Author Archives: ServerAdmin

Nginx – redirecting with a regular expression

NGINX rewrite rules are quite simple and easy to understand. They change the part or complete URL in a client request (for example in case when you want to redirect your users from http to https, to another domain/subdomain, etc)

For example, the simple redirect with code 301 (moved permanently) from to can be achieved with:

server {
    listen 80;
    listen 443 ssl;
    return 301 $scheme://$request_uri;

In this case, $scheme and $request_uri are nginx variables and they are used to capture and replicate the values from the original request URL ($scheme is the protocol – ‘http’ or ‘https’ and $request_uri is the portion of the URL that follows the domain name – for example ‘/getUser?id=blabla’)


To add ‘www’ before the domain:

server {
    listen 80;
    listen 443 ssl;
    return 301 $scheme://$request_uri;

To remove the ‘www’:

server {
    listen 80;
    listen 443 ssl;
    return 301 $scheme://$request_uri;

To redirect all requests which doesn’t match already defined server and location blocks to specific home page
For example subdomain whose IP address points to the server but the server doesn’t have defined server or location block for this subdomain

server {
    listen 80 default_server;
    listen 443 ssl default_server;
    server_name _;
    return 301 $scheme://;

Also, you can add $request_uri variable above.

Forcing all Requests to Use SSL/TLS

server {
    listen 80;
    return 301$request_uri;

Redirecting a subdomain with a regular expression to new subdomain

server {
    listen 80;
    server_name ~^((?<subdomain>.*)\$;
    return 301 $scheme://${subdomain}$request_uri;

Redirecting subdomain to specific dir (with a regular expression)

server {
    listen 80;
    server_name ~^((?<subdomain>.*)\.)(?<domain>[^.]+)\.(?<tld>[^.]+)$;
    return 301 $scheme://${domain}.${tld}/${subdomain};


Change hostname on Mint Linux / Ubuntu – Howto

To change your hostname, you’ll need to edit /etc/hostname file with

sudo nano /etc/hostname

The file content is very simple. It contains the current hostname and all you need to do is to replace it with the new one, save and exit

After you save the changes, open /etc/hosts file and replace the current hostname with the new one near IP address.


... old-hostname


... new-hostname

Save file and exit.

Now, enter the next command

sudo hostname new-hostname

Your computer’s hostname will be changed immediately. (The change won’t appear in the terminal until you reopen it again)

This method will work on all Debian based distros (Ubuntu, Kubuntu, ….)

Cx UI framework

If you’re working on a new admin and dashboard application and you’re looking for a quality UI framework which is fast and easy to use, check the Cx. It is inspired by React, Redux, Ext JS, Angular and other open-source libraries and frameworks, but as they said, it tries to cover all you need for a modern web app.

During the promo period, you can buy it with 50% discount (coupon code: LAUNCH-PARTY). For more information, please visit the official page –


Command line system information

If you’re not sure which components are installed in your server/pc, you can use inxi which is a command line system information script. It will show you the system hardware, CPU, drivers, Xorg, Desktop, Kernel, GCC version(s), Processes, RAM usage, and a wide variety of other useful information.

For example:

myPC@myPC ~ $ inxi -F
System:    Host: myPC Kernel: 3.19.0-32-generic x86_64 (64 bit) Desktop: Cinnamon 2.8.8
           Distro: Linux Mint 17.3 Rosa
Machine:   System: LENOVO product: 20E1000BSC v: ThinkPad W550s
           Mobo: LENOVO model: 20E1000BSC v: SDK0E50510 WIN Bios: LENOVO v: N11ET34W (1.10 ) date: 08/20/2015
CPU:       Dual core Intel Core i7-5600U (-HT-MCP-) cache: 4096 KB 
           clock speeds: max: 3200 MHz 1: 901 MHz 2: 981 MHz 3: 2195 MHz 4: 2199 MHz
Graphics:  Card-1: Intel Broadwell-U Integrated Graphics
           Card-2: NVIDIA GM108GLM [Quadro K620M]
           Display Server: X.Org 1.17.1 drivers: nvidia (unloaded: intel)
           Resolution: 1920x1080@59.9hz, 1920x1080@60.0hz
           GLX Renderer: Quadro K620M/PCIe/SSE2 GLX Version: 4.5.0 NVIDIA 352.63
Audio:     Card-1 Intel Wildcat Point-LP High Definition Audio Controller driver: snd_hda_intel
           Card-2 Intel Broadwell-U Audio Controller driver: snd_hda_intel
           Sound: Advanced Linux Sound Architecture v: k3.19.0-32-generic
Network:   Card-1: Intel Ethernet Connection (3) I218-LM driver: e1000e
           IF: eth0 state: up speed: 1000 Mbps duplex: full mac: 54:ee:75:cc:11:4a
           Card-2: Intel Wireless 7265 driver: iwlwifi
           IF: wlan0 state: up mac: 18:5e:0f:ee:f8:aa
Drives:    HDD Total Size: 768.2GB (17.1% used) ID-1: /dev/sda model: LITEON_LCH size: 512.1GB
           ID-2: /dev/sdb model: ADATA_SP600NS34 size: 256.1GB
Partition: ID-1: / size: 28G used: 9.4G (37%) fs: ext4 dev: /dev/sdb1
           ID-2: /home size: 195G used: 60G (33%) fs: ext4 dev: /dev/sdb3
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 50.0C mobo: N/A gpu: 48C
           Fan Speeds (in rpm): cpu: 2466
Info:      Processes: 229 Uptime: 1:09 Memory: 2341.5/15748.3MB Client: Shell (bash) inxi: 2.2.28

Install FreeRADIUS – talloc library not found

In case you’re trying to install FreeRadius 3 on the latest CentOS (currently 6.8), there is a chance you’ll see the next error

checking for _talloc in -ltalloc in /opt/lib... no
configure: WARNING: talloc library not found. Use --with-talloc-lib-dir=<path>.
configure: error: FreeRADIUS requires libtalloc

To fix this problem, simple install libtalloc-devel package with

yum install libtalloc-devel

Disable bluetooth on startup – howto

I’m using Mint Linux and I noticed that the Bluetooth adapter is always on (I turned it off in the previous  session). I’m using Bluetooth from time to time, but I don’t like to see it on when I don’t need it. Besides, it wastes battery.

You can turn it off per session (as I did), but next time it’s right back on which annoys me.  As I can see, I’m not the only one who is affected with this.

The solution is set InitiallyPowered parameter to false.

sudo nano /etc/bluetooth/main.conf

Search for the entry:

InitiallyPowered = true

and change the value to:

InitiallyPowered = false

Next time you boot, it should be down.

In case this doesn’t help, try to turn off bluetooth service by adding “/etc/init.d/bluetooth stop” inside /etc/rc.local file (before the “exit 0” line)

Fix “Failed To Fetch” Apt error Howto

Google announced plans to discontinue 32-bit Google Chrome for Linux and it has. On some 64bit Ubuntu based systems (Mint/Kubuntu/Xubuntu,..), during update process you may notice the next error:

“Failed to fetch Unable to find expected entry ‘main/binary-i386/Packages’ in Release file (Wrong sources.list entry or malformed file)”

To fix this error you’ll need to make some changes in google-chrome.list

Open /etc/apt/sources.list.d/google-chrome.list file and add [arch=amd64] before “http”

deb [arch=amd64] stable main

Do not edit or replace any other text in this file. Save the changes and refresh your package list with

sudo apt-get update

The “failed to fetch” APT error should no longer appear

Hacked Linux Mint ISOs

Bad news for Mint users who downloaded ISO files few days ago (20th Feb)…

Some dude found the way to replace the official Mint 17.3 Cinnamon ISOs with the cracked ISOs (with backdoor inside)

More details can be found here:

Also, as Clem announced, the forum database was compromised and you should change your password on all sensitive websites as soon as possible (in case you used the same password on other sites)

More details:

Unable to export database in MySQL Workbench – delayed-insert error

In case you’re using MySQL Workbench for creating dumps please keep in mind that version 6.3.5 has one annoying bug.
After update, the first time I tried do create dump, the complete process failed with the next error:

mysqldump: [ERROR] unknown variable 'delayed-insert=FALSE'

As I can see, this error occurs on various systems (Windows / MAC / Linux) and it was fixed once (6.1.x was also affected – LINK)

For now, you can only apply temporarily fix:

Open file (as root) (located in /usr/lib/mysql-workbench/modules for Ubuntu/Mint/Debian distros)

Find the line

"delayed-insert":["Write INSERT DELAYED statements rather than..."

and insert # at the begin of this line (to comment it out)
Save file and restart Workbench. Check the Advanced option and note that this option is not available

Note: Windows users
For 32bit systems, is located in C:\Program Files\MySQL\MySQL Workbench XXX\modules
For x64 systems, is located in C:\Program Files (x86)\MySQL\MySQL Workbench XXX\modules)

The bug fix is easy to apply but it was announced months ago we’re still waiting for update… So shame…

More info: