view youtube videos while browsing with elinks

I recently wanted to view a youtube video using a computer that had no graphical browser installed. Long story short, the computer runs Gentoo and is used almost exclusively for recording and playback of television content: so for almost all use case scenarios, having a graphical browser is not needed, the excessive compile times they would entail (over 24 hours on this somewhat low-resource machine) being unjustifiable.

I decided there must be some way, using the non-graphical browser I did have on this machine--elinks,to view youtube videos. A bit of online research revealed how I could accomplish this task. Though there is undoubtedly more than one way to skin this cat, I used the one that seemed most straightforward to me, as described below.

Since I already had installed the mpv utility, all I had to do was some minor tweaks to elinks. First, I went into Setup > Option manager > Document > URI passing and added a new entry. I simply named it youtube-handle_mpv. Of course the final task for this step is to save that option.

I then edited that entry, using information found at the Arch wiki entry for elinks, and added the line mpv %c (this allows elinks to feed the designated URI to mpv). Having done that, I next needed to assign a key which, when pressed, would trigger the URI passing.

I went to Setup > Keybinding manager > Main mapping > Pass URI of current frame to external command and there designated the grave or backtick key as the one that would trigger the URI passing. Again I selected "save" and exited the Setup menu.

After having done that, I navigated elinks to youtube's site, searched for the video I wanted to view and, having highlighted the desired link using the arrow keys, pressed the grave/backtick key. After a brief pause (for downloading and caching some of the data, I presume), mpv opened and the video began to play.

NOTE: the pause between pressing the designated key and the actual playback of the video under mpv could vary based, I believe, on the length/quality of the video.

Stress-testing hard drives

This entry will consist mostly in someone else's content. The back story is that, about 3 years ago on the mythtv-users list-serv, one of the list members offered such a concise, straightforward, and apparently sound description of how she tests out new hard drives, that it remained in my memory.

Well, now that it has come time for me to replace an aging hard drive in my MythTV machine, it's time to dig out those directives and actually use them. And while I'm doing that, I may as well post them on this blog for future reference. Credit for the material goes to faginbagin/Helen, the user who posted it in the list-serv.

Without further ado, here is the content:

I look for drives with the longest warranty. This Christmas I bought 4 3TB HGST drives with 3 year warranties. Got to look close, because some only have 2 year warranties. Before I put any new drive into service, I use the following procedure to increase the chances it's a good drive
that will last. 

Capture SMART data via:
smartctl -a /dev/sdx > smart0.out 

Write semi random data on the whole drive with:
nohup shred -n1 -v /dev/sdx > shred.out & 

Go away for a couple of hours. Check shred.out and figure out how long
it will take to finish. Come back when it should be done. 

Read the whole drive and compute a checksum:
nohup md5sum /dev/sdx > md5sum.out & 

Go away for roughly the same time it took shred to write to the drive.
Read the whole drive again and make sure the checksum matches:
nohup md5sum -c md5sum.out > md5sum.chk & 

Go away for roughly the same time it took the first md5sum to read the
drive. 

Write zeros to the drive:
nohup dd if=/dev/zero of=/dev/sdx bs=1M > dd.out & 

Capture SMART data via:
smartctl -a /dev/sdx > smart1.out 

Compare the two smart runs:
diff smart0.out smart1.out 

Make sure there are no complaints about sectors. 

Make sure the kernel didn't report any errors:
dmesg| tail 

If no SMART or kernel reported errors, create partition table, create
partitions, mount, etc... 

If any errors, return immediately. 

 Original post located at http://lists.mythtv.org/pipermail/mythtv-users/2016-April/386438.html

dhcpcd hooks: what are they and why should you care?

I know I didn't know what dhcpcd hooks were and why I should care about them. That is, until I set up a file server that runs headless and which I want to make sounds when certain events, such as the network coming up, occur. This, as may be evident, will help me ascertain whether, in absence of a monitor displaying graphical indicators, the machine booted and came online successfully--a pretty important status for a machine like a file server.

dhcpcd (the final "d" stands for "daemon") is, of course, the utility that runs on a lot of Linux computers in order to get them connected to the network. It polls for an IP from whatever dhcp (dynamic host configuration protocol) server is running on the network, and the IP received gets assigned to the computer's designated network interface. So the "hooks" under discussion essentially latch onto that process and cause some other process(es) to be triggered once dhcpcd accomplishes its task. This, then, could allow me to implement the desired behavior on my headless file server

I had part of the solution in place already, namely the beep program, a utility that allows for the playing of various tones through the pc speaker. Yes, I'm aware that most computer users seem to want only to disable the pc speaker: I, on the other hand, have found it quite useful on my systems.

Having done some on-line research on this matter, I was able to succeed at the task of getting the pc speaker to play a tone once the computer had booted and gotten an IP by using the following steps (geared toward the Void Linux distribution installed on that target system).

I first created a file owned by root and in the root group in /usr/share/dhcpcd/hooks/--(call it, say) 10-beeponIP--with the following content:

if ([ $reason = "BOUND" ] || [ $reason = "RENEW" ]) then
# your script commands here (see below for the command I used)
/usr/bin/beep -f 1000 -r 5 -n -r 5 -l 10
fi

I can't go into many specifics of the bash syntax seen in this file since I understand it rather poorly myself (it was simply lifted from the askubuntu link listed below). But some testing of its claimed efficacy revealed that it would, in fact, result in the behavior I was aiming to enable.

I had to set proper permissions on that file, then symlink it. Doing the former was straightforward (permissions needed are, like the rest of the files in that directory, 444). I ran the following command to create the needed symlink: sudo ln -s /usr/share/dhcpcd/hooks/10-beeponIP /usr/libexec/dhcpcd-hooks.

Having done that, on rebooting the computer, the designated tone plays though the pc speaker, letting me know that the system booted normally and is now on-line. Mission accomplished!

Some links that helped me to better understand and accomplish this task are given below:

https://askubuntu.com/questions/1005653/how-do-i-execute-a-script-after-dhcp-assigns-an-ip-address-on-start-up
https://wiki.voidlinux.eu/Network_Configuration#Starting_wpa_supplicant_through_dhcpcd_hooks
https://man.voidlinux.eu/dhcpcd-run-hooks.8