- Roundtable - muug.ca

Hide mouse cursor in Wayland, labwc compositor?
by Gilbert Detillieux 07 Apr '25

07 Apr '25

Hi folks. I'm trying to find something equivalent to "unclutter" or "xbanish" that will allow me to hide the mouse cursor when I'm running Wayland's labwc compositor. This is for a kiosk-mode application, using a Raspberry Pi and Debian 12 (Bookworm). Thanks! Gilbert -- Gilbert Detillieux E-mail: Gilbert.Detillieux(a)umanitoba.ca Computer Science Web: http://www.cs.umanitoba.ca/~gedetil/ University of Manitoba Phone: 204-474-8161 Winnipeg MB CANADA R3T 2N2 For best CS dept. service, contact <cs-support(a)lists.umanitoba.ca>. _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Google Play Pass
by Trevor Cordes 07 Apr '25

07 Apr '25

My daughter likes to play some kid/toddler games on our Android tablet. I have banned ads from our home. Anyone who's tried to find games on Android will know that 99% of the free games (and even some for-pay games) have ad quantities that would put the worst of network TV to shame. And the ads are often very inappropriate. Plus, her attention span for these games is the size of a grain of sand, so we needed a faster way to find and cycle through games. So we used the excellent "App Finder" app (which I highly recommend) on the play store which did an ok job when you click the "no ads" button. This works ok, but we started getting down to just the for-pay games. And paying $1-$5 a game for the pay games doesn't sound too bad, except 90% of them she'll play once for 2 minutes and then never play again, making the purchase a waste. (There's no way to know whether a game will not interest her without paying & playing!) So we're giving the google Play Pass subscription service a try, mostly because we can try basically every for-pay play-pass game for free and throw the bad ones away with no remorse, AND it promises NO ADS. Like NO ADS EVER on badged play-pass games. Ya, so my son chose 3 promising play-pass games at random and all 3 of them instantly had ads galore. Basically nothing changed. So those instantly got uninstalled... I verified that I am indeed looking at "Play Pass Badged" games, that say "Play Pass" and have the icon, and are in the Play Pass-only section of the Play Store. I'm wondering if anyone else has play pass and can verify if all or some of their games did or did not have ads. Maybe there's something broken on the tablet, especially because it's in "supervised" (child) mode which seems to make things a disaster. (Google really hasn't tested all use / family scenarios.) Maybe I have to jump through some extra hoops somewhere? I can't believe that this is google's actual flagship mobile software product they are pushing. I'm not going to pay for it if I'm back to square one having to vet 9 games to find 1 that for realz doesn't contain ads. I'm buying it for the sole purpose of saving time. (P.S. It's $35 a year with an automatic 1 month free trial -- I have 30 days to cancel if I can't sort this out. P.P.S. You can apply the pass to every device in your "family group" so that's a bonus.) _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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closures
by Trevor Cordes 03 Apr '25

03 Apr '25

It dawned on me that in perl you can create a closure without even nesting functions (though you can also do it the "traditional" way). Perl allows you to have unnamed blocks that define their own variable scope, which can take the place of the outer function in giving you the local/protected variable you need. Of course this has the downside of only giving you one closure instance per definition/generator, instead of letting you call the generator multiple times to get multiple instances. But in many cases you just want one instance anyhow. P.S. The slides & code examples for the closure presentation will be up on the web site by tomorrow(ish). https://muug.ca/meetings/24-25.html#apr #!/bin/perl -w my $inc; { my $counter=0; $inc=sub { $counter++; print "$counter\n"; }; } $inc->(); $inc->(); $inc->(); print "$counter\n"; # Alberto shields up! _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Re: Reminder: MUUG Meeting, Tonight, Apr 1, 7:30pm (In-person/Hybrid Meeting) -- Programming With Closures, RTFM: /bin Diving
by Sean 02 Apr '25

02 Apr '25

Caution! This message was sent from outside the University of Manitoba. Greetings y'all, (I hope this is the correct venue for asking a 'group question'.... If I'm doing this wrong I'm prepared to take my lumps at tonight's meeting!) I have a number of smaller projects here, some of which are 'in the middle of' using Pi's and/or Arduino's that I'm asking if there's anyone who's adept at this stuff (some connected to Linux server) who's willing to assist me at your leisure? The person to whom I'd started these projects with, has "removed themselves from society" and I'm not afraid to admit that I need help with the digital end of things. Let me know if you're willing to assist, and we can definitely work something out. I'm only asking for those who're interested and able; as I'm not asking for voluntary work. Sean On 2025-04-01 16:28, Gilbert Detillieux wrote: > A reminder that the MUUG meeting will be this evening, both in person > and online... > > The Manitoba UNIX User Group (MUUG) will be holding its next monthly > meeting IN PERSON, on Tuesday, April 1st, at 7:30pm. Yes, that's the > FIRST Tuesday of the month... > > Programming With Closures > > Unknown by many programmers, closures and first-class functions > enable some pretty cool programming techniques that can make your > code more maintainable. In a short presentation, Trevor Cordes > will demonstrate what they are, how to use them, and explain why > they can be desirable. > > RTFM: The Return of /bin Diving! > > Our first couple instalments of /bin Diving were a big success, so > we'll do it again! Everyone in attendance will be encouraged to > help Brad Vokey bumble about on the command line to figure out how > to use a random /bin program. > > April Door Prize > > Along with our usual selection of e-books, Wyatt Zacharias has > acquired for MUUG two Pi Zero W 2's along with two Pi SD cards for > us to give away! One set was given away at the March meeting, and > the other will be in April. > > Where to find the Meeting: > Fortress Software Inc., 350 Keewatin St -- Unit #2 > > We have a new in-person meeting location now! Brad Vokey has > graciously let us use his work office for our next in-person > meeting. The meeting room will be open by 7:00 pm, with the actual > meeting starting at 7:30 pm. If driving, enter the lot using the > most north east entrance and drive around to the south west corner > of the building (see route in map detail on poster linked below). > You can use any of the free, ample, and safe parking spots that > say "reserved" in front of units #1 through #4 before entering > unit #2. Bus stops #30814 and #30880 (route 77) are only 150 > meters away. The last bus leaves for Polo Park at 10:15 pm and for > Garden City at 10:31 pm. Logan Ave. bus routes #19, #26, and #27 > are a 600 meter (8 minute) walk to the south. > > For those unable or preferring not to attend in person, the > meeting will also be available online, using BBB as usual. Stay > tuned to our muug.ca home page for the official URL, which > will be made available about a half hour before the meeting > starts. (Reload the page if you don't see the link, or if there > are issues with connecting.) > > The group now holds its meetings at 7:30pm on the *first* Tuesday of > every month from September to June. (There are no meetings in July and > August.) Meetings are open to the general public; you don't have to be > a MUUG member to attend. > > For more information about MUUG, and its monthly meetings, check out > their web server: > > https://muug.ca/ > > Help us promote this month's meeting, by putting this poster up on > your workplace bulletin board or other suitable public message board, > or linking to it on social media: > > https://muug.ca/meetings/MUUGmeeting.pdf > _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Raspberry Pi Zero 2 W case and accessories
by Gilbert Detillieux 05 Mar '25

05 Mar '25

For any past or future winners of our Raspberry Pi Zero 2 W boards as door prizes, or anyone else who's bought one, here's the bundle deal I got on Amazon last year (that I mentioned to some of you at yesterday's meeting)... https://www.amazon.ca/iRasptek-Raspberry-Zero-Essential-Accessories/dp/B0BY… It's unfortunately marked as "Currently unavailable", and I don't know if it will come back or not. There are other bundle deals out there if you search, but I haven't seen anything as low as what I paid ($17 + taxes) with that many accessory cables/adapters included. Gilbert -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.ca> Manitoba UNIX User Group Web: http://muug.ca/ _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Monitoring sensors not supported by net-snmp
by Gilbert Detillieux 05 Mar '25

05 Mar '25

Thanks, Wyatt, for a great presentation last night! It provided a great overview and demo of monitoring I2C sensors on a Raspberry Pi, via GPIO pins. You mentioned that some of the sensors visible to libsensors/lm-sensors are made available to net-snmp via particular MIB OID's, but not all of them. If you want to monitor any sensors that aren't directly available in net-snmp (e.g. in LibreNMS), there is a way around that, using net-snmp's "extend" mechanism, and a helper script, such as this one... https://docs.librenms.org/Extensions/Applications/Raspberry%20Pi%20GPIO%20M… You would download the rpigpiomonitor.php file as recommended, as well as the provided sample rpigpiomonitor.ini file, which you would then edit as needed for your particular sensor(s). For example, this is my INI file for monitoring temperature and humidity from a DHT22/AM2302 sensor (not I2C based, but there is a kernel dtoverlay module for it): ; Example configuration which reads a temperature sensor [sensortemp] type = temperature description = AM2302 Room Temperature lowlimit = 0 lowwarnlimit = 15 warnlimit = 32 highlimit = 40 external_gpio_reader = /etc/snmp/Get_DHT_fp_temp.sh ; Example configuration which reads a humidity sensor [sensorhum] type = humidity description = AM2302 Relative Humidity lowlimit = 0 lowwarnlimit = 4 warnlimit = 65 highlimit = 90 external_gpio_reader = /etc/snmp/Get_DHT_fp_hum.sh The "external_gpio_reader" variable is set to a program or script file (it has to be a file, as the PHP code tests to see if the file exists before trying to run it) which would provide a single numerical value as output, corresponding to a specific sensor. Since you can't pass arguments to the program/script, you would typically need a separate wrapper script for each sensor. (Of course, you can use multiple links to the same script, and use the script name as an implicit argument to the shared script.) Hope this helps! Gilbert -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.ca> Manitoba UNIX User Group Web: http://muug.ca/ _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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MUUG Meeting, Tuesday, Mar 4, 7:30pm (In-person/Hybrid Meeting) -- Raspberry Pi Sensors
by Gilbert Detillieux 25 Feb '25

25 Feb '25

Caution! This message was sent from outside the University of Manitoba. The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting IN PERSON, on Tuesday, March 4th, at 7:30pm. Yes, that's the FIRST Tuesday of the month... Raspberry Pi Sensors Wyatt will present I2C sensors on a Raspberry Pi. While many have come to use the Raspberry Pi simply as a mini linux computer with regular USB peripherals, one of the unique features of the Pi is its 40 GPIO pins which include support for the I2C (inter-integrated circuit) protocol. This low level communication protocol opens a wide array of small sensors available for use with the Pi. Wyatt will demo the basics of connecting I2C sensors to the Pi, and some of the software that can interact with them. March Door Prize Along with our usual selection of e-books, Wyatt Zacharias has acquired for MUUG two Pi Zero W 2's along with two Pi SD cards for us to give away! One set will be given away at the March meeting, and the other in April. Where to find the Meeting: Fortress Software Inc., 350 Keewatin St -- Unit #2 We have a new in-person meeting location now! Brad Vokey has graciously let us use his work office for our next in-person meeting. The meeting room will be open by 7:00 pm, with the actual meeting starting at 7:30 pm. If driving, enter the lot using the most north east entrance and drive around to the south west corner of the building (see route in map detail on poster linked below). You can use any of the free, ample, and safe parking spots that say "reserved" in front of units #1 through #4 before entering unit #2. Bus stops #30814 and #30880 (route 77) are only 150 meters away. The last bus leaves for Polo Park at 10:15 pm and for Garden City at 10:31 pm. Logan Ave. bus routes #19, #26, and #27 are a 600 meter (8 minute) walk to the south. For those unable or preferring not to attend in person, the meeting will also be available online, using BBB as usual. Stay tuned to our muug.ca home page for the official URL, which will be made available about a half hour before the meeting starts. (Reload the page if you don't see the link, or if there are issues with connecting.) The group now holds its meetings at 7:30pm on the *first* Tuesday of every month from September to June. (There are no meetings in July and August.) Meetings are open to the general public; you don't have to be a MUUG member to attend. For more information about MUUG, and its monthly meetings, check out their web server: https://muug.ca/ Help us promote this month's meeting, by putting this poster up on your workplace bulletin board or other suitable public message board, or linking to it on social media: https://muug.ca/meetings/MUUGmeeting.pdf -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.ca> Manitoba UNIX User Group Web: http://muug.ca/ _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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systemd-private PrivateTmp unwritable suddenly
by Trevor Cordes 08 Feb '25

08 Feb '25

RHEL9.5 box, fully updated. On a working system with no relevant (systemd/php/apache) updates in 2 weeks, all of a sudden php-fpm process(es) cannot write to its systemd PrivateTmp (forced by default) /tmp/systemd-private-*-php-fpm.service-* This caused fatal errors in the lowest level of a php site during simple logging, as tempnam was returning false when it really never should. I try really hard to work within the systemd paradigm on many things, especially when on paper it sounds helpful, like PrivateTmp. And it worked fine for many years. But now it suddenly does this and screws over a live web site. So it's PrivateTmp=false for me now! I've written all scripts using proper tmp file naming techniques, like php's tempnam (which uses secure code under the hood, or so I'm told). And there's no local users on the box anyhow to start trying to race symlinks, and no user-supplied input is used to create file names. So the whole idea of PrivateTmp to me is "meh". But I want to try to understand what happened here. There are a few oddities. systemd seems to make 2 privatetmp dirs in /tmp for php-fpm(?), yet when this bug hit only 1 existed(?). I suppose systemd-tmpfiles-clean or something may have screwed up and removed the dir? Everything is set to defaults for clean. And the dir seems to have existed via my in-script tests (see below). Most weirdly, the bug only hit one of the php-fpm pools we run! The other main one seemed to be able to write just fine!!?? This is especially confusing since there is only one "php-fpm: master process". There does not seem to be a separate master for each pool, so how could one pool work fine and not the other? There are separate pool worker processes, however. I guess php-fpm could somehow "speak" to systemd to tell it it needs 2 privatetmps, one for each pool? But I don't see how that could happen. Maybe the 2 dirs is a red herring. My personal box doesn't have more than 1 dir for php-fpm, and I have 3 pools. I added debugs to my scripts while the problem was still happening just to confirm the scripts were seeing the tmp dir properly and it was writable, etc. And it was: drwx as detected by php's is_writable, etc. And the subdirs systemd creates are rwxt (sticky, like normal /tmp). However, I couldn't figure out a way for the script to figure out what its real tmpdir was, as it is tricked by systemd into believe the subdir is just /tmp. However, the script saw a dir and thought it was writable and showed me its inode data with ls -l. Since I cannot reproduce the bug easily now that I've restarted php-fpm, and now that I've disabled PrivateTmp because I need 100% trustworthy tools on a production box, I will probably never know what really happened. That is why I plead for MUUGers to pick their brains trying to figure out how a script can see a dir inode and detect it's drwx by the current user and yet any write to it fails.... I know systemd is doing crazy wacky new-fangled mount or namespaces or cgroup or whatever tricks to make PrivateTmp work at all. (And it's slightly evil that there can be a dir sitting right there I can ls at the command line and all perms show I can write to it and yet even root cannot!) _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Among other steps, Will U take 5 minutes by 4 p.m CST TODAY to preserve your right select Canada's next PM?
by eh＠eduardhiebert.com 28 Jan '25

28 Jan '25

In a time when we may experience many difficult circumstances locally and internationally, Hope this email finds you well! As a first next step among several: i) Over the last many days I made the following call to action and now pass on to you as well. Will U take 5 minutes by 4 p.m CST today to preserve your right to select Canada's next PM? Canadians who will be 14 years old or older on March 9 have the right to join the liberal party and thereby have the vote to choose Canada's very next PM on March 9. With the deadline later today please hurry. Without paying a dime you may register at https://liberal.ca/register/ Please note, this does not obligate you to vote liberal in the next election, only preserving your right to help select Canada's next PM! ii) Elections are usually the time when candidates are most open to discussing things of interest to ordinary constituents. Accordingly as an opportunity to push/pull the various candidates, with so many problems in the IT world, would the MUUG executive be interested framing concerns and questions directed at all the candidates of which one with 100% certainty will be Canada's next PM, even if only for a few weeks? This process could then serve as a warm-up as we do the same thing in the next upcoming election where we again have an opportunity to get the ear of the various party leaders seeking to gain electoral power on behalf of us the wider community? iii) I just spent the last 3 hours saving a lot of my open windows content as I needed to reboot before I could open yet another window to submit this request. Luckily Foxy Tab within Firefox makes one of these tasks easy and the url and subject line of all open window can be copied and pasted by one simple copy and paste. However only Wordstar to my knowledge has a non-document mode that can in one simple pass fix the copy and paste of the info just referenced as Foxy Tab does not register a carriage return, only line feed between the various open tabs copied making for an almost unintelligible document. In this round about way I ask is there a PDF reader that can search multiple documents for a key word or phrase? Preferably and possibly placing all results in an easy to use new file and referencing the source document? With my thanks and Best as we work for a better world! Eduard _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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Does the Linux world have the equivalent of Windows Phone?
by Hartmut W Sager 21 Jan '25

21 Jan '25

Does the Linux world have the equivalent of Windows Phone? By that, I am referring to the facility in Windows 11 (and 10?) to connect, via Bluetooth, to a turned-on mobi phone, and to make/receive calls and texts on the Windows Phone desktop app (using a full keyboard, screen, and mouse, of course!). Alternatively, a similar piece of Linux software that connects to a turned-on mobi phone via a LAN that both devices are connected to, might also be suitable. Hartmut _______________________________________________ Roundtable mailing list -- roundtable(a)muug.ca To unsubscribe send an email to roundtable-leave(a)muug.ca

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