When loading your wordpress page, you see the following message:
Your PHP installation appears to be missing the MySQL extension which is required by WordPress.
Install the php[VERSION]-mysql package for the PHP version that is running wordpress.
For example:
sudo apt -y install php8.1-mysql
This is an example of using a Here document (Heredoc) in bash to write an inline string to a file.
cat <<EOF >/etc/dhcp/dhcpd.conf
authoritative;
default-lease-time 86400;
max-lease-time 86400;
subnet 192.168.99.0 netmask 255.255.255.0 {
range 192.168.99.100 192.168.99.150;
option routers 192.168.99.1;
option domain-name-servers 192.168.99.1;
option domain-name "local";
}
EOF
When running apt update, you see the following error message:
Err:13 https://download.virtualbox.org/virtualbox/debian jammy InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A2F683C52980AECF
This error occurs due to the VirtualBox repo using the outdated (as of April 2022) apt-key method of importing keys.
You can import the key by just installing the tailscale repo again (these commands are based on the commands from the VirtualBox Linux downloads page):
wget -qO- https://www.virtualbox.org/download/oracle_vbox_2016.asc | sudo gpg --dearmor --yes --output /usr/share/keyrings/oracle-virtualbox-2016.gpg echo "deb [arch=amd64 signed-by=/usr/share/keyrings/oracle-virtualbox-2016.gpg] https://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib" | sudo tee /etc/apt/sources.list.d/virtualbox.list
and then running
apt update
again.
When running apt update, you see the following error message:
Err:27 https://pkgs.tailscale.com/stable/ubuntu jammy InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 458CA832957F5868
This error occurs due to the Tailscale repo using the outdated (as of April 2022) apt-key method of importing keys.
You can import the key by just installing the tailscale repo again (these commands are listed on the official tailscale installation page):
curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/jammy.noarmor.gpg | sudo tee /usr/share/keyrings/tailscale-archive-keyring.gpg >/dev/null curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/jammy.tailscale-keyring.list | sudo tee /etc/apt/sources.list.d/tailscale.list
and then running
apt update
again.
This script will generate a random password stored in a JSON file:
echo "{\"secret\": \"$(pwgen 30 1)\"}" > secret.json{"secret": "thie2uv6Ro3cah2oodohx2vai5Ahka"}
You can simply view /proc/mdstat:
cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4] [linear] [multipath] [raid0] [raid10]
md2 : active raid5 sdb3[4] sdd3[0] sda3[2] sdc3[1]
2111434752 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_]
[===>.................] recovery = 16.2% (114244316/703811584) finish=48.8min speed=201053K/sec
bitmap: 2/6 pages [8KB], 65536KB chunk
md1 : active raid1 sdb2[3] sda2[2] sdd2[0] sdc2[1]
1046528 blocks super 1.2 [4/4] [UUUU]
md3 : active raid5 sdb4[4] sda4[2] sdd4[0] sdc4[1]
44661594624 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_]
resync=DELAYED
bitmap: 2/111 pages [8KB], 65536KB chunk
md0 : active raid1 sda1[2] sdb1[3] sdd1[0] sdc1[1]
33520640 blocks super 1.2 [4/4] [UUUU]
unused devices: <none>
When running apt update, you see the following error message:
Err:14 https://repo.skype.com/deb stable InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1F3045A5DF7587C3
This error occurs due to the Skype repo using the outdated (as of April 2022) apt-key method of importing keys.
You can import the key using the following commands:
wget -qO- https://repo.skype.com/data/SKYPE-GPG-KEY | gpg --dearmor | sudo tee /usr/share/keyrings/skype-archive-keyring.gpg echo "deb [signed-by=/usr/share/keyrings/skype-archive-keyring.gpg] https://repo.skype.com/deb stable main" > /etc/apt/sources.list.d/skype-stable.list
and then running
apt update
again.
When running apt update, you see the following error message:
Err:2 https://linux.teamviewer.com/deb stable InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C5E224500C1289C0
This error occurs due to the teamviewer repo using the outdated (as of April 2022) apt-key method of importing keys.
You can import the key using the following commands:
wget -q https://download.teamviewer.com/download/linux/signature/TeamViewer2017.asc -O- | gpg --dearmor | sudo tee /usr/share/keyrings/teamviewer-archive-keyring.gpg echo "deb [signed-by=/usr/share/keyrings/teamviewer-archive-keyring.gpg] https://linux.teamviewer.com/deb stable main" > /etc/apt/sources.list.d/teamviewer.list
and then running
apt update
again.
When trying to mount a CIFS/SMB share, you see the following error log in dmesg:
[ 139.680974] CIFS: Attempting to mount \\10.10.10.10\test [ 139.686714] CIFS: VFS: cifs_mount failed w/return code = -22
This is a currently a bug in Samba or the Kernel but you can easily work around it by adding vers=2.0to the mount options, either in /etc/fstab or if using mount manually, by using the -o vers=2.0 option. This forces Samba to use SMB version 2.0 which does not have the bug.
This simple bash script will recursively find files in the current directory which start with a space.
find . -name " *"
This command will identify all VCard files in a directory by file content (not by file extensin recursively using the file command (looking for text/vcard MIME types) and move those to a different directory.
mkdir -p ../VCards && find . -type f -exec sh -c '
case $( file -bi "$1" ) in (text/vcard*) exit 0; esac
exit 1' sh {} \; -exec mv -v --backup=numbered {} ../VCards \;Based on this StackExchange post. Also see How to move all images to other directory based on file content, ignoring the filename and How to move all videos to other directory based on file content, ignoring the filename and How to move all OOXML (Word .docx/Excel .xlsx) files to other directory based on file content, ignoring the filename
This command will identify all PDF files in a directory by file content (not by file extensin recursively using the file command (looking for application/pdf MIME types) and move those to a different directory.
mkdir -p ../PDF && find . -type f -exec sh -c '
case $( file -bi "$1" ) in (application/pdf*) exit 0; esac
exit 1' sh {} \; -exec mv -v --backup=numbered {} ../PDF \;Based on this StackExchange post. Also see How to move all images to other directory based on file content, ignoring the filename and How to move all videos to other directory based on file content, ignoring the filename and How to move all OOXML (Word .docx/Excel .xlsx) files to other directory based on file content, ignoring the filename
First open xterm in VT52 mode:
xterm -ti vt52 -tn vt52
Inside the xterm terminal window, open picocom to access the serial port.
picocom -b 115200 /dev/ttyACM0
While the serial port access will be handled by picocom, the terminal emulation (i.e. escape code interpretation) will be handled by xterm.
Install zsh
sudo apt install zsh
Add zsh to list of valid shells
sudo vim /etc/shells
Add to the list
/usr/bin/zsh
Set zsh as default shell
chsh -s /usr/bin/zsh
Double check
$ echo $SHELL
Now you might want to check out https://ohmyz.sh/#install to install a nice theme.
When trying to connect to a USB device, you see an error like
[Errno 13] Permission denied: '/dev/ttyUSB0'
and the USB connection can’t be established.
On Debian & Ubuntu, the /dev/ttyUSBx and /dev/ttyACMx devices are owned by the dialout group. Therefore, the solution is to add your user to the dialout group:
sudo usermod -a -G dialout $USER
After that, you need to logout completely and login again (if in doubt, reboot your computer)!
While you can sometimes quickly solve this issue by running whatever command you want to use as root using sudo, this is not a recommended solution since it will allow the program you’re calling full access to the entire computer – not just access restricted to the USB device. Therefore, this approach poses a significant security risk and additionally, some programs don’t work properly when called using sudo.
The recommended way is to install the current version using pip since the version installed using apt might be out of date:
sudo pip install esptool
After that, you can use esptool.py – note that you need to call it as esptool.py, not just as esptool!
In case you are missing pip , install python3-dev using apt:
sudo apt -y install python3-pip
This simple command will permanently enable IPv4 forwarding on Alpine Linux. Run this as root:
echo net.ipv4.ip_forward=1 | tee -a /etc/sysctl.conf && sysctl -p
My recommendation is to just use the community repository:
echo http://dl-2.alpinelinux.org/alpine/edge/community/ >> /etc/apk/repositories apk add -U tailscale
Now you need to add tailscaled to the autostart list and then start the service so you can use it right now:
rc-update add tailscale /etc/init.d/tailscale start
When trying to use usermod in Alpine Linux, you see the following error message:
-ash: usermod: not found
Install usermod and related tools by adding the community repositories and using
echo http://dl-2.alpinelinux.org/alpine/edge/community/ >> /etc/apk/repositories apk add -U shadow
export GCSFUSE_REPO=gcsfuse-`lsb_release -c -s` echo "deb http://packages.cloud.google.com/apt $GCSFUSE_REPO main" | sudo tee /etc/apt/sources.list.d/gcsfuse.list curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - sudo apt-get update sudo apt-get install gcsfuse
If that doesn’t work (such as for Ubuntu 21.10 impish at the time of writing this post), use the following method:
curl -L -O https://github.com/GoogleCloudPlatform/gcsfuse/releases/download/v0.39.2/gcsfuse_0.39.2_amd64.deb sudo dpkg --install gcsfuse_0.39.2_amd64.deb rm gcsfuse_0.39.2_amd64.deb
This is a summary from the official docs.