Jags's questions

After upgrading to Ubuntu MATE 22.04 Jammy from Ubuntu MATE 21.10 Impish, when I run lsb_release I'm getting this error:

$ lsb_release

bash: /usr/bin/lsb_release: /usr/bin/python3: bad interpreter: No such file or directory

Relevant commands:

$ whereis lsb_release
lsb_release: /usr/bin/lsb_release /usr/share/man/man1/lsb_release.1.gz

$ python -V
bash: python: command not found
$ python3 -V
bash: python3: command not found

$ python3.10 -V
Python 3.10.4

$ which python3 or $ which python
Nothing.

$ which python3.10
/usr/bin/python3.10

$ whereis python
python: /usr/bin/python /usr/share/python /usr/share/man/man1/python.1.gz

$ whereis python3
python3: /usr/lib/python3 /etc/python3 /usr/share/python3 /usr/share/man/man1/python3.1.gz

$ whereis python3.10
python3.10: /usr/bin/python3.10 /usr/lib/python3.10 /etc/python3.10 /usr/local/lib/python3.10 /usr/include/python3.10 /usr/share/man/man1/python3.10.1.gz

ls -lsh /usr/bin/python*
   0 lrwxrwxrwx 1 root root    7 Oct 11  2021 /usr/bin/python -> python3
   0 lrwxrwxrwx 1 root root    9 Jul 28  2021 /usr/bin/python2 -> python2.7
3.5M -rwxr-xr-x 1 root root 3.5M Mar 12 11:54 /usr/bin/python2.7
5.7M -rwxr-xr-x 1 root root 5.7M Apr  2 14:34 /usr/bin/python3.10
   0 lrwxrwxrwx 1 root root   34 Apr  2 14:34 /usr/bin/python3.10-config -> x86_64-linux-gnu-python3.10-config
   0 lrwxrwxrwx 1 root root   17 Mar 25 18:11 /usr/bin/python3-config -> python3.10-config
4.0K -rwxr-xr-x 1 root root 1.8K Aug  6  2019 /usr/bin/python3-unidiff

$ sudo ln -s /usr/bin/python3 /usr/bin/python3.10
ln: failed to create symbolic link '/usr/bin/python3.10': File exists

$ sudo update-alternatives --config python3
update-alternatives: error: no alternatives for python3

$ sudo update-alternatives --config python
update-alternatives: error: no alternatives for python

The way I found out about lsb_release error is because mate-menu (Advanced MATE Menu) stopped working (disappeared from taskbar), and when I tried to reinstall it (using Synaptic), I got this error:

E: mate-menu: package is in a very bad inconsistent state; you should  reinstall it before attempting configuration

Can't exec "lsb_release": No such file or directory at /usr/share/perl5/Debconf/FrontEnd/Gnome.pm line 184, <> line 1.
Use of uninitialized value in lc at /usr/share/perl5/Debconf/FrontEnd/Gnome.pm line 184, <> line 1.
(Reading database ... 378043 files and directories currently installed.)

Preparing to unpack .../lsb-release_11.1.0ubuntu4_all.deb ...
Unpacking lsb-release (11.1.0ubuntu4) over (11.1.0ubuntu4) ...
dpkg: error processing package mate-menu (--configure):

 package is in a very bad inconsistent state; you should
 reinstall it before attempting configuration

Setting up lsb-release (11.1.0ubuntu4) ...
Processing triggers for man-db (2.10.2-1) ...
Errors were encountered while processing:
 mate-menu

Though I have found these similar threads, they are not working out for me. Thank you.

https://askubuntu.com/a/919416/928088

https://stackoverflow.com/q/62329393/11855487

I like to write a Bash script to generate sha256sum hash of a file, and save its output with hash and only filename.extension, excluding the path.

I'm not getting the output I want with both of the following scripts I have tried so far:

Note: There will be a new file with a new name every time the script is run, hence I'm using *.iso in the script.

(1)

#!/bin/bash

cd /home/admn/Downloads

find -maxdepth 1 -type f -name "*.iso" -exec bash -c "sha256sum '{}' > '{}'.sha256" \;

exit;

This creates a file Test.iso.sha256 but with an output: e64d11052abf5c3e19f0cd60e0b9c6196d8cb8615eba415ef1a3ac746f4b0c29 ./Test.iso

While I just want Test.iso without ./

(2)

#!/bin/bash

cd /home/admn/Downloads

fullfilename="/home/admn/Downloads/*.iso"
filename=$(basename "$fullfilename")

sha256sum $filename > "$filename".sha256

exit;

This does generate the output I want: e64d11052abf5c3e19f0cd60e0b9c6196d8cb8615eba415ef1a3ac746f4b0c29 Test.iso but the file it creates have * in it instead of name: *.iso.sha256. Thanks.

OS: Ubuntu MATE 21.10

Bash: Version 5.1.8(1)-release (x86_64-pc-linux-gnu)

Is there a key combination to enter and exit fullscreen view in virt-manager, while a virtual machine is running, and its window open?

Obviously I can enter or exit using mouse:

To enter: Click View > Fullscreen

To exit: Hover mouse at the top-center, and click Leave fullscreen icon.

I have tried key combinations from this AskUbuntu thread: How do I unmaximize full screen view in virt-manager? but they are not working in Ubuntu MATE 21.04. Many thanks.

OS: Ubuntu MATE 21.04

virt-manager: 1:3.2.0-3

Note: Though there's an answer from jeff-schaller, it depends on zsh; so I would like to get an answer based on Bash.

I like to create a Bash script to conditionally delete older files from a backup directory.

There are 2 conditions for 2 distinct file backups:

1, Keep the latest copy of Edge_Profile_*.tgz, and delete rest of Edge_Profile_*.tgz only if they are older than 5 days.

2, Keep the latest copy of Firefox_Profile_*.tgz, and delete rest of Firefox_Profile_*.tgz, doesn't matter how old are they.

Here's how I have modify this AskUbuntu answer: https://askubuntu.com/a/933098/928088

Script:

#!/bin/bash

LOG_FILE="/home/admn/Cleanup.log"
TEMP_LOG="/tmp/Temp_Cleanup.log"

mv $LOG_FILE $TEMP_LOG

{

cd /home/admn/Downloads/Test;

echo "Cleanup log:" `date`

find /home/admn/Downloads/Test/Edge_Profile_*.tgz -type f \( -mtime +5 -printf 'Y\t' -o -printf 'N\t' \) -printf '%A@\t%p\0' |
    sort -zk2,2 | head -zn -1 | while read -r -d '' flag _ file; do \
        case "$flag" in 
            'Y') echo rm "$file" 
               ;; 
            *) echo "skipping $file (too new)"
               ;; 
        esac;
done

echo

find /home/admn/Downloads/Test/Firefox_Profile_*.tgz -type f \( -printf 'Y\t' -o -printf 'N\t' \) -printf '%A@\t%p\0' |
    sort -zk2,2 | head -zn -1 | while read -r -d '' flag _ file; do \
        case "$flag" in 
            'Y') echo rm "$file" 
               ;; 
            *) echo "skipping $file (too new)"
               ;; 
        esac        
done

} &>> $LOG_FILE

cat $TEMP_LOG >>$LOG_FILE

exit;

Output in the logfile with echo:

/usr/local/scripts/cleanup.sh

rm /home/admn/Downloads/Test/Edge_Profile_Jul_06_2021_00-35.tgz
rm /home/admn/Downloads/Test/Edge_Profile_Jul_07_2021_00-35.tgz
....
skipping /home/admn/Downloads/Test/Edge_Profile_Jul_12_2021_00-35.tgz (too new)
skipping /home/admn/Downloads/Test/Edge_Profile_Jul_13_2021_00-35.tgz (too new)
....

rm /home/admn/Downloads/Test/Firefox_Profile_Jul_01_2021_00-35.tgz
rm /home/admn/Downloads/Test/Firefox_Profile_Jul_02_2021_00-35.tgz
....

Output in the logfile while actually running the script, without echo:

/home/admn/Downloads/cleanup.sh: line 24: skipping /home/admn/Downloads/Test/Edge_Profile_Jul_12_2021_00-35.tgz (too new): No such file or directory
/home/admn/Downloads/cleanup.sh: line 24: skipping /home/admn/Downloads/Test/Edge_Profile_Jul_13_2021_00-35.tgz (too new): No such file or directory
....

Total files in the directory: 20 files

1, Edge_Profile_*.tgz: From July 06 to July 17: 12 files

2, Firefox_Profile_*.tgz: From July 01 to July 08: 8 files

The issues:

(1) I think the script is kind of working but I'm not sure as I've modified most part without knowing what's going on.

(2) Output to logfile:

I would prefer the exact same output in the logfile that I get with echo, except just the filenames (not with full path), like:

rm Edge_Profile_Jul_11_2021_00-35.tgz

skipping Edge_Profile_Jul_12_2021_00-35.tgz (too new)

OS: Ubuntu MATE 21.04

Thanks a lot.

Edit: Since macvtap is not working for communication between host and guest, I tried to used a bridge, but then there's no internet on the host and ping or ssh still doesn't work.

This is how I've created a bridge:

nmcli connection add type bridge ifname br0

Output:
Connection 'bridge-br0' (bf1406b0-4ea8-4338-9edc-0f58fd019bec) successfully added.


nmcli con add type ethernet con-name br-slave-1 ifname enp0s25 master br0

nmcli con add type ethernet con-name br-slave-1 ifname enp0s25 master br0

nmcli con modify bridge-br0 bridge.stp no

nmcli connection add type ethernet ifname  bridge-br0  ipv4.method auto

Output:
Connection 'ethernet-bridge-br0' (6c2c5495-6e43-4cd5-a574-014042987781) successfully added.


After reboot:

nmcli con show

NAME                       UUID                                  TYPE      DEVICE  
bridge-br0                 bf1406b0-4ea8-4338-9edc-0f58fd019bec  bridge    br0     
br-slave-1                 a998c09f-5f46-4586-b654-cdfa6a21dca5  ethernet  enp0s25 
ethernet-bridge-br0        6c2c5495-6e43-4cd5-a574-014042987781  ethernet  --      
Wired connection 1         8559f62b-0cb9-3935-ba65-b6d57c0043c8  ethernet  --      

Now if I disconnect br-slave-1:

nmcli con down br-slave-1

I get the internet back on the host but then there's no internet on guest and ping still wouldn't work:

So is there a way to use ssh between host and guest while using qemu with kvm, using nmcli or NetworkManager GUI? Many thanks.

Note: As I need to use few different wireless networks on and off, I like to stay away from netplan or network interfaces, hence I'm trying to setup bridge either using nmcli or NetworkManager GUI.

Original post:

I'm trying to SSH into a guest from the host. Both host and guest machines are Ubuntu MATE 21.04.

Internet works just fine both from host and guest machines.

IP addresses:

(1) Router: Asus RT AC68U > 192.168.1.1
(2) Host: Ubuntu MATE 21.04 > 192.168.1.106
(3) Guest: Ubuntu MATE 21.04 > 192.168.1.139

Firewall have been disabled/stopped on all three:

(1) Router: Asus RT AC68U > SPI Firewall > Disabled
(2) Host: Ubuntu MATE 21.04 > sudo systemctl stop nftables
(3) Guest: Ubuntu MATE 21.04 > sudo systemctl stop nftables

When I try to ssh-copy-id, I get this error: No route to host

ssh-copy-id [email protected]
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/usr/bin/ssh-copy-id: ERROR: ssh: connect to host 192.168.1.139 port 22: No route to host

So I tried to ping (does not work either way; "host to guest" or "guest to host"):

ping 192.168.1.139

PING 192.168.1.139 (192.168.1.139) 56(84) bytes of data.
From 192.168.1.106 icmp_seq=1 Destination Host Unreachable
From 192.168.1.106 icmp_seq=2 Destination Host Unreachable

However ping does work from either "host to router" or "guest to router":

ping from host to router:

ping 192.168.1.1

PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.400 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.339 ms

ping from guest to router:

ping 192.168.1.1

PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.651 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.625 ms

Host and guest machines are connected through a network bridge br0, which I've created using Netwrok Manager GUI. Bridge br0 have two "bridged connections", br0 slave 1 and br0 slave 2.

Enable STP (spanning Tree Protocol is "unchecked". Though it did not make any difference even I "checked" it.

Additional details which I think would be helpful:

sudo nano /etc/libvirt/qemu/networks/host-bridge.xml

<network>
  <name>host-bridge</name>
  <uuid>0ae7be62-9f9e-4346-9309-88985dd0f5ad</uuid>
  <forward mode='bridge'/>
  <bridge name='br0'/>
</network>


virsh net-list --all

 Name          State    Autostart   Persistent
------------------------------------------------
 host-bridge   active   yes         yes

Results of ip a and ip r on the host machine:

ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: enp0s25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether e0:69:95:4d:7c:9c brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.106/24 brd 192.168.1.255 scope global dynamic noprefixroute enp0s25
       valid_lft 599784sec preferred_lft 599784sec
    inet 192.168.1.104/24 brd 192.168.1.255 scope global secondary noprefixroute enp0s25
       valid_lft forever preferred_lft forever
3: wlxd0374547816a: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether d0:37:45:47:81:6a brd ff:ff:ff:ff:ff:ff
4: br0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 96:d5:ab:3c:a7:e8 brd ff:ff:ff:ff:ff:ff
7: macvtap2@enp0s25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 500
    link/ether 52:54:00:1f:6a:cd brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.140/24 brd 192.168.1.255 scope global noprefixroute macvtap2
       valid_lft forever preferred_lft forever

ip r       

default via 192.168.1.1 dev enp0s25 proto dhcp src 192.168.1.104 metric 202 
default via 192.168.1.1 dev macvtap2 proto dhcp src 192.168.1.140 metric 207 
169.254.0.0/16 dev macvtap2 scope link metric 1000 
192.168.1.0/24 dev enp0s25 proto dhcp scope link src 192.168.1.104 metric 202 
192.168.1.0/24 dev macvtap2 proto dhcp scope link src 192.168.1.140 metric 207 

Results of ip a and ip r on the guest machine:

ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 52:54:00:1f:6a:cd brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.139/24 brd 192.168.1.255 scope global dynamic noprefixroute enp2s0
       valid_lft 603989sec preferred_lft 603989sec
    inet6 fe80::d316:3db7:9af5:8d0c/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

ip r

default via 192.168.1.1 dev enp2s0 proto dhcp metric 100 
169.254.0.0/16 dev enp2s0 scope link metric 1000 
192.168.1.0/24 dev enp2s0 proto kernel scope link src 192.168.1.139 metric 100 

NIC details (from Virtual machine manager) of the guest machine:

Virtual Network Interface:

Network source: Macvtap device
Device name: enp0s25
Device model: virtio

XML:
<interface type="direct">
  <mac address="52:54:00:1f:6a:cd"/>
  <source dev="enp0s25" mode="bridge"/>
  <target dev="macvtap2"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x02" slot="0x00" function="0x0"/>
</interface>

OS: Ubuntu MATE 21.04

qemu: 1:5.2+dfsg-9ubuntu3

bridge-utils: 1.6-5ubuntu1

virt-manager: 1:3.2.0-3

libvirt-daemon: 7.0.0-2ubuntu2

Thanks alot in advance.

Edit-1:

brctl show br0

bridge name bridge id       STP enabled interfaces
br0     8000.96d5ab3ca7e8   no      

Though I have gone through quite a few threads on AskUbuntu, I couldn't find a proper way to disable these Evolution services, especially when Evolution is purged from the system already, in Ubuntu MATE 21.04.

These services are not listed under systemctl list-unit-files --type=service, so I can't use sudo systemctl mask.

ps -ef | grep evolution

admn 1973 1459 0 17:15 ? 00:00:00 /usr/libexec/evolution-source-registry
admn 2023 1459 0 17:15 ? 00:00:00 /usr/libexec/evolution-calendar-factory
admn 2058 1459 0 17:15 ? 00:00:00 /usr/libexec/evolution-addressbook-factory

These 2 Evolution related packages are still there, because purging them would remove a lot of other packages.

evolution-data-server
evolution-data-server-common

Result of ls -lsh /usr/libexec/evolution*:

$ ls -lsh /usr/libexec/evolution*

 16K -rwxr-xr-x 1 root root  15K Jun 22 20:57 /usr/libexec/evolution-addressbook-factory
 48K -rwxr-xr-x 1 root root  47K Jun 22 20:57 /usr/libexec/evolution-addressbook-factory-subprocess
116K -rwxr-xr-x 1 root root 115K Jun 22 20:57 /usr/libexec/evolution-calendar-factory
136K -rwxr-xr-x 1 root root 135K Jun 22 20:57 /usr/libexec/evolution-calendar-factory-subprocess
 60K -rwxr-xr-x 1 root root  59K Jun 22 20:57 /usr/libexec/evolution-scan-gconf-tree-xml
124K -rwxr-xr-x 1 root root 123K Jun 22 20:57 /usr/libexec/evolution-source-registry
 20K -rwxr-xr-x 1 root root  19K Jun 22 20:57 /usr/libexec/evolution-user-prompter

/usr/libexec/evolution-data-server:
total 116K

 32K -rwxr-xr-x 1 root root  31K Jun 22 20:57 addressbook-export
8.0K -rwxr-xr-x 1 root root 7.0K Jun 22 20:57 csv2vcard
 52K -rwxr-xr-x 1 root root  51K Jun 22 20:57 evolution-alarm-notify
 24K -rwxr-xr-x 1 root root  23K Jun 22 20:57 list-sources

OS: Ubuntu MATE 21.04

evolution-data-server: 3.40.0-1ubuntu1.1

evolution-data-server-common: 3.40.0-1ubuntu1.1

Thanks a lot in advance.

I like to define a function in ~/.bashrc and use it in different scripts either via export -f or source .bashrc.

The function:

nano ~/.bashrc

function test_func() {
    yt-dlp -f '299+140' --merge-output-format mp4 -cia List.txt;
}

export -f test_func

The script:

#!/bin/bash

cd /home/admn/Downloads/YT_DL;

test_func --autonumber-start 101 -o '%(autonumber)1d_%(title)s.%(ext)s';

Problem-1:

After test_func, rest of the command --autonumber-start 101 -o '%(autonumber)1d_%(title)s.%(ext)s' is not working at all.

Problem-2:

Earlier when I tried to use source .bashrc in my script, I was getting these errors:

/usr/local/scripts/test.sh: line 3: .bashrc: No such file or directory
/usr/local/scripts/test.sh: line 12: test_func: command not found

The function (without export -f):

nano ~/.bashrc

function test_func() {
    yt-dlp -f '299+140' --merge-output-format mp4 -cia List.txt;
}

The script (with source .bashrc):

#!/bin/bash

source .bashrc

cd /home/admn/Downloads/YT_DL;

test_func --autonumber-start 101 -o '%(autonumber)1d_%(title)s.%(ext)s';

Edit-1:

$ bash -xv /usr/local/scripts/test.sh
#!/bin/bash

source /home/admn/.bashrc
+ source /home/admn/.bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# alias pip='pip3.7'
alias python='python3'
++ alias python=python3

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac
++ case $- in
++ return

test_func --autonumber-start 101 -o '%(autonumber)1d_%(title)s.%(ext)s';
+ test_func --autonumber-start 101 -o '%(autonumber)1d_%(title)s.%(ext)s'
/usr/local/scripts/test.sh: line 5: test_func: command not found
$ 

These are some of the threads I have gone through; and though I've got some ideas, I still couldn't work out a solution for my use case. Thanks.

https://unix.stackexchange.com/questions/63665/how-to-define-a-bash-function-that-can-be-used-by-different-scripts

https://stackoverflow.com/questions/6218268/how-to-define-a-bash-function-for-use-in-any-script

https://stackoverflow.com/questions/17219174/variables-set-in-bashrc-and-accessing-them-in-shellscript

https://stackoverflow.com/questions/1500499/how-do-you-call-a-function-defined-in-bashrc-from-the-shell

Define a globally available bash function to be used by any script

OS: Ubuntu MATE 21.04

Bash: 5.1.4(1)-release (x86_64-pc-linux-gnu)

I'm trying to find keyboard shortcuts to:

(1) Show notifications list

(2) Clear notifications list

I have gone through this AskUbuntu thread:

https://askubuntu.com/questions/1325785/create-a-custom-keyboard-key-for-opening-the-latest-notification

and Ubuntu desktop guide:

https://help.ubuntu.com/stable/ubuntu-help/shell-notifications.html.en

but none of 'em working for Ubuntu MATE 21.04... because when I open the Menu > Keyboard Shortcuts, there are no entries for anything related to notifications. Also, Super+V or Super+N does nothing.

I can't find any option to view or create keyboard shortcuts in Ayatana indicators settings either.

So, how do I create custom keyboard shortcuts to show and clear notifications list? Thanks.

OS: Ubuntu MATE 21.04

Indicator applet complete: 1.24.0

Ayatana indicators settings: 21.1.28-1

Ayatana indicator notifications: 0.8.90-1

I would like to preserve colors, in console, of a Bash script output, while logging and echo it to console.

When I run a script with the following code, I lose colors in console.

LOG_FILE="Merge.log"
touch $LOG_FILE

exec > >(tee $LOG_FILE) 2>&1;

Here are screenshots to make it clear:

Screen one and two are with logging disabled (commented out) in the script:

Screen-1:

Screen-2:

Screen three and four are with logging enabled in the script:

Screen-3:

Screen-4:

I have searched quite a lot but couldn't find any solution. Thanks.

OS: Ubuntu MATE 21.04

Bash version: 5.1.4(1)-release (x86_64-pc-linux-gnu)

I like to create a Bash script to concatenate MP4 files using FFmpeg, in batches of 5 files at a time for a directory with 100 MP4 files, so that afterwards there would be 20 files like:

001_005.mp4, 006_010.mp4, and so on...

instead of just 1 file consisting of all 100 files.

Contents of mylist.txt:

file 001.mp4
file 002.mp4
file 003.mp4
file 004.mp4
file 005.mp4
............
file 099.mp4
file 100.mp4

Though I've found a command that works just fine (from this StackOverflow thread), it would create only 1 file consisting all 100 files.

#!/bin/bash

cd /home/admn/Downloads/MP4_Files;

# Create mylist.txt:
for f in *.mp4
do
    echo "file $f" >> mylist.txt
done;

# Concatenate files:
ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4;

So, how do I modify the ffmpeg command so that it concat in batches of 5 files at a time.

All the files have exact same resolution (1080p), audio, and video codecs.

OS: Ubuntu MATE 21.04

ffmpeg version: 4.3.2-0+deb11u1ubuntu1

I just noticed that, there are alot of Debian keyring GPG files inside /usr/share/keyrings/ directory of my Ubuntu MATE 21.04 installation (which have been upgraded from previous versions regularly).

$ ls -lsh /usr/share/keyrings/
total 32M
 12K -rw-r--r-- 1 root root 8.5K Mar 26 16:41 debian-archive-bullseye-automatic.gpg
 12K -rw-r--r-- 1 root root 8.6K Mar 26 16:41 debian-archive-bullseye-security-automatic.gpg
4.0K -rw-r--r-- 1 root root 2.4K Mar 26 16:41 debian-archive-bullseye-stable.gpg
8.0K -rw-r--r-- 1 root root 8.0K Mar 26 16:41 debian-archive-buster-automatic.gpg
8.0K -rw-r--r-- 1 root root 8.0K Mar 26 16:41 debian-archive-buster-security-automatic.gpg
4.0K -rw-r--r-- 1 root root 2.3K Mar 26 16:41 debian-archive-buster-stable.gpg
 56K -rw-r--r-- 1 root root  55K Mar 26 16:41 debian-archive-keyring.gpg
 40K -rw-r--r-- 1 root root  37K Mar 26 16:41 debian-archive-removed-keys.gpg
8.0K -rw-r--r-- 1 root root 7.3K Mar 26 16:41 debian-archive-stretch-automatic.gpg
8.0K -rw-r--r-- 1 root root 7.3K Mar 26 16:41 debian-archive-stretch-security-automatic.gpg
4.0K -rw-r--r-- 1 root root 2.3K Mar 26 16:41 debian-archive-stretch-stable.gpg
 28M -rw-r--r-- 1 root root  28M Mar 25 02:40 debian-keyring.gpg
2.6M -rw-r--r-- 1 root root 2.6M Mar 25 02:40 debian-maintainers.gpg
772K -rw-r--r-- 1 root root 771K Mar 25 02:40 debian-nonupload.gpg
 28K -rw-r--r-- 1 root root  26K Mar 25 02:40 debian-role-keys.gpg

4.0K -rw-r--r-- 1 root root 2.3K May 11 15:49 ubuntu-advantage-cis.gpg
4.0K -rw-r--r-- 1 root root 2.2K May 11 15:49 ubuntu-advantage-esm-apps.gpg
4.0K -rw-r--r-- 1 root root 2.3K May 11 15:49 ubuntu-advantage-esm-infra-trusty.gpg
4.0K -rw-r--r-- 1 root root 2.3K May 11 15:49 ubuntu-advantage-fips.gpg
8.0K -rw-r--r-- 1 root root 7.3K Sep 18  2018 ubuntu-archive-keyring.gpg
8.0K -rw-r--r-- 1 root root 6.6K Oct 27  2016 ubuntu-archive-removed-keys.gpg
4.0K -rw-r--r-- 1 root root 3.0K Mar 27 05:04 ubuntu-cloudimage-keyring.gpg
   0 -rw-r--r-- 1 root root    0 Jan 17  2018 ubuntu-cloudimage-removed-keys.gpg
4.0K -rw-r--r-- 1 root root 1.2K May 27  2010 ubuntu-master-keyring.gpg
$

When I compared this with a fresh, virtual installation of Ubuntu MATE 21.04, it only had Ubuntu keyring files.

So, is it safe to remove those Debian keyring files? Thanks.

Edit-1:

dpkg -S /usr/share/keyrings/debian-* | awk -F: '{print $1}' | sort -u

debian-archive-keyring
debian-keyring

aptitude why debian-archive-keyring

i   packaging-dev    Recommends ubuntu-dev-tools      
i A ubuntu-dev-tools Recommends debian-archive-keyring

aptitude why debian-keyring

i   packaging-dev    Recommends ubuntu-dev-tools
i A ubuntu-dev-tools Recommends debian-keyring  

I have gone through quite a few threads on AskUbuntu and elsewhere but as it sounds, all of them are about deleting hidden files, while I'm trying to:

delete non-hidden files, from a non-hidden directory, which is inside a hidden directory.

I like to delete all files inside /home/admn/.cache/thumbnails/normal/ directory using a Bash script.

The simple script that I have created:

sudo nano /usr/local/scripts/test.sh

#!/bin/bash

shopt -s dotglob

rm '/home/admn/.cache/thumbnails/normal/*'

shopt -u dotglob

Note: As suggested, I've tried using double-quotes " in the script, but still getting the same error.

sudo chmod +x /usr/local/scripts/test.sh

The error I'm getting:

rm: cannot remove '/home/admn/.cache/thumbnails/normal/*': No such file or directory

Thanks.

How do I create a CSV file from a TXT file as per the following example? Thanks.

TXT file:
This is line number one
This is line number two with extra words
This is line number three with even more words

Resulting CSV file:
Col#1 Col#2 Col#3 Col#4  Col#5 Col#6 Col#7 Col#8 Col#9
This  is    line  number one
This  is    line  number two   with  extra words
This  is    line  number three with  even  more  words

Edit: Well, my question is different from and hence not a duplicate of:

https://askubuntu.com/questions/1214146/trying-to-create-a-csv-file-from-a-text-file-in-ubuntu

because the other question is asking to "organize" each line in to "columns", while my question is about organizing each word (separated by whitespaces) into a new column. Thanks.

I'm trying to setup a cron job to archive/backup /home/username/.mozilla/ directory and all its sub-directories, including hidden files, using tar. I like to run the job at 12:01 AM every night.

Here's what I have planned so far:

crontab -e

1 0 * * * tar -zcf /home/username/Dropbox/Backups/Firefox_Profile_$(date +%b_%d_%Y_"%H-%M").tgz home/username/.mozilla/ && echo "Firefox profile backed up on:" `date` >> /home/username/jobs

Though I have not actually setup the cron job yet, when I run this command in terminal:

tar -zcf /home/username/Dropbox/Backups/Firefox_Profile_$(date +%b_%d_%Y_"%H-%M").tgz home/username/.mozilla/

it does create a compressed archive, but upon exctraction, it creates a directory home > username > .mozilla and its sub-directories.

What I am looking for is:

(1) upon extraction there would be either .mozilla or preferably mozilla (removing the dot), and its sub-directories, including hidden files (no home or username directories).

(2) is tar -zcf the best way to get maximum compression.

(3) keep all the file permissions as it is.

(4) do I need to have [user] (which is "username") in this command: 1 0 * * * username tar -zcf

Thanks a lot.

I have installed Realtek RTL88x2BU drivers from Cilynx's GitHub repo using DKMS installation in Ubuntu MATE 19.04 with kernel 5.3.4 (and later 5.3.7)

Drivers worked fine for a week, then suddenly stopped detecting TP-Link Archer T3U AC1300 Wireless USB Adapter altogether. The same adapter works fine with other PC.

This is how drivers were installed:

cd rtl88x2bu
VER=$(sed -n 's/\PACKAGE_VERSION="\(.*\)"/\1/p' dkms.conf)
sudo rsync -rvhP ./ /usr/src/rtl88x2bu-${VER}
sudo dkms add -m rtl88x2bu -v ${VER}
sudo dkms build -m rtl88x2bu -v ${VER}
sudo dkms install -m rtl88x2bu -v ${VER}
sudo modprobe 88x2bu

So how could I completely remove kernel modules of all the previous versions (1.1, 5.6.1, etc) for RTL88x2BU? Many thanks.

Though I have gone through quite a few threads on AskUbuntu (1, 2, 3), and elsewhere, I'm little confuse on how to proceed.

I'd like to completely remove ufw, delete all iptables chains and rules, for a fresh start with nftables firewall in Ubuntu MATE 19.04

If I understand correctly (from the threads I have linked), I need to run the following:

sudo systemctl reset ufw

sudo systemctl disable ufw

sudo apt purge ufw gufw

sudo iptables -F

sudo iptables -Z

Then ?

for i in `iptables -L INPUT --line-numbers |grep '[0-9].*ufw' | cut -f 1 -d ' ' | sort -r `; do iptables -D INPUT $i ; done
for i in `iptables -L FORWARD --line-numbers |grep '[0-9].*ufw' | cut -f 1 -d ' ' | sort -r `; do iptables -D FORWARD $i ; done
for i in `iptables -L OUTPUT --line-numbers |grep '[0-9].*ufw' | cut -f 1 -d ' ' | sort -r `; do iptables -D OUTPUT $i ; done
for i in `iptables -L | grep 'Chain .*ufw' | cut -d ' ' -f 2`; do iptables -X $i ; done

The questions I have are:

(1) How do I "disable or deactivate" iptables so it doesn't interfere with Nftables firewall later on.

(2) In addition to removing ufw, should I remove iptables too:

sudo apt remove --auto-remove iptables

(3) Then proceed with installing and configuring nftables, is this the correct order?

Every time Vivaldi gets updated, I have to run this sed command to apply custom.css

sudo sed -i '1s/^/@import "custom.css";/' /opt/vivaldi-snapshot/resources/vivaldi/style/common.css

Now the command works fine in the terminal but not when I try to run it by creating an alias in ~/.bash_aliases or even through a bash script (placed inside /bin/ with executable permission). I did try using full-path for "custom.css" but it still didn't work. Thanks.

Edit:

(1) Through alias:

alias vivupdate="sed -i '1s/^/@import "custom.css";/' /opt/vivaldi-snapshot/resources/vivaldi/style/common.css"

When I tried to run, I'm getting this error:

$ sudo vivupdate
[sudo] password for admn:

sudo: vivupdate: command not found
$ 

(2) Through a Bash script:

#!/bin/bash
sed -i '1s/^/@import "custom.css";/' /opt/vivaldi-snapshot/resources/vivaldi/style/common.css

created vivupdate.sh, made it executable and placed it inside /bin/.

Then edited sudoers file and added:

user ALL=(ALL:ALL) NOPASSWD:/bin/vivupdate.sh

But when I run the script in terminal, I get this error:

sed: couldn't open temporary file /opt/vivaldi-snapshot/resources/vivaldi/style/sedCIt48u: Permission denied

I'd like to create a simple alias:

alias gate=route | grep default | awk '{print $2}'

and even though the command does work in terminal, it's not working through ~/.bash_aliases. Thanks.

I have gone through quite a few setup guides but couldn't figure out, how to configure VSFTPD for LAN-only access, and restrict the access to a single directory (e.g.: ~/Downloads).

If possible, I do not even want to expose its presence to the Internet. Any help is greatly appreciated.

PC: Ubuntu Mate 19.04 64-bit.

So while trying to solve Logitech TouchPad T650 intermittent freezing issue, I installed Solaar ( https://pwr.github.io/Solaar/ ) via Synaptic. During the installation, it asked me to select between GDM3 and LightDM and I accidentally selected GDM3.

So now I'm stuck with GDM3 (to me it feels like being blinded). So far I've tried the following few times and rebooted few times but to no avail. The command runs just find but after reboot, it just goes back to GDM3.

sudo dpkg-reconfigure lightdm

And on top of this TouchPad has kinda stopped working... while cursor moves, left/right click is not working. It's a desktop PC running Ubuntu Mate 18.10 64bit.

I like to get back to LightDM and remove Solaar, GDM3, etc.. completely. Thanks alot in advance.