Category: Linux

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Databases Linux MySQL Ubuntu

Mysql root user has no GRANT option on Ubuntu

If your mysql root user has no grant option on Ubuntu, here’s the procedure to fix this:

First you will have to start mysql without using the grant tables

sudo systemctl edit mysql

This will open an editor, add the following lines and save/quit the editor

[Service]
ExecStart=
ExecStart=/usr/sbin/mysqld --skip-grant-tables

Issue the following commands:

sudo systemctl daemon-reload 
sudo systemctl start mysql

You can now connect to mysql using just the following command (without password)

mysql

Now change the user settings as follows:

mysql> UPDATE mysql.user SET Grant_priv = 'Y', Super_priv = 'Y' WHERE User = 'root';
Query OK, 0 rows affected (0.02 sec)
Rows matched: 1  Changed: 0  Warnings: 0
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.18 sec)

Now issue the first commands again (uptil the systemctl start mysql command), but remove the lines you’ve added to the mysql config.

Categories
Linux

Installing OpenVas on Kali gives error about ospd-openvas.service failing

I am installing openvas on kali linux. when starting openvas with gvm-start I get an error Job for ospd-openvas.service failed because the control process exited with error code. What is causing this and how to fix this ?

The cause of this is a permission issue on the openvas logs. The fix is quite easy:

chmod 666 /var/log/gvm/openvas.log
gvm-start

The problem should be fixed.

Categories
Linux

How to remove all cover art from MP3s.

Open a terminal window and go to your MP3 folder. Run the following command (you might have to install eyeD3 first for our linux distribution.) :

eyeD3 *.mp3 --remove-all-images
Categories
Linux Red Hat Ubuntu

Bash: remove trailing slash from a variable

Suppose you have a variable containing a directorypath:

#!/bin/bash
directorytouse="/home/myhome/whateverdirectory/"

If you try to test in your bash script if the directory exists, then it will fail because of the trailing slash:

if [ ! -d "${directorytouse} ] 
then
    echo -e "directory does not exist!"
fi

The easiest way to remove this / if it is present is to use shell parameter expansion:

if [ ! -d "${directorytouse%/}" ]
then
    echo -e "directory does not exist!"
fi

This will get rid of the trailing slash if there is one. If there is no trailing slash present, then nothing will happen.

Categories
Linux Red Hat Ubuntu

Help, my terminal shows graphical characters instead of normal text

If you have ever used cat or tail to accidentally show a binary file, you will have noticed your terminal show graphical garbage instead of readable text. As shown in the screenshot below:

You will find several suggested fixes on the internet for this, including:

  • type CTRL-C a few times to make sure you are on a new line and then enter ‘reset‘ and tap enter.
  • output the ASCII SI (shift in) character, decimal value 15. This can be entered with CTRL+O and should work if the reset command doesn’t work. Just enter ‘echo CTRL+V CTRL+O’ on the command line
  • enter the command ‘stty sane’, followed by ‘tput rs1’ on the command line.

The only one that worked for me is entering the following (blindly, since you can ‘t read what your are typing) on the terminal prompt:

echo -e "\033c"

A good practice is to define an alias in your startup script with the following command:

alias resetterminal='echo -e "\033c"'

Next time you have this problem, you can then type (blindly) ‘resetterminal’ to fix the problem.

Categories
Linux Red Hat Ubuntu

Vi (or Vim) session no longer responding?

If your Vi or Vim session is hanging and is not responding to anything, then it might be because you pressed CTRL+S accidentally (out of habbit). To fix this, just press CTRL+Q to unblock the session.

Categories
Dell XPS15 Laptop Linux Ubuntu

No wifi or no external monitor on Dell XPS-15

If your wifi card is not available after booting your Dell XPS-15 laptop (with Ubuntu 20.04 or 22.04), or your external monitor refuses to display anything, please try the following:

start up your laptop without your power supply plugged in, connect with wifi, and/or your external monitor and only then plug in your power supply.

This fix works everytime for me.

Categories
Linux

Ubuntu: reset monitor settings to default

If you want to reset your monitor settings to default through the terminal (your second screen is broken and the settings are ‘shown’ there and you don’t want to restart your laptop), you can use the following command:

xrandr -s 0
Categories
Linux Ubuntu

Ubuntu Server – CTRL-ALT-DEL

If you press CTRL-ALT-DEL on a Ubuntu Server the server will be shut down without asking any confirmation or password. This is of course not a good idea.

To disable this, enter the following commands as root:

systemctl mask ctrl-alt-del.target
systemctl daemon-reload
Categories
Linux

Linux: removing commands from history

If you want to remove some commands from your bash history use the following command:

history -d 1001

where 1001 is the number of the history line. Of course this might add another problem: the command ‘history -d 1001’ is now added to your history.

How to avoid a command getting in your bash history?

If you want to execute a command and don’t want it to get in your history list (because it contains sensitive data, or you just don’t want to clutter your history), start the command with a space.

For this to work the environment variable $HISTCONTROL has to be set to ‘ignorespace’ or ‘ignoreboth’.

export HISTCONTROL=ignorespace