Posts Tagged ‘task’

Windows unable to delete file, file locked unlocking with Unlocker tiny tool

Wednesday, April 13th, 2016


If you want to delete some file on a Windows server or Desktop but you get the a dialog with an error saying:

"This action can't be completed because the folder or a file in it is open in another program"


Then you need to find out which Program is preventing the file from deletion / locking the file, I've earlier blogged on how to check which process locks file with tasklist or wmic Windows commands

However some users might prefer to not bother with command line check what is locking a file and then killing the Process manually with taskmanager (taskmgr.exe) but do both file unlocking from one single gui interface, that's especially for lazy novice users, gamers and most of Desktop Windows users.

If you're one of those lazy users you will appriace

Unlocker – a useful utility for unlocking files, it will help you figure out which file is using a file what program is using the file you're prevented to delete.
Unlocker is the tool for you if you get any of below error messages, when you try to delete a file:


  • Cannot delete folder: It is being used by another person or program
  • Cannot delete file: Access is denied
  • There has been a sharing violation.
  • The source or destination file may be in use.
  • The file is in use by another program or user.
  • Make sure the disk is not full or write-protected and that the file is not currently in use.


If you stumble unto an locked file once you download and install Unlocker tool and launch the tool ( in case it disappers in future a mirror of Unlocker tool here ).
Once installed if you click properties over the file which is refused to be deleted you will get a new menu such as in below screenshot:

NB! Beware while installing Unlocker you might be offered to install a bunch of malware (make sure you deselect it). Also Unlocker's site is made in a way so the Download button could easily be confused with some Google Adsense


Click on the file that is being locked and choose the Unlocker button, for example if you have a bunch of Videos installed and the video is being locked by VLC clicking on the file you will be shown VLC like in below screenshot



As you see you're shown the Process PID that is being used by the file the full path to the locking program and you have the option to quickly kill the process or unlock the file. Note that at some cases unlocking a file used by some critical program lets say Microsoft Word / Excel or OneNote could cause you a data loss, so before unlocking a file make sure you know what you're doing.

For more advanced users that still prefer GUI to find out what is Locking a file you can also check out Microsoft Process Explorer (advabced task manager) like tool.
If you haven't tried Process Explorer be sure to take a look at it as its a great tool for Win SysAdmins:

Process Explorer is very handy if you want to explore which .DLL (Windows Libraries) are used by a Process / Program




Linux: How to see / change supported network bandwidth of NIC interface and get various eth network statistics with ethtool

Monday, January 19th, 2015

If you're a novice Linux sysadmin and inherited some dedicated servers without any documentation and hence on of the first things you have to do to start a new server documentation is to check the supported TCP/IP network speed of servers Network (ethernet) Interfaces. On Linux this is very easy task to verify the speed of LAN card supported Local / Internet traffic install ethtool (if not already preseont on the servers) – assuming you're dealing with Debian / Ubuntu Linux servers.

1. Install ethtool on Deb and RPM based distros

dedi-server1:~# apt-cache show ethtool|grep -i desc -A 3
Description: display or change Ethernet device settings
 ethtool can be used to query and change settings such as speed, auto-
 negotiation and checksum offload on many network devices, especially
 Ethernet devices.

dedi-server1:~# apt-get install –yes ethtool

ethtool should be installed by default on CentOS / Fedora / RHEL and  syntax is same like on Debs. If you happen to miss ethtool on any (SuSE) / RedHat / RPM based distro install it with yum

[root@centos:~] # yum -y install ethtool

2. Get ethernet configurations

To check the current eth0 / eth1 / ethX network (Speed / Duplex) and other network related configuration configuration:

dedi-server5:~# ethtool eth0

Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full

        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: off
        Supports Wake-on: pumbag
        Wake-on: g
        Current message level: 0x00000001 (1)
        Link detected: yes

Having a NIC configured to act as Duplex is very important as Duplex communication enables LAN card to communicate both sides (Sent / Receive) packets simultaneously.


Probably most interesting parameters for most admins are the ones that are telling whether the NIC UpLink is 10megabyte / 100 megabyte or 1Gigabyte as well as supported Receive / Send ( Transfer ) speeds of LAN, a common useful ethtool admin use to just show current LAN ethernet interface speed:

server-admin1:~# ethtool eth0 |grep -i speed
        Speed: 1000Mb/s


To get info about NIC (kernel module / driver) used with ethtool:

dedi-server3:~# ethtool -i eth0 driver: e1000e
version: 1.2.20-k2
firmware-version: 1.8-0
bus-info: 0000:06:00.0

3. Make LAN Card blink to recognize eth is mapped to which Physical LAN

Besides that ethtool has many other useful use cases, for example if you have a server with 5 lan or more LAN cards, but you're not sure to which of all different EthX interfaces correspond, a very useful thing is to make eth0, eth1, eth2, eth3, etc. blink for 5 seconds in order to identify which static IP is binded physically to which NIC , here is how:

ethtool -p eth0 5

Then you can follow the procedure for any interface on the server and map them with a sticker 🙂

Ethtool is also useful for getting "deep" (thorough) statistics on Server LAN cards, this could be useful to identify sometimes hard to determine broadcast flood attacks:

4. Get network statistics with ethtool for interfaces

dedi-server5:~# ethtool -S eth0|grep -vw 0
NIC statistics:
     rx_packets: 6196644448
     tx_packets: 7197385158
     rx_bytes: 2038559235701
     tx_bytes: 8281206569250
     rx_broadcast: 357508947
     tx_broadcast: 172
     rx_multicast: 34731963
     tx_multicast: 20
     rx_errors: 115
     multicast: 34731963
     rx_length_errors: 115
     rx_no_buffer_count: 26391
     rx_missed_errors: 10059
     tx_timeout_count: 3
     tx_restart_queue: 2590
     rx_short_length_errors: 115
     tx_tcp_seg_good: 964136993
     rx_long_byte_count: 2038559235701
     rx_csum_offload_good: 5824813965
     rx_csum_offload_errors: 42186
     rx_smbus: 383640020

5. Turn on Auto Negotiation and change NIC set speed to 10 / 100 / 1000 Mb/s

Auto-negotiation is important as an ethernet procedure by which two communication devices (2 network cards) choose common transmission parameters such as speed, duplex mode, and flow control in order to achieve maximum transmission speed over the network. On 1000BASE-T basednetworks the standard is a mandatory. There is also backward compatability for older 10BASE-T Networks.

a) To raise up NIC to use 1000 Mb/s in case if the bandwidth was raised to 1Gb/s but NIC settings were not changed:

dedi-server1:~# ethtool -s eth0 speed 1000 duplex half autoneg off

b) In case if LAN speed has to be reduced for some weird reason to 10 / 100Mb/s


dedi-server1:~# ethtool -s eth0 speed 10 duplex half autoneg off

dedi-server1:~# ethtool -s eth0 speed 100 duplex half autoneg off

c) To enable disable NIC Autonegotiation:

dedi-server1:~# ethtool -s eth0 autoneg on

6. Change Speed / Duplex settings to load on boot

a) Set Network to Duplex on Fedora / CentOS etc.

Quickest way to do it is of course to use /etc/rc.local. If you want to do it following distribution logic on CentOS / RHEL Linux:

Add to /etc/sysconfig/network-scripts/ifcfg-eth0

vim /etc/sysconfig/network/-scripts/ifcfg-eth0

ETHTOOL_OPTS="speed 1000 duplex full autoneg off"

To load the new settings restart networking (be careful to have physical access to server if something goes wrong 🙂 )

service network restart

b) Change network speed / duplex setting on Debian / Ubuntu Linux

Add at the end of /etc/network/interfaces

vim /etc/network/interfaces

post-up ethtool -s eth0 speed 100 duplex full autoneg off

7. Tune NIC ring buffers

dedi-server1:~# ethtool -g eth0

Ring parameters for eth0:
Pre-set maximums:
RX:             4096
RX Mini:        0
RX Jumbo:       0
TX:             4096
Current hardware settings:
RX:             256
RX Mini:        0
RX Jumbo:       0
TX:             256

As you can see the default setting of RX (receive) buffer size is low 256 and on busy servers with high traffic loads, depending on the hardware NIC vendor this RX buffer size varies.
Through increasing the Rx/Tx ring buffer size , you can decrease the probability of discarding packets in the NIC during a scheduling delay.
A change in rx buffer ring requires NIC restart so (be careful not to loose connection to remote server), be sure to have iLO access to it.

Here is how to raise Rx ring buffer size 4 times from default value:

ethtool -G eth0 rx 4096 tx 4069

Allowing MySQL users access from all hosts – Fixing mysql ERROR 1045 (28000): Access denied for user ‘root’@’’ (using password: YES)

Friday, June 20th, 2014


I recently migrated MySQL database server from host A to host B (, because I wanted to have the mysql database server on a separate machine (have separation of server running services and have a dedicated mysql server).

MySQL server host (running on localhost previously was set from my mysql config my.cnf to listen and serve connections on localhost with

bind-address =

). MySQL is used by a Tomcat running Java application on localhost and my task was to set the Tomcat to use the MySQL database remotely to MySQL host B (new remote hostname where MySQL is moved is and is running on IP

Migration from MySQL Db server 1 (host A) to MySQL Db server 2 (host B) is done by binary copying the mysql database directory which in this case is (as it is a Debian server installed MySQL), the standard directory where mysql stores its database data is /var/lib/mysql ( datadir = /var/lib/mysql in /etc/mysql/my.cnf)

Binary copying of data from MySQL db (host A) to MySQL Db (host B) is done with rsync

After migrating and trying to login on migrated mysql  database on with mysql cli client:

remotesysadmin:~$ mysql -u root -p

I got following error:

ERROR 1045 (28000): Access denied for user 'root'@'' (using password: YES)

To fix the issue I had to login remotely from old migration server mysql (host A) cli:

mysql:~$ mysql -u root -p -h

and  run SQL commands:

GRANT USAGE ON *.* TO 'root'@'' IDENTIFIED BY 'secret-mysql-pass';

Query OK, 0 rows affected (0.03 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)

Another way to solve the problem is to add the root user to be able to connect from any host (Enable MySQL root access from all host), to do so issue:


Note: In newer version of MySQL, flush privileges could be omitted.

Another approach if you want to substitute access from localhost for all users and enable all users to be able to authenticate to mysql remotely is to execute SQL Query:

UPDATE USER SET host='%' WHERE host='localhost';

Allowing all users to be able to connect from anywhere on the internet is a very bad security practice anyways, if you already have a tight firewall setup and you can only access the server via specific remote IP addresses allowing MySQL access from all hosts / ips should be ok.

Start Stop Restart Microsoft IIS Webserver from command line and GUI

Thursday, April 17th, 2014

For a decomissioning project just recently I had the task to stop Microsoft IIS  on Windows Server system.
If you have been into security for a while you know well how many vulnerabilities Microsoft (Internet Information Server) Webserver used to be. Nowadays things with IIS are better but anyways it is better not to use it if possible …

Nomatter what the rason if you need to make IIS stop serving web pages here is how to do it via command line:

At Windows Command Prompt, type:

net stop WAS

If the command returns error message to stop it type:

net stop W3SVC

Just in case you have to start it again run:

net start W3SVC


For those who prefer to do it from GUI interface, launch services.msc command from Windows Run:

> services.msc


In list of services lookup for
IIS Admin Service and HTTP SSL
a) (Click over it with right mouse button -> Properties)
b) Set Startup type to Manual
c) Click Stop Button

You're done now IIS is stopped to make sure it is stopped you can run from cmd.exe:

telnet localhost 80

when not working you should get 'Could not open connection to the host. on port 80: Connection failed' like shown up in screenshot.

Currency converter Free Desktop Software for Microsoft Windows

Saturday, December 8th, 2012

Business or not a business entity, in the mostly globalized world it is almost inevitable to go on at least monthly basis without a need for some kind of currency convertion. Of course there are plenty of websites allowing Free Money Convertion services out there. However as I'm not a big fan of the Software as a Service (SAS). I don't like other people to be able to sniff what kind of money, amounts I'm intending to convert as well as I don't like google or other search engine to profile me how frequently I'm converting or intending to convert money. Thus today I did a quick research what kind of Free and  Open Source Software FOSS is available to do the money convertion operation custom on my own webserver or my desktop PC. Though It was not exactly what I was looking for I found a Windows Desktop Software -CConverter which is capable of convertions between mostly if not all Currencies around the world. I'm not a m$ Windows user myself, but I was glad to know a Free Software exists for the task. CConverter is definitely a piece of soft useful for Businesses and People. In future if I do my own business it would be nice to know of this little handy soft existence and I will put it in action (to save costs) and add confidentiality to my business money transaction / convertions. Below is the two screenshots of CConverter I found on the project's sourceforge website:

Desktop Currency converter program cconverter windows desktop currency converter program

cconverter money desktop currency converter m$  windows software in action $$$

PHP system(); hide command output – How to hide displayed output with exec();

Saturday, April 7th, 2012

I've recently wanted to use PHP's embedded system(""); – external command execute function in order to use ls + wc to calculate the number of files stored in a directory. I know many would argue, this is not a good practice and from a performance view point it is absolutely bad idea. However as I was lazy to code ti in PHP, I used the below line of code to do the task:

echo "Hello, ";
$line_count = system("ls -1 /dir/|wc -l");
echo "File count in /dir is $line_count \n";

This example worked fine for me to calculate the number of files in my /dir, but unfortunately the execution output was also visialized in the browser. It seems this is some kind of default behaviour in both libphp and php cli. I didn't liked the behaviour so I checked online for a solution to prevent the system(); from printing its output.

What I found as a recommendations on many pages is instead of system(); to prevent command execution output one should use exec();.
Therefore I used instead of my above code:

echo "Hello, ";
$line_count = exec("ls -1 /dir/|wc -l");
echo "File count in /dir is $line_count \n";

By the way insetad of using exec();, it is also possible to just use ` (backtick) – in same way like in bash scripting's .

Hence the above code can be also written for short like this:

echo "Hello, ";
$line_count = `ls -1 /dir/|wc -l`;
echo "File count in /dir is $line_count \n";


How to add a range of virtual IPs to a CentOS and Fedora Linux server

Monday, July 18th, 2011

Recently I had the task to add a range of few IP addresses to as a virtual interface IPs.

The normal way to do that is of course using the all well known ifconfig eth0:0, ifconfig eth0:1 or using a tiny shell script which does it and set it up to run through /etc/rc.local .

However the Redhat guys could omit all this mambo jambo and do it The Redhat way TM 😉 by using a standard method documented in CentOS and RHEL documentation.
Here is how:

# go to network-script directory[root@centos ~]# cd /etc/sysconfig/network-scripts
# create ifcfg-eth0-range (if virtual ips are to be assigned on eth0 lan interface[root@centos network-scripts]# touch ifcfg-eth0-range

Now inside ifcfg-eth0-range, open up with a text editor or use the echo command to put inside:


Now save the /etc/sysconfig/network-scripts/ifcfg-eth0-range file and finally restart centos networking via the network script:

[root@centos network-scripts]# service network restart

That’s all now after the network gets reinitialized all the IPs starting with and ending in< will get assigned as virtual IPs for eth0 interface
Cheers 😉

Runing sudo command simultaneously on multiple servers with SSHSUDO

Tuesday, June 21st, 2011

ssh multiple server command execute
I just was recommended by a friend a nifty tool, which is absoutely nifty for system administrators.

The tool is called sshsudo and the project is hosted on

Let’s say you’re responsible for 10 servers with the same operating system let’s say; CentOS 4 and you want to install tcpdump and vnstat on all of them without logging one by one to each of the nodes.

This task is really simple with using sshsudo.
A typical use of sshsudo is:

[root@centos root]# sshsudo -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 yum install tcpdump vnstat

Consequently a password prompt will appear on the screen;
Please enter your password:

If all the servers are configured to have the same administrator root password then just typing one the root password will be enough and the command will get issued on all the servers.

The program can also be used to run a custom admin script by automatically populating the script (upload the script), to all the servers and issuing it next on.

One typical use to run a custom bash shell script on ten servers would be:

[root@centos root]# sshsudo -r -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 /pathtoscript/

I’m glad I found this handy tool 😉

Make picture transparent with the Gimp on Linux

Tuesday, November 16th, 2010

GIMP Logo make picture transparent with GIMP on GNU / Linux
I’m trying to learn some basic design this days as an attempt to fill my huge missing gap of knowledge in graphic processing.
I’ve always been not too good with visual stuff and always been focused on the command line and console, however since
some time design started being quite interesting thing to me and I found it quite handy and challenging to learn some basic designing.

I’m not really a Windows guy and thus my Photoshop skills are next to zero.
Since The Gimp is the substitute for Photoshopfor Linux users and I had a task for one of the websites I’m developing to make some pictures for the website transparent, therefore I had to learn how to make pictures transparent with The Gimp
After some reading online and some experimenting with GIMP it appeared to me it’s very easy to actually make pictures transparent with the GIMP.
So I’ve come with a small article here on how to make image or a picture transparent with Gimp in simple steps in order to help people who are trying to achieve the same easy task:

1. Open Gimp and place your mouse cursor on the picture

Here, Press the 2nd or 3rd mouse button to show menu.

2. Select Layer -> Transperancy -> Alpha to Selection

In that menu selectSelect Layer -> Transprerancy -> Alpha to Selection

Gimp Alpha to Selection Menu

3. Use Fuzzy Select Tool and select the picture background

Gimp fuzzy select background

4. From Gimp Window pane main menu choose the Clear option

Edit -> Clear (Delete)
gimp edit clear menu

That’s all now your picture background should be removed if some parts of the picture still needs to be purged just follow the above step and remove them.
I should say I thought making picture transparent with GIMP would be a more complex task than it really was, quite nice one more step in my development as a designer 🙂