slack --silent

This simple tweak helps keep your terminal or system logs cleaner, especially when running Slack from a launcher or custom script.

To achieve this, you can employ the VBoxManage command from the host machine. The command to reduce the time sync threshold is as follows:

vboxmanage guestproperty set {VM_NAME_HERE} "/VirtualBox/GuestAdd/VBoxService/--timesync-set-threshold" 30000

Replace {VM_NAME_HERE} with the name of your specific virtual machine. The value 30000 represents the threshold in milliseconds, meaning if the time drift exceeds 30 seconds, the guest additions time sync service adjusts the VM’s clock. By decreasing the threshold, you ensure more frequent synchronization, enhancing application performance and reliability in time-sensitive environments.

Note: VirtualBox Guest Additions needs to be installed on the guest machine.

ssh -o PubkeyAuthentication=no user@example.com
scp -o PubkeyAuthentication=no user@example.com

or

ssh -o PreferredAuthentications="password" user@example.com
scp -o PreferredAuthentications="password" user@example.com

Here’s a step-by-step guide to setting up passwordless SSH authentication:

1. Generate SSH key pair: On your local machine, generate an SSH key pair if you haven’t already done so. Open a terminal and run the following command:

ssh-keygen -t rsa

This will generate a pair of keys: a private key (usually id_rsa) and a public key (usually id_rsa.pub).

2. Copy the public key to the remote server: Use the following command to copy your public key to the remote server you want to connect to:

ssh-copy-id username@remote_host

Replace username with your username on the remote server and remote_host with the hostname or IP address of the remote server. You will be prompted for your password on the remote server.

If the ssh-copy-id command is not available on your system, you can manually append the content of your public key (id_rsa.pub) to the ~/.ssh/authorized_keys file on the remote server.

3. Configure SSH on the remote server: SSH server configuration should allow public key authentication. On the remote server, open the SSH server configuration file (usually located at /etc/ssh/sshd_config) using a text editor.

Locate the line that starts with #PubkeyAuthentication yes and remove the leading # to uncomment the line. If the line doesn’t exist, you can add it.

Save the changes and exit the text editor.

4. Restart SSH service: Restart the SSH service on the remote server to apply the changes you made to the configuration file. The command to restart SSH depends on your operating system. For example, on Ubuntu, you can use:

sudo service ssh restart

Alternatively, you can use the following command if you are using a system with systemd:

sudo systemctl restart sshd

5. Test the passwordless SSH login: Try to SSH into the remote server without a password:

ssh username@remote_host

Replace username with your username on the remote server and remote_host with the hostname or IP address of the remote server. If everything is set up correctly, you should be able to log in without entering a password.

That’s it! You have successfully set up passwordless SSH authentication. Now you can log in to the remote server without typing your password each time.

First you’ll need to install the following NextCloud App: Preview Generator

Then you’ll have to run the following “occ” command in order to optimize the size of the generated thumbnails:

php ./occ config:app:set previewgenerator squareSizes --value="32 256"
php ./occ config:app:set previewgenerator widthSizes  --value="256 384"
php ./occ config:app:set previewgenerator heightSizes --value="256"
php ./occ config:system:set preview_max_x --value 2048
php ./occ config:system:set preview_max_y --value 2048
php ./occ config:system:set jpeg_quality --value 60
php ./occ config:app:set preview jpeg_quality --value="60"

Once the Preview Generator app has been installed and activated, execute the following “ooc” command:

php ./occ preview:generate-all

This will scan all of your files and will genarate thumbnails. You can add the above command to your nextcloud user’s cron to be executed every 10 minutes eg:

*/10 * * * * php /path/to/your/nextcloud/occ preview:generate-all

$ ssh -o ServerAliveInterval=60 <user>@<ip>

The above will instruct the ‘ssh’ client to sent “alive” packets every 60 seconds.

The following will set the same as default (by adding the option to your ssh client’s configuration file) for each ssh connection.

$echo -e "Host *\n\tServerAliveInterval 60" >> $HOME/.ssh/config

# awk -v d1="$(date --date '-60 min' '+%d/%b/%Y:%T')" '{gsub(/^[\[\t]+/, "", $4);}; $4 > d1' /var/log/nginx/access.log

This example shows how to extract data from /var/log/nginx/access.log for the past 60 minutes – ‘-60 min’.

# yum update --exclude=PACKAGENAME 

Exclude all kernel related packages during update:

# yum update --exclude=kernel*

Exclude gcc and java:

# yum update --exclude=gcc,java

Exclude all gcc and php related packages:

# yum update --exclude=gcc* --exclude=php*

In order to permanently exclude/disable updating of some specific packages you might want to update your dnf.conf or yum.conf eg:

[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exclude=kernel* php*             <---

https://gist.github.com/SwitHak/b66db3a06c2955a9cb71a8718970c592

Happy patching everyone.