganizer direct from a terminal is OK. Running Kaddressbook isn't. It opens for a fraction of a second, just long enough to see the window, then crashes. Similar error messages to the above. As I have little idea what a socket is, I'm stumped! The KDE reporting tool reports that the log isn't detailed enough to bother with and I can't find any useful advice online. Help?! -- Phil Thane www.pthane.co.uk phil(a)pthane.co.uk 01767 449759 07582 750607 Twitter @pthane

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 11th January
by Viperfang 09 Jan '18

09 Jan '18

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 11th January at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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2600 meeting at 18:00 on Friday the 5th January.
by Viperfang 04 Jan '18

04 Jan '18

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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Scoring in the Gnome game "Five or More"??
by Ted Harding 26 Dec '17

26 Dec '17

Greetings All! And Happy Christmas and Happy New Year. I am trying to find out what formula is used to determione the scores in the Gnome game Five or More, in which you score BY "lining up" 5 or more counters of the same colour on a 9x9 board. In fact it's a bit more general than that, and any 2 or more intersecting lines, where with your latest move you have made each line contain 5 or more counters all of the same colour, then you get a score which depends on the total number of counters in these lines. Theae counters arre then erased and their cells become empty. For a single line (vertical or horizontal or diagonal) you can score with 5/6/7/8/9 counters. To score more than 9, you need at least three lines, which intersect at a single empty cell into which you then drop a counter of the same colour, combining 2 of the line into a line with 6/7/8/9 and with 4 more in the third ine. Then you score with 10/11/12/13 counters. And, if I've got it right, the biggest number of counters you can score with is when you have 8 lines, each with four counters, intersecting at the centre of the 9x9 square which is still an empty cell; and then you drop a counter into that square, and then you score with 33 counters. The "Help" page for gthe Gnome game says: Number of objects Score given 5 10 6 12 7 18 8 28 9 42 10 82 11 108 12 138 13 172 14 210 so it only goes up to 14 counters. However, as I describe above, one can go higher (up to "Number of objects" = 33. Trying to give this a go, I did succeed in achieving 17 (four diagonal lines with 4, plus 1 for the cell where they meet), and my score jumped from somewhere in the hundreds to 4106; so clearly one can score in the thousands with "Number of objects" = 17. But since I have seen no documentation which tells how many points you score for more than 14 counters, and have not seen any description which describes how the score is calculated from "Number of objects". Does anyone know, or can find out? with thanks, and best wishes to all, Ted.

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New Server Recommendations
by steve-ALUG＠hst.me.uk 21 Dec '17

21 Dec '17

For many years I've been running a 2nd-hand "desktop" machine as a home server, which runs print, file & email services and a few others. It's an least 10 Y/O Pentium (5?) with 3GB RAM and is usually not taxed by these services. I have asked before, but I've never actually got round to doing anything about it, but I've got executive approval from the S/O BUT.... I'm in two minds. Do I go for A) a traditional box, plenty of room, RAIDed disk but comparatively high power consumption e.g. https://www.entroware.com/store/desktops/nyx or https://secure.zeta.systems/store/desktops/D540/ which seem to have PSUs rated about 650W or B) a small NUC style box, low power consumption thingy like https://www.entroware.com/store/desktops/aura or Something like the mini-itx jobbies available here https://www.logicsupply.com/uk-en/products/commercial-computers/mc500-serie… These seem to consume about 65W. I will be running some flavour of Ubuntu on it. I'd probably prefer it was 64Bit. I want it to be a "standard architecture" processor so that there will be a full-range of apps available to install from the ubuntu repositories. I would like to have a low-power-consumption as it's an always on device, and it doesn't seem to need much processing power. I'd also like to have raid (mirroring), but most low power-consumption machines don't seem to have space for raid. Does anyone have any comments or recommendations, especially of any companies they have dealt with, or products they have purchased that work well? Thanks in advance. Steve

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Amber intends to combat encryption!
by Phil Thane 19 Dec '17

19 Dec '17

I've been having 'fun' corresponding with my MP (Burt, con) and our much-loved Home Secretary about her plans to ban encrypted messaging. The gist is here, with links: https://pthane.co.uk/blog/ Scroll back a bit for the first installment. Feel free to register and comment, I don't claim to be an expert, I could well be wrong, but it seems I know more that the Home Office. -- Phil Thane www.pthane.co.uk phil(a)pthane.co.uk 01767 449759 07582 750607 Twitter @pthane

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Restarting wifi and network on a headless Pi
by Mark Rogers 14 Dec '17

14 Dec '17

I don't know if this is Pi specific, I assume it's just standard Debian. I'm using Raspbian Stretch. Suppose I have a working wireless connection. I can change wireless configuration in /etc/wpa_supplicant/wpa_supplicant.conf to remove the working details and then use "wpa_cli reconfigure" to take effect. Except that I remain connected to the wifi that I no longer have settings for, and cannot force it to disconnect. What is the correct way to force the change to have effect other than reboot? On a related note, how do I change the IP configuration for the cabled network and have that take effect? Making changes to /etc/dhcpcd.conf works after a reboot but I can't reliably make it work without rebooting. (Restarted dhcpcd will add a new IP address, but won't remove old ones and doesn't seem to let me revert to DHCP reliably either.) In both cases, making a connection seems easier than dropping one. Mark -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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Are there *any* decent web browsers out there now?!?!
by Chris Green 11 Dec '17

11 Dec '17

I'm finally getting a bit fed up with Firefox, for a couple of reasons:- It's seems incapable of working with eBay without going to 100% CPU and slowly grinding to a halt. The last few updates have made it *look* decidedly clunky. Arcane configuration parameters required to make it so it can open files on one's local file system. So, I've been looking at alternatives and there's not much that seems any better (they have different issues in the main). I've been trying chromium and it certainly seems faster than Firefox and doesn't seem to grind to a halt on eBay, but:- I want a separate search bar You can't change the keyboard shortcuts Is anything else any better? I've been wondering about Vivaldi, same underlying engine as Chromium but apparently much more configurable. Has anyone here tried it? I'm just a bit wary of going 'off piste' as it were (not in the Ubuntu repositories). -- Chris Green

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 14th December
by Viperfang 11 Dec '17

11 Dec '17

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 14th December at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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How to allow easy editing of www-data owned files - or other workarounds?
by Chris Green 11 Dec '17

11 Dec '17

I've been trying to find a good solution to this problem for *years* but I'm still hitting problems with it. The current problem is that syncthing doesn't deal well with directories and files which have different owners on different systems. The essential problem is that web files which are manipulated by apache need to be owned by www-data but I want to be able to edit these files as well. In particular I have a wiki where I sometimes edit the files using the wiki (ownership ends up as www-data) and sometimes I edit them directly with an editor (ownership ends up as chris). Currently I use access control lists (setfacl) to make things so that both chris and www-data can both manipulate files in the wiki directory regardless of whether they are owned by chris or www-data but this isn't a perfect solution as the correct settings don't always get put on new files. What I really need is:- All the wiki files are owned by 'chris' (the wiki is rooted in my home directory and is synchronised across a couple of machines by syncthing). www-data can read/write/create files in the ~/chris/wiki directory but they will always be owned by 'chris'. Can anyone see a way of implementing this? ... or any other reasonable solution? -- Chris Green

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Magnetic resonance?
by Phil Thane 07 Dec '17

07 Dec '17

No this isn't a Linux question but you are the only techie people I know. If there is anyone from a Physics / Electrical Engineering background who can help with or proof read a short paragraph about wireless charging using electro-magnetic resonance, please get in touch off-list. Thanks. -- Phil Thane www.pthane.co.uk phil(a)pthane.co.uk 01767 449759 07582 750607 Twitter @pthane

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Strange postfix problem
by Laurie Brown 07 Dec '17

07 Dec '17

Hi all, Do we have any postfix experts on here? I have a very strange problem I'm struggling to resolve, and I'd appreciate some help. Cheers, Laurie. -- --------------------------------------------------------------------- Laurie Brown laurie(a)brownowl.com ---------------------------------------------------------------------

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Audio Question
by Ben Whyall 05 Dec '17

05 Dec '17

Hi I have a query which whilst not 100% linux I suspect someone might be able to help. I want to be able to somehow share speakers, and headphones/headset between two systems. Ideally I want to be able to decide what output is in use by ficking a switch or something similar not unplugging. Same with the input. One machine is a linux box and one is my work laptop (windows 10) What are peoples thoughts? Ben

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Firefox 57 woe
by Bev Nicolson 30 Nov '17

30 Nov '17

I had hoped to be prepared for whenever the upgrade to Firefox 57 occurred but it turns out I haven't been. This is because the Software Updater hadn't offered 57. Anyway, it seems I have lost all my ScrapBook pages. Or at least, the question I want to ask is, how can I find out for sure that I have? The home and computer directory have been searched for 'firefox data' but no dice. Bev.

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ssh_config file equivalents of command line options - how to find?
by Chris Green 30 Nov '17

30 Nov '17

I had a hard time recently working out what the ssh_config file equivalent of the -L command line option in ssh was. The man page happily tells you that "Port forwardings can also be specified in the configuration file." buut doesn't tell you *what* the configuration file equivalent is. (It's actually a bit obvious - LocalForward). Is there any documented way of finding the mapping? I'm now after the config file equivalents for -f and -N if there are any. -- Chris Green

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2600 meeting at 18:00 on Friday the 1st December.
by Viperfang 30 Nov '17

30 Nov '17

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

1 0

How to *start* a desktop remotely? (for VNC)
by Chris Green 23 Nov '17

23 Nov '17

How can one *start* a desktop (in my case XFCE on xubuntu) remotely? I have set up VNC to acces my home machine desktop but since it's not actually running a desktop as it's been rebooted the VNC client shows me nothing. Help!? I have ssh access to my home machine. -- Chris Green

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4G data
by Phil Thane 19 Nov '17

19 Nov '17

Hi, Not really a Linux question, except that it'll be mostly Linux devices that use it... A few years ago when 4G was being tested in pilot areas, but not on the Llangollen canal, I wrote a piece for a canal/river boat magazine about using the internet afloat. At the time I borrowed some demo kit from suppliers and a boat from the Llangollen Wharf for testing and for photos. One option was a 3G USB dongle for a laptop, another was a 3G modem/router to create a WiFi hotspot. Or just use my old 3G smartphone and either a USB or WiFi 'tether'. Now down south I've got my own (very old and very cheap) boat and 4G is widely available. So should be great eh? Well not so much. As far as I can find out it is impossible to buy data only SIM cards with data contracts that last until the data is used. You have to buy 'bundles' of data/phonecalls/text and they expire after 7, 14 or 28 days. When I'm not on the boat I don't use 4G at all. When I am going away on it I have to guess how much data I might need and load up the SIM. Last time I did that the boat broke down, we came home early and £20 worth of data just expired at the end of the 28 days. With my old 3G phone (on PAYG) it simply used the same account for texts, calls or data - and I only enabled 3G when I really needed it. But it seems none of the phone providers will offer 4G that way. I can't see there's any technical reason, it's just that phone providers are conniving bastards. Does anyone know of one that has broken ranks with the cartel and will offer me what I want? -- Phil Thane www.pthane.co.uk phil(a)pthane.co.uk 01767 449759 07582 750607 Twitter @pthane

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