Cerin's questions

How do you disable the screensaver/powersave function in Ubuntu 18.04?

In Ubuntu 16, you disabled the screensaver in two steps:

1. First, opening the screensaver gui and selecting "none". But this alone didn't stop the monitor from blanking.
2. The X server had its own powersave feature that would turn off monitor output when nothing on the screen changed. To disable that, you had to run xset s off.

In Xubuntu 18.04, the second part no longer works. Even though I've run xset s off, my monitor output still blanks if nothing changes after a few minutes. How do I fix that?

I'm running the XFCE desktop, with the xubuntu-desktop package, if that matters.

How do you fix rotated video in Pitivi?

When I import video clips into my Pitivi project, they all show up in the correct orientation in the "Media Library" thumbnails, but when I drop them into a track, they'll often appear rotated 90 or 180 degrees, and there doesn't seem to any obvious way to change this.

If I view the video outside of Pitivi, say, in Totem or VLC, the video appears in the correct orientation. Why is Pitivi mangling my video clips, and how do I fix it?

If I try to install mongo on Ubuntu 14.04 with:

sudo apt-get install -y mongodb-org

I get the error:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 mongodb-org : Depends: mongodb-org-shell but it is not going to be installed
               Depends: mongodb-org-server but it is not going to be installed
               Depends: mongodb-org-mongos but it is not going to be installed
               Depends: mongodb-org-tools but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

This similar question recommends running apt-mark showhold to find the held packages and unhold them, but it shows nothing being held.

What's causing this error and how do I fix it?

I'm installing Mongo from Mongo's PPA. And I had previously had PPAs enabled for both the 3.0 and 3.4 versions. I removed the file /etc/apt/sources.list.d/mongodb-org-3.0.list for the 3.0 version, to avoid conflicts, but I think there still might be some lingering issues.

How do you make Ubuntu 16 automatically switch sound output to Bluetooth headphones when they connect?

Currently, my Bluetooth and sound work perfectly, except whenever I want to use my headphones, I have to open settings, go to sound, and select the headset for output. I'd prefer it to work like cell phones do, where if a Bluetooth headset is connected, it automatically switches to that.

This is similar to this old question, but Ubuntu 16 doesn't come with Pulseaudio, nor do I want to screw up my perfectly working Alsa setup by installing it. I did try some of the methods suggested there, and naturally none of them work anymore.

I have "Backup" DejaDup app backing up my home folder to an encrypted external USB hard drive, but it takes hours. The GUI's "backup now" button is grayed out, indicating it's running, and Gnome says "starting scheduled backup". However, I have no idea how long it should take. Is there anyway to get progress info from DejaDup?

Top shows that the duplicity process is running with the option --log-fd=16. Duplicity's manpage indicates that this is the file descriptor of the log file it writes status updates to. However, if I run tail -f 16, I get the error tail: no files remaining. How do I read this log file descriptor?

I have Ubuntu 16 running on a Raspberry Pi 3 mobile platform, and if it's not connected to ethernet, and the wifi's out of range during boot, it takes about 15 minutes to boot, since it appears Ubuntu has a very long timeout while it waits to bring up eth0 or wlan0. I've tested this repeatedly, and when the boot takes forever, I find plugging in an ethernet cable magically makes boot completely instantly.

How do I disable this, so Ubuntu boots up quickly, regardless of network connectivity? I'm using Network Manager, which is excellent at re-establishing a wlan0 connection onces an recognized SSID is detected.

What's the best way to install Ubuntu on a Raspberry Pi 3? I'm finding a few inconsistent links and guides.

I first found this page, and I installed the ubuntu-16.04-preinstalled-server-armhf+raspi3.img.xz image, but I found it to be too unstable to use. On every reboot, it had a 50% chance of encountering a kernel panic. I verified this is a problem in the image, and not my hardware, by re-flashing the same SD card with Raspbian, and successfully booting with that. Unfortunately, the image isn't officially supported, and the lone developer working on it seems to have abandoned any further work and bug fixes.

I also found this page, which implicitly says it supports the Raspberry Pi 3, but the only linked image is to "raspi2". Will this work on the Pi 3?

That page also links here which lists three different ARM images:

• ubuntu-16.04.1-server-arm64.iso
• ubuntu-16.04-preinstalled-server-armhf+raspi2.img.xz
• ubuntu-16.04.1-preinstalled-server-armhf+raspi2.img.xz

I also found this site which offers a Pi 3 image for Ubuntu 16.

Clearly, the last two are just different versions of the same base image, but will the first work on the Pi 3?

Edit: I've confirmed that the images ubuntu-16.04-preinstalled-server-armhf+raspi2.img.xz and ubuntu-16.04.1-preinstalled-server-armhf+raspi2.img.xz do not work with the Pi 3. However, I've confirmed that the image ubuntu-minimal-16.04-server-armhf-raspberry-pi.img.xz works perfectly with the Pi 3.

How do you unpair a bluetooth device from the command line?

I was able to pair my computer with an Android phone via bluetoothctl, but there doesn't seem to be any "unpair" option. Even though I removed the pairing on the phone, running paired-devices still lists it. I've tried running disconnect and remove but they say my device doesn't exist.

Gnome-Terminal is terrible.

It's buggy and whenever Gnome-Shell restarts or resumes from suspend, all Gnome-Terminal windows become unusable and can't be closed. There's an old ticket opened for it, but it'll likely never be fixed.

In the meantime, I've been trying to use other terminal packages. Unfortunately, Gnome-Shell still thinks Gnome-Terminal is what it should use whenever I select "open in terminal" in various menus. If I uninstall Gnome-Terminal, these menus disappear. What's the easiest way to keep the menus, but make my preferred terminal window open instead?

How do you disable the wireless Internet from the command line?

I tried sudo ifconfig eth1 down but network-manager seems to ignore this and keeps trying to reactivate it. What's worse is the network-manager widget doesn't let you disable it either once it starting "trying to connect". Whenever I'm near a spotty connection, it just keeps trying and trying to connect, failing each time and showing an annoying error message, "sorry, we couldn't connect".

How do I disable the keyboard backlight, by turning it completely off, on a Macbook in 12.04?

Whenever I reboot, Ubuntu sets the backlight to 100% brightness, and frustratingly the new function keys no longer support being held down, so I have to press the dim key about 50 times to turn off the backlight.

I recently upgraded from 11.10 to 12.04, and now NetworkManager isn't populating /etc/resolv.conf when connecting to wireless networks, when it had been working perfectly in 11.10. I'm not seeing any explicit errors in either the NetworkManager, UI or in syslog. How do I diagnose what's wrong?

Edit: If I try to run resolvconf, I get the error

resolvconf: Error: /etc/resolv.conf isn't a symlink, not doing anything.

What should it be, a symlink to and/or how do I get NetworkManager to populate it? This says the symlink should point to /run/resolvconf/resolv.conf, but that file does not exist on my system.

Is it possible to allow a keyboard's volume keys to continue working when your desktop is locked? Currently, the default behavior disables all special-function keys until the desktop's unlocked. I like to use my PC as a music player and leave it locked when I'm not directly at the console, but I still want to let people to control the volume if a song's too loud.

I need to configure a machine so software installation can be automated remotely via SSH. Following the wiki, I was able to setup SSH keys so my user can access the machine without a password, but I still need to manually enter my password when I use sudo, which obviously an automated process shouldn't have to do.

Although my /etc/ssh/sshd_config has PermitRootLogin yes, I can't seem to be able to log in as root, presumably because it's not a "real" account with a separate password.

How do I configure SSH keys, so a process can remotely log in as root on Ubuntu?

How do you create a custom application launcher in Gnome Shell?

I have a local Eclipse installation that I'd like to be to quickly launch. So I created a symlink to the eclipse binary and placed it on my desktop. If I open a terminal, cd to ~/Desktop and run ./eclipse it starts Eclipse perfectly. However, if I click the Eclipse icon on my desktop, and choose run, nothing happens.

Alternatively, I wouldn't mind being able to search for Eclipse on the "Activities" screen, but I can't find any documentation on adding or registering custom applications.

Are there any known vulnerabilities to Ubuntu's full disk encryption feature?

I have some storage devices (thumbdrive and a few external hard drives used for backups) that I use with full disk encryption, so that if they're lost or stolen, my data can't be retrieved. Is this a false sense of security?

If someone were to obtain an encrypted drive, would it be possible for them to break the encryption, and if so, how long would it take?

EDIT: To clarify, I'm only asking about non-bootable drives. I'm aware of vulnerabilities to encrypted drives that are still used to boot the OS.

How do you prevent Network Manager from continually prompting for wireless password when it tries to reconnect after the connection temporarily drops?

Unlike this post, this happens for me without suspending. My wireless WPA2 connection might drop a couple times, and NM will automatically reconnect. However, eventually NM will start prompting for the password...which is already filled in. Clicking "Show password" confirms it's already the correct password, and clicking "connect" without changing anything also successfully connects.

Why is it doing this, and how do I stop it? It's driving me crazy. Wicd doesn't do this, but it has a lot of other problems, so I'd rather stick with NM if I could resolve this issue.

I noticed Deja Dup is featured heavily as the default backup tool in Ubuntu 11.10. It looks pretty good, and I noticed elsewhere that it seems to support encryption as well. However, the default version in 11.10 seems to have a slightly different interface and does not appear to list any encryption options. Am I missing something? Why doesn't the 11.10-default version support encryption?

Because of Unity's inability to use any Gnome panel applets, I changed back to the classic gnome panel.

However, even in the classic interface, I'm finding I can't right-click the Gnome panel to change anything.

How do you add applets to the Gnome panel in the classic interface?

Often when I'm working on a terminal, I'll see the "you have new mail in..." message. I know I can see this mail by looking in my system's mail folder (/var/mail/), but this is inconvenient. Also, if the message is important, such as a notice about low system resources, or drive problems, or a failed cron job, I may not see that message or check the system's mail folder for weeks or more.

How can I set it up so that all these messages get sent to a real email service, like Gmail, which I check daily?