main January 2011

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32 participants
46 discussions

Wanted - simple way to check mains power is available
by Chris G 29 Jan '11

29 Jan '11

I'm looking for the simplest possible way for a script (or any sort of program, can be C, Python, whatever you like within reason) to check whether mains power is on. The computer which is going to check this is running off batteries so will still be running (I'm not quite that stupid!). The easiest way I can think of at the moment is to have some sort of hardware with a presence on the LAN powered by mains so that one can ping it to check that mains power is there. However the 'simplest' device I have at the moment is an old router which seems rather overkill for such a simple requirement. Can anyone think of any better way of doing this for which I am likely to have the hardware available or which will cost very little? I'm quite happy to build simple bits of electronics. The computer running the check is an old eeePc so has only USB and ehternet connections as far as I remember. -- Chris Green

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How to copy a file (using rsync or scp) only if the file exists?
by Chris G 26 Jan '11

26 Jan '11

I have an rsync copy command as follows:- rsync --remove-source-files cheddar.halon.org.uk:odin/tempdata ~/odin This copies tempdata from the remote system to the local system and also removes it from the remote. The file tempdata is put there by a cron job and I want to process the data once only and then wait for new data. This is fine as long as the cron job putting data onto the remote system runs every hour and the local rsync also runs every hour. However if the remote cron job fails then, although I don't process the data again, I get a "No such file or directory" from rsync. I suppose I could just throw the error message away but that would throw other error messages away too which might be important ones. Any ideas? -- Chris Green

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Recommendations wanted for simple, command line, webcam capture program
by Chris G 24 Jan '11

24 Jan '11

I'm after a simple webcam image capturing program to run from the command line (well, ultimately from cron). It's to run on my eeePc on the boat so must be simple and lightweight. I am currently trying webcam and fswebcam without much success at the moment. If anyone has any experience of either of these programs then I'd be pleased to know. It seems that webcam is the nearest to working, I'm am trying to get it to store images locally rather than FTPing them anywhere. It seems to grab an image but then when it tries to copy it fails:- root@eeepc:~# mkdir -p /home/chris/public_html/images root@eeepc:~# webcam reading config file: /root/.webcamrc video4linux webcam v1.5 - (c) 1998-2002 Gerd Knorr grabber config: size 320x240 [none] input (null), norm (null), jpeg quality 75 rotate=0, top=0, left=0, bottom=240, right=320 write config [ftp]: local transfer /home/chris/public_html/images/uploading.jpeg => /home/chris/public_html/images/webcam.jpeg open filename: No such file or directory open filename: No such file or directory open filename: No such file or directory open filename: No such file or directory -- Chris Green

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Superblock problem
by Ted.Harding＠wlandres.net 23 Jan '11

23 Jan '11

Greetings All! I have hit a big snag. On an old machine, I have a hard drive /dev/hda. I had to re-set the machine it when it seized up just now. On re-booting, it went of course into fsck and then announced: fsck.ext2: No such file or directory while tryin to open /hda1 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid, and really contains and ext2 filesystem ... then the superblock is corrupt and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> ... fsck failed. Please repair manually and reboot. The root filesystem is currently mounted read-only. To remount it read-write do: .... At this point, [**] I logged in with the root password, and ran fdisk /dev/hda1, and I got blanks for all the fields. When I ran fdisk /dev/hda, I got Device Begin Start End Blocks Id System /dev/hda1 1 1 1024 822525248+ 83 Linux Native which looks right. I then ran the suggested "e2fsck -b 8193 /dev/hda1" alternative, and it went through the familiar series of checks and asked for approval for the familiar set of corrections. All semed to go well. Then it came boot to the root prompt "#" and, as usual, I pressed Ctrl-D to log out and reboot. Now, on re-boot, I get the same as before down to [**] above, and this time I do e2fsck /dev/hda1 and this time I get: /dev/hda1: clean, 213963/2058240 files, 3193368/8225248 blocks So it looks as though it succeeded. Now I again do Ctrl-D to reboot. But, on re-boot, I again get exactly the same as first time down to [**] above. So it is as though the superblock has not been fixed (though apparently the alternative superblock was fixed). SO: QUERY: How can I try to fix the superblock and get it booting normally? With thanks for any good suggestions! Bes wishes to all, Ted. ---------------------------------- E-Mail: (Ted Harding) <Ted.Harding(a)wlandres.net> Date: 22-Jan-2011 Time: 23:13:49 This message was sent by XFMail ----------------------------------

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Re: [ALUG] Ubuntu help
by Chris Walker 21 Jan '11

21 Jan '11

On 17/01/11 16:06, keithjamieson(a)hotmail.co.uk wrote: > > I'm trying to persuade a Virtual Ubuntu installation to talk to a > > Windows 7 host. > > > > What's frustrating is that one share works but another doesn't and I > > can't see why, other than the 'Protocol error' which is displayed. > > > > Is there somewhere on the virtual machine where this stuff is logged so > > that I can perhaps see what's going wrong? > > Only in the syslog of the virtual machine. I dont think there are > anything in the VM "program" to help. But I'll probably be proved wrong > in the next post! > > > I've looked in the syslog but that doesn't show any networky-type errors. > > Do both have the correct IP addresses AND netmasks? > Can they ping each other ? > Can you install Wireshark to see if packets are being received by the > other machine? > Does this install use the PC host as the NAT address, or the virtual > machine use a similar IP address? > Are there firewalls running on either of the machines? Before I answer those questions, can I just point out one thing that I mentioned above? One share is working fine. It's when trying to create another that it's failing. > Can you try a pre-rolled small VM, like Puppy ? Yes I can and have but didn't try multiple shares. I'll give that a go though to check. I'm writing this under Mandriva. There I can run Windows XP as a guest and despite having multiple shares on the host machine, in XP it will only allow me to have one share to a NAS drive - there are 4 shares to that under Mandriva - so I'm wondering if it's a Windows limitation that's preventing me having two shares to the host machine. I realise that this isn't the place to ask Windows questions so I won't pursue that here. -- __ __| |_ __ __ .----------------------------------------------. / _/ _` \ V V / | mailto:cdw_alug@the-walker-household.co.uk | \__\__,_|\_/\_/ |______________________________________________|

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sdb1
by Simon Royal 20 Jan '11

20 Jan '11

Hi When I boot my ThinkPad in to Ubuntu it gets stuck. It flashes on a screen and says something like unable to find sdb1. I have to press S to skip mounting it and continue booting. It is annoying. I think this has something to do with Storage Device Manager which I use to automount a FAT32 partition - which I use as shared storage for my files. I dual boot Ubuntu and XP and have a spare partition to put everything. I looked in Storage Device Manager and could find no reference to sdb1. sda1 = xp sda2 = ubuntu sda3 = swap sda4 = fat32 shared partition. sda4 is set to automount with correct rw permissions. This works fine. Any ideas? Simon -- --- Twitter: http://twitter.com/SimonRoyal - LowEndMac: http://tinyurl.com/macspectrum - Skype: Simon-Royal. --- IBM ThinkPad R31 running Ubuntu 10.10 & Windows XP Home. Apple PowerBook G3 'Pismo' running OSX 10.4. Sony Ericsson Xperia X10 Mini Pro running 2.1

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Hang on resume from suspend to disc in 2.6.35
by Dan 20 Jan '11

20 Jan '11

Dear All, My Acer Aspire One, with the kernels known in Gentoo as 2.6.35-gentoo-r4 or 2.6.35-gentoo-r12, hangs on resume from suspend to disc - after counting up to 100% and printing the message "Suspending consoles (use no_console_suspend" to debug". Suspend/resume works fine with kernel 2.6.34-gentoo-r6. The 2.6.35 kernel configs were generated from the 2.6.34 kernel config using "make oldconfig". Firstly: does anyone immediately know what the problem is, please? If not: how do I persuade suspend/resume to produce an informative log file to help with diagnosis, given that the whole process happens while klogd and syslogd are stopped? -- Thanks, Dan

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Internal Broadcom
by Simon Royal 18 Jan '11

18 Jan '11

Hi I am trying to get a permanent wireless solution for my R31. I have a variety of devices that work under Ubuntu but some have issues. USB Zydas stick - it works fine, but is taking up my only free USB port (as I broke the other). Edimax PCMCIA card - hangs the machine when on battery. Buffalo PCMCIA card - works great, but is my sons. Intel Mini PCI card - hangs the machine after a few mins. So far - apart from the USB stick - the Buffalo card which is Broadcom 4306 based card has been the most reliable. Whilst scouting around on eBay I found a Broadcom based Mini PCI card which uses the same chipset. Are the problems I have with my other internal card - the Intel 2200BG - related to my particular card, those Intel cards or Mini PCI cards in general? Would a different card suffer from the same problems? I know you cant really answer it, but does anyone have any experience or problems with other internal wireless cards. It is only a few pounds so I wont lose too much if it doesnt work when it gets here. Simon -- --- Twitter: http://twitter.com/SimonRoyal - LowEndMac: http://tinyurl.com/macspectrum - Skype: Simon-Royal. --- IBM ThinkPad R31 running Ubuntu 10.10 & Windows XP Home. Apple PowerBook G3 'Pismo' running OSX 10.4. Sony Ericsson Xperia X10 Mini Pro running 2.1

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DD-WRT VPN settings
by Ricky Bruce 18 Jan '11

18 Jan '11

Somewhat off topic but as dd-wrt is Linux based i tenuously justify it to myself. I use strong vpn along with a dd-wrt flashed router to create two seperate wifi SSID's from the same router. One is my standard wifi and routes all traffic normally through my UK IP. The other redirects it through the VPN through virtual network vlan3 and is used to access USA based services such as Netflix on devices that lack the ability to run a VPN client. (Dare i say Apple TV?) I followed the instructions in the strong vpn forum (http://strongvpn.com/forum/viewtopic.php?id=806) to get it up and running and for the most part it is working great. However on occasion the router seems to drop the VPN connection and revert to the UK ip. Rebooting the router does not on its own fix it, neither does setting the router to reboot periodically once a day. The only way i have found so far to reliably establish contact with the VPN is to edit and then resave the firewall script, and then power cycle the router. I use Mint at home, and while i have been using Linux for sometime i have been lucky enough to never really have to go beyond configure; make; make install when using my machines, so my scripting knowledge is severely limited. Can anyone suggest any ways to make the router detect when it has dropped the VPN connection, reload the required script and reboot? Below is the copy of the firewall script that is in its current form. VPN_IPUP=/tmp/pptpd_client/ip-up grep -v "exit 0" /etc/config/pptpd_client.ip-up > $VPN_IPUP echo ' sleep 15 # Load ebtables for i in ebtables ebt_mark ebtable_filter ebtable_nat; do insmod $i; done # Clean up ebtables -t nat -F ip rule del from 0/0 fwmark 4 lookup 4 ip route flush table 4 # Hack: take QoS down (but we need it enabled for ebtables) iptables -t mangle -F # Set up ebtables -t nat -A PREROUTING -i wl0.1 -j mark --set-mark 4 ebtables -t nat -A PREROUTING -i vlan3 -j mark --set-mark 4 ip route show table main | grep -Ev ^default | while read ROUTE; do ip route add table 4 $ROUTE; done ip route add table 4 default dev ppp1 ip rule add fwmark 4 table 4 ip route flush cache ' >> ${VPN_IPUP} chmod +x ${VPN_IPUP} Kind regards, Ricky

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[ALUG Announce] 3rd Monday Monthly Ipswich Social Meeting : McGintys, Northgate Street
by samwise 17 Jan '11

17 Jan '11

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via http://lists.alug.org.uk/mailman/listinfo/announce ----- The monthly "Third Monday" ALUG Ipswich Social Meeting is back next week, Monday 17th January, at 20:00: P J McGinty & Sons 15 Northgate Street Ipswich Suffolk IP1 3BY Tel: 01473 251 515 Map/Directions URI: http://maps.google.co.uk/?q=IP1+3BY WWW: http://www.pjmcgintys.co.uk/ McGintys pub is in the centre of Ipswich. It's directly opposite the town's central library and has a reputation for good Irish beer. We're usually to be found in the lowest section of the bar, near the library entrance to the pub. All are welcome, novices and experienced users. Feel free to ask for further information on the Main ALUG mailing list. Hopefully, see some of you there! Peter. ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via http://lists.alug.org.uk/mailman/listinfo/announce

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main January 2011