Trouble with Java in Ubuntu 20.04 vs 18.04 – Compiling JS code with the Google Closure Library

I have a JavaScript project made with the Google Closure library. It uses Java 8 to compile all the JavaScript into one single JS file.

It works flawlessly on Ubuntu 18.04 and compiles as expected. But when compiling after installing Java 8 in Ubuntu 20.04, it throws the following runtime error:

Uncaught TypeError: a.attachEvent is not a function
at Ic (c.js:33)

One more noticeable test I did: It worked when first installing Java 8 in Ubuntu 18.04, then upgrading to 20.04.

So I wanted to gain more clarity on what sort of differences are there in openjdk-8 when installing them on 18.04 and 20.04?

software installation – How do I run the precompiled sqlite package on Ubuntu 18.04 without installing it?

I downloaded the precompiled sqlite package from the official page

$ ls -l
total 4168
-rwxr-xr-x 1 ubuntu ubuntu  584260 Apr  2 23:40 sqldiff
-rwxr-xr-x 1 ubuntu ubuntu 1162244 Apr  2 23:41 sqlite3
-rwxr-xr-x 1 ubuntu ubuntu 2516704 Apr  2 23:41 sqlite3_analyzer

However, running it this way doesn’t work

-bash: ./sqlite3: No such file or directory

I’m running on a Ubuntu 18.04 box. What do I do?

unity – GNOME Desktop does not appear after upgrading 32 bit system from 16.04 to 18.04

I upgraded my 32 bit system from 16.04 to 18.04. I expected to see the GNOME 3 Desktop. Instead I still see the Unity Desktop. Logging out and back in, there is no desktop selection option presented. I’ve tried installing GNOME 3 manually with no success. I’ve verified that GNOME 3 is installed. There are no desktop options available in the system settings. How can I setup my system to recognize the GNOME 3 Desktop as default and to switch between desktops?

boot – Ubuntu black screen problem problem after upgrading from 18.04 to 20.04

I was upgrading from ubuntu 18.04 to latest stable 20.04 and at the end of the upgradation and clicking (dual boot,another one is windows 10) in to ubuntu my ubuntu got stuck on black screen. I followed and did exactly what was said in temporary soln :
i) adding “nomodeset” in the place of “quiet splash” and then ii)”ctrl+x”
But then I got stuck into this:
enter image description here

Which is saying:

Stopping User Manager for UID 122…

(Ok)Stopped User Manager for UID

Stopping User Runtime Directory /run/user/122…

(Ok)Stopped User Runtime Directory /run/user/122.

(FAILED) Failed to start docker Application Container Engine. See
‘systemctl status docker.service’ for details.

(Ok) Reached trget Multi-User System.

(Ok) Reached target Graphical interface

(Ok) Started Stop Unreadahead data collection 45s after compiled

Starting Update UTMP about System Runlevel Changes…

(Ok) Finished Update UTMP about system runlevel changes

And just keep stuck there. Now what should I do? I should be applying this temp soln and then after login the permanent. How can I disable this docker engine error now?
Thanx in advance for any help.

Ubuntu 18.04 gnuplot has random segmentation faults

I am trying to draw the most basic plot using gnuplot in the terminal and simply entering :

gnuplot> plot 'histogramme.dat' u 1:3

leads to :

gnuplot> Segmentation fault (core dumped)

I can produce image files, but not display on screen, which is highly inconvenient… Would anyone have met the same problem and have a solution, by any chance ?

Have a good day !


ubuntu 18.04 – Openstack: The ext4 file system creation in partition #1 of Virtual disk 1 (vda) failed

I followed the official devstack All-In-One Single Machine installation and after everything installed, when I create an instance with 1GB ram and 10 GB hard disk of ubuntu 18.04 desktop
the messenge show up “The ext4 file system creation in partition #1 of Virtual disk 1 (vda) failed”. My environment is 200 GB hard disk and 10 GB ram with 4 CPU. What is the problem and what should do? Thanks!

Ubuntu 18.04 HDMI problems – Ask Ubuntu

At the start of 2021, I bought two RPi 4 with 4GB of memory for a project. I already own 4 PI (2 OSMC, 1 Samba File Server/Deluge and a Volumio PI. The Volumio never worked. Neither did the HiFiberry sound HAT.

My initial intention was to connect the two Pi4 via an HDMI to DVI converter to 2 different computer monitors.

Brief recap of problems. After buying 3 different micro HDMI to HDMI cables, several DVI/HDMI converters, VGA/HDMI converters, HDMI splitters, new HDMI cables et al I gave up on this project. Nothing ever worked on either monitor, in either PI on any HDMI port. The monitors both work fine on my Intel/ubuntu desktop (DVI to DVI, and HDMI to VGA). Each new converter cable plug etc had to be imported online from China, meaning this failed project took about two months elapsed.

An unfortunate learning experience here is that the micro HDMI ports on the PI are very flimsy, and with all of the plugging/unplugging, both micro HDMI ports on one PI are irreparably damaged and the PI can now only be used headless.

My two modern (2019) SONY TV both have HDMI input so I’ve tried testing with them instead.

I’ve got Raspbian to boot on both PI4, and also on my older PIs.

When booting the Raspbian SD on my older PI3 and Pi2, the desktop GUI started perfectly, automatically filling the whole TV screen. However, on the combination that was my goal (Pi4 to my big TV), it took over 2 whole days of messing with config.txt HDMI parameters to get a full screen (temple) GUI displayed.

This precious SD card of Raspbian will boot on the both Pi4, allow SSH access, and give me a GUI on the PI4 with working micro HDMI ports.

However, according to various Internet sites, my project needs Ubuntu 18.04 32 bit. Raspbian isn’t supported.

I’ve tried creating Ubuntu Core 18.04 using the Raspberry Imager. This will boot, but the password isn’t ubuntu/ubuntu or pi/raspberry so I cannot get access over SSH. The initial PI screen comes up on my TV, disappears after 2 seconds and leaves a black screen. So I have no way of accessing the system. I have noticed that the SD system created by the imager does not contain many of the config files Ubuntu says it needs. I’m surprised it starts at all.

When I create an SD card via download of Ubuntu 18.04.5.. armhf..raspi3 and Etcher, Ubuntu will not boot at all on the headless Pi4. The green ACT light flashes 1 second, and then stays off. The system remains invisible to my router, arp-a and cannot be pinged.

At first I thought it was ubunto didn’t want to boot headless, but the SD card will boot OK on a Pi3 with and without my small TV attached. FWIW Ive tried 3 different SD cards(8Gb, 16GB and 32GB). Same result on all. I also use Raspberry original power supplies, after an APC UPS/Voltage regulator.

As noted earlier, Raspbian will boot on this system however, and I can SSH in. As both micro HDMI ports are broken , clearly no display on the TV.
I have reflashed the EEprom as suggested via the PI imager.

When I try and boot Ubuntu 18.04 on the system with working HDMI, I can SSH in over ubuntu/ubuntu, the TV screen tells me the HDMI port is connected to a raspberry, but also there is NO video signal and the screen remains black except for the title line.

It’s now over 3 months since I started on what I thought would be a five minute job, and am still nowhere near getting a working Ubuntu system (keyboard, mouse, screen) on a PI4.

I suspect what I need to do now is the ubuntu equivalent of editing the Raspbian config.txt to get HDMI video working. Does anybody have any idea of how to achieve this? Either via SSH or by editing a file on the SD card?

I’m running out of ideas now, apart from junking the PI4, buying an Intel nuc and trying to remember what my original project was (for which I’ve written several thousand lines of code)

Below is my Raspbian config.txt file

# For more options and information see
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border

# uncomment to force a console size. By default it will be display's size minus
# overscan.

# uncomment if hdmi display is not detected and composite is being output

# uncomment to force a specific HDMI mode (this will force VGA)

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display

# uncomment for composite PAL

#uncomment to overclock the arm. 700 MHz is the default.

# Uncomment some or all of these to enable the optional hardware interfaces

# Uncomment this to enable infrared communication.

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)

# Enable DRM VC4 V3D driver on top of the dispmanx display stack


18.04 – please help me to install ubuntu18.04 on epson AT997 pc

please help me to install ubuntu18.04 on epson AT997 (when i was try to install ubuntu os on AT997 pc got this error “reboot and select proper boot device or insert boot media in selected boot device and press a key”, even i was set UEFI to disable, security boot to disable )

Ubuntu 18.04 on dual boot PC on starting shows black screen with messages

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18.04 – Is there a problem with my Ubuntu RAID array

I have an Ubuntu 18.08 server with two 1Tb drives in a software RAID1 array, configured during the OS installation process. I wanted the check the health of the array and disks this evening and am not sure if there is a problem with one of my drives.

I see in the ‘mdadm –detail /dev/md0‘ output that one of the drives appears to be removed, and I see from another askubuntu question that the (_U) in the ‘cat /proc/mdstat‘ command output is possibly a signal that a partition has failed.

From the results below, has a drive failed? If so, what is the best course of action? Also, how do I set it so it emails me when a drive fails?

sudo fdisk -l

Disk /dev/loop0: 99.2 MiB, 104030208 bytes, 203184 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop2: 99.2 MiB, 104026112 bytes, 203176 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 310AB5A9-6622-49D9-82C3-B1F2E53DD560

Device       Start        End    Sectors   Size Type
/dev/sda1     2048    2099199    2097152     1G Linux filesystem
/dev/sda2  2099200 1953521663 1951422464 930.5G Linux filesystem

Disk /dev/sdb: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: D634E279-44CC-4ED5-B380-07D02C3C3601

Device       Start        End    Sectors   Size Type
/dev/sdb1     2048       4095       2048     1M BIOS boot
/dev/sdb2     4096    2101247    2097152     1G Linux filesystem
/dev/sdb3  2101248 1953521663 1951420416 930.5G Linux filesystem

Disk /dev/md0: 930.4 GiB, 998991986688 bytes, 1951156224 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


loop0     7:0    0  99.2M  1 loop  /snap/core/10908
loop2     7:2    0  99.2M  1 loop  /snap/core/10859
sda       8:0    0 931.5G  0 disk
├─sda1    8:1    0     1G  0 part
└─sda2    8:2    0 930.5G  0 part
sdb       8:16   0 931.5G  0 disk
├─sdb1    8:17   0     1M  0 part
├─sdb2    8:18   0     1G  0 part  /boot
└─sdb3    8:19   0 930.5G  0 part
  └─md0   9:0    0 930.4G  0 raid1 /

cat /etc/mdadm/mdadm.conf

ARRAY /dev/md0 metadata=1.2 name=ubuntu-server:0 UUID=1d9d79bd:d675f751:144db975:0d24caa9

sudo mdadm –detail /dev/md0

           Version : 1.2
     Creation Time : Fri Aug 30 21:55:50 2019
        Raid Level : raid1
        Array Size : 975578112 (930.38 GiB 998.99 GB)
     Used Dev Size : 975578112 (930.38 GiB 998.99 GB)
      Raid Devices : 2
     Total Devices : 1
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sat Apr  3 23:18:52 2021
             State : clean, degraded
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

              Name : ubuntu-server:0
              UUID : 1d9d79bd:d675f751:144db975:0d24caa9
            Events : 1907228

    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       1       8       19        1      active sync   /dev/sdb3

cat /proc/mdstat

Personalities : (raid1) (linear) (multipath) (raid0) (raid6) (raid5) (raid4) (raid10)
md0 : active raid1 sdb3(1)
      975578112 blocks super 1.2 (2/1) (_U)
      bitmap: 8/8 pages (32KB), 65536KB chunk

unused devices: <none>