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Linux is a UNIX-like open source operating system with hundreds of distinct distributions, including: Fedora, openSUSE, Ubuntu, Debian, Slackware, Gentoo, CentOS, and Arch Linux. Linux is generally associated with web and database servers, but has become popular in many niche industries and applications.

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I have a Linux system that I need to modify few configuration files while the system is not be running.
For this reason, I have booted from a ISO file, therefore, the root directory is ISO not the local drive.
Since the script tries to modify few files with the fixed path /etc/, /var,...etc. I need to chroot the local disk.
what is the best way to do this operation, do I need to change any permissions or take ownership of directories or files.

Thank you for quick prompts.
PMI ACP® Project Management
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PMI ACP® Project Management

Prepare for the PMI Agile Certified Practitioner (PMI-ACP)® exam, which formally recognizes your knowledge of agile principles and your skill with agile techniques.

SSH connection refused when running SSH (putty) from my WINDOWS PC a  an ORACLE LINUX running on the same PC on Oracle Virtual BOX.

PUTTY displays the error:
PUTTY Network  error:  Connection refused  on

Sure, something is wrong. Could you help?

Kylin not getting started

here is the below error which I'm getting

kafka dependency is /opt/apache-kylin-2.2.0-bin/lib/kafka-clients-1.0.0.jar
Retrieving Spark dependency...
Error: Could not find or load main class exists
ERROR: Unknown error. Please check full log.
Good evening,

I am trying to build a Fedora server with a Raid 1+0.

The mother board is B450-F
Socket AM4

I was able to get Fedora 24 to somewhat work but I made a newbie mistake on a partition and re- installing the system again.
But here is my main problem:

I  have 4 identical solid state drives and want it to be set-up as Raid 1+0.
The hardware does support it but when I try to install linux after the raid has been set-up.  The linux install does not recognize the raided drives.
If I have to deal with CentOS 7 that would be fine.  I just need a system that handle Motif programming, and Fedora and CentOS still support this.

In help would be great
Hi Team,

I want to extract the group name and owner name from the ls -l command output , below is the command which I have written , not able to get the output .

ls -l | sed -n '/^-/s/^-.* [0-9] \([[:alpha:]] [[:alpha:]]\).*/\1/p'

-rw-r--r--. 1 root  root      0 Nov 12 23:53 abc.txt
-rw-------. 1 root  root   2629 Nov 11 01:17 anaconda-ks.cfg
-rw-r--r--. 1 root  root    139 Nov 12 22:13 CALNOV
-rw-r--r--. 1 root  root      0 Nov 12 23:54 cc
-rw-r--r--. 1 root  root      0 Nov 13 00:05 $file
-rw-r--r--. 1 root  root     48 Nov 12 21:56 filename
-rw-r--r--. 1 root  root  41955 Nov 11 01:17 install.log
-rw-r--r--. 1 root  root   9154 Nov 11 01:11 install.log.syslog
-rw-r--r--. 1 root  root   2682 Nov 12 22:42 logdata
-rw-r--r--. 1 root  root   1054 Nov 12 21:58 LOGFILENAME
-rw-r--r--. 1 root  root     81 Nov 13 07:22 meals
-rw-r--r--. 1 root  root     82 Nov 13 05:20 names
-rw-r--r--. 1 root  root     79 Nov 13 07:27 newnames
-rw-r--r--. 1 root  root    139 Nov 12 22:09 novcal
-rw-r--r--. 1 root  root      0 Nov 12 23:52 test
-rw-r--r--. 1 root  root     13 Nov 10 21:25 test1
-rw-r--r--. 1 root  root      0 Nov 12 23:52 test2

i want to show only root root in the output  for all the files
Hi Team,

I need to know the Linus command which will list the no of core in a cpu for both VM and physical machines.
Hi Team,
I want to know the difference in the output of the below unix commands

ls -F

ls -F I get the output with directories suffixed with a / , but some regular files suffixed with * , @ symbols. Why is it so?

[root@localhost ~]# ls -F
abc.txt          Desktop/     install.log.syslog  Public/     testfile*
accounts/        Documents/   logdata             Templates/  test.ksh*
anaconda-ks.cfg  Downloads/   LOGFILENAME         test        typescript
backup/          $file        Music/              test1       Videos/
CALNOV           filename     novcal              test123@
cc               install.log  Pictures/           test2

ls -d list only the current directory , but ls -d */  , is there any other command to list only directories.
Dear Experts, I'm testing Oracle 11g on Centos 7 64b.

I installed Oracle but could not connect to the globalDB by sqlplus, it keeps showing error: ORA-12514: TNS:listener does not currently know of service requested in connect even I start the Oracle Database

I also attached the response file from Installation process. These are the details of listener and tnsname files:

lsnrctl status:

Can you please help? Many thanks!
zgrep 'xyz'  abc.log.2018111212| grep '|[1-9][0-9][0-9][0-9][0-9]|0000' | wc -l

i am trying to figure out what above grep doing?

what is meaning of

wc -l means some kind of word count?
what is -l

any good links or resources or video tutorials to master greps and awk and sed end to end to debug server logs?

please advise

My redhat (guest OS) having issue for not able to resolve the hostname like google.com but able to ping

I didn't do anything at all just to ensure that it can ping Google first and my network subnet like when my redhat added a NAT Network adapter without issue.

After that I connect my fortinet vpn client thr IPSec and still can ping and resolve my private cloud thr hostname.

Next day I do the same thing like connect to my iPad 4G network to my Hp laptop wifi.

Can ping and resolved on my hp laptop even being connected to vpn.

The guest os redhat from virtualbox on nat can ping but not able to resolve now.

Why yesterday can and today can't without changing anything?

10 Tips to Protect Your Business from Ransomware
10 Tips to Protect Your Business from Ransomware

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I need help freeing up space on a Linux Server Using CLI. The OS is Gentoo version 3.16. I don't really have much experience with Linux especially using CLI. I deleted a folder in a share (from within a Windows Server) but that didn't free up the space. But I did notice that the usedsnaps column for that share, that the usedsnap space went up after removing that folder. I don't want to just delete any snapshot. I don't know what I could delete really. They don't have any other backups, so I'm nervous to just delete a snapshot. Any assistance would be greatly appreciated!

Thank You,
Ubuntu 16.04 Mail Server - Inbound for internal networks, but send-only to external relay.

I need to setup a Ubuntu server to allow servers to send alerts and logs to it and send-only to an external mail relay. What would be the best way to do this using Postfix? I am so new to mail servers and having a hard time figuring out what I need to do. Most tutorials have a send-only local mail server or a full-fledged email server, not really something in between. Any guidance would be appreciated...
I have a FreeBSD and ubuntu server.
I crate a cronjob to execute in specific time. but the command that I do required a full privilege on system... so how I can make the cronjob work with root for example ?
how to enable xhost in Linux server

I am  getting the below error
xhost +
xhost:  unable to open display ""

please advise
Dear Experts,

I am thinking to use SSIS to do the following procedure.

(1) copy many files to Linux machines. then
(2) execute a Linux program (command) to analysis those files. The program will output the result to the local Linux drive
(3) when (2) is done, then pull the result back to Windows machine

For (1) I am thinking of FTP task (by FTP or SFTP)

how about the task of (2) and (3) ?  Could you please help ... Thanks
i am using ubuntu and cannot print graphics png file.  it will print libreoffice writer or calc though.
Linux. I need to set up a script that I can run via cron in the middle of every night to copy / back up specific folders into another directory. I want all folders, files and permissions and attributes copied. The goal is to have a 24 hour old copy that I can restore in case a user screws up their files. Example:

/usr/home/thisuser/web_master would be copied / backed up to /usr/home/mainuser
/usr/home/thisotheruser/web_master would be copied / backed up to /usr/home/mainuser
/usr/home/andanotheruser/web_master would be copied / backed up to /usr/home/mainuser

Each night, the copy / back up would overwrite the one from 24 hours ago.

How do I set this script up, and what type of file extension should the script be?
Is it possible to create a cross-platform desktop application in Visual Studio 2017 that will run in both Windows 10 and Linux environments (how is it done)?  
I don't see any "New Project" options that stand out, nor much information on the web.

This is using new Meinberg NTP appliance to replace the existing old one. This new one has been configured and operational right now. We have hundreds SuSE 11 servers and MS Windows 2008 or 2012 servers. All these servers sync to the existing ntp appliance for time, and being working fine for the past years.

We intend to replace this new one with the old one. Now, we are doing a test on the selected SuSE server. Please see the host names of these ntp appliances and 1 virtual name

                                        old ntp appliance:          sinaad21.abc.corp 
                                        new ntp appliance:        sina3mbg01.abc.corp
                                        general ntp name:         sinntp01.abc.corp   

We are using normal dns alias(or cname) for this ntp naming. Currently, sinaad21 is the alias pointing to sinntp01.abc.corp in our DNS server. Whereas, on all SuSE servers, in /etc/ntp.conf, a setting as below is configured,

                          sinntp01.abc.corp iburst

This is how we do the test with steps as follows,

                           a. On our DNS server, remove the alias of sinaad21, and change it to, sina3mbg01.
                           b. On a test SuSE server, restart the nscd to clear the dns cache.
                           c. On a test SuSE server, ping sinntp01.abc.corp, and we get the result of IP address of sina3mbg01(that means the …
Acronis True Image 2019 just released!
Acronis True Image 2019 just released!

Create a reliable backup. Make sure you always have dependable copies of your data so you can restore your entire system or individual files.

I am trying to install XRDP on a Red Hat 7.5 server I have been following some instructions I found on the internet


The problem I am having is when I get to the part in the article to run the command  (yum install xrdp tigervnc-server xterm) there is a Dependencies problem;

I have followed the article to the letter up to (yum install xrdp tigervnc-server xterm) command and everything works until that point

I think I am missing something rather simple here, any Ideas?

Resolving Dependencies
--> Running transaction check
---> Package xrdp.x86_64 1:0.9.8-1.el7 will be installed
--> Processing Dependency: xorgxrdp for package: 1:xrdp-0.9.8-1.el7.x86_64
---> Package xterm.x86_64 0:295-3.el7 will be installed
--> Processing Dependency: libXaw.so.7()(64bit) for package: xterm-295-3.el7.x86_64
--> Running transaction check
---> Package libXaw.x86_64 0:1.0.13-4.el7 will be installed
---> Package xorgxrdp.x86_64 0:0.2.8-1.el7 will be installed
--> Processing Dependency: xorg-x11-server-Xorg(x86-64) = 1.19.5 for package: xorgxrdp-0.2.8-1.el7.x86_64
--> Finished Dependency Resolution
Error: Package: xorgxrdp-0.2.8-1.el7.x86_64 (epel)
           Requires: xorg-x11-server-Xorg(x86-64) = 1.19.5
           Installed: xorg-x11-server-Xorg-1.20.1-5.1.el7.x86_64 (@rhui-rhel-7-server-rhui-rpms)
               xorg-x11-server-Xorg(x86-64) = 1.20.1-5.1.el7
I have a wordpress website on AWS EC2 Ubuntu Linux. I am not good in this department of coding but I get by. I just used created a Load Balancer and attached it to my EC2 instance. I am trying to force SSL (HTTPS) on anyone who visits my site. I have 90% of it correct.  if you visit:

http://www.Example.com (Redirects to https://www.Example.com)

it works perfectly with Secure. But if you go to

then it goes to a UNSECURE site. and stays on Example.com

In my ".htaccess" file at the very top I have the code below.  So what is the problem? I thank you for the help.

#Force www:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^Example.com [NC]
RewriteRule ^(.*)$ https://www.Example.com/$1 [L,R=301,NC]

# Begin force ssl
<IfModule mod_rewrite.c>
# RewriteEngine On
 RewriteCond %{SERVER_PORT} 443
 RewriteRule ^(.*)$ https://Example.com/$1 [R,L]

Open in new window

I've installed a version of the Unifi Controller to the AWS cloud before, but it's been over 6 months. I went to install a second, built my EC2 on AWS as per the instructions, but then I couldn't get the UNIX commands to work after install. It was flawless before. I'm not getting anywhere with searching on the error.

Here's the command from the instructions that fails after launching the instance:

Once you connect to the Server and are greeted with the Ubuntu Command Line Interface (CLI), do the following:
5.1. Add the Ubiquiti repository to /etc/apt/sources.list:
echo "deb http://www.ubnt.com/downloads/unifi/debian stable ubiquiti" | sudo tee -a /etc/apt/sources.list

HERE's what I get...

[ec2-user@ip-172-31-22-106 ~]$ echo "deb http://www.ubnt.com/downloads/unifi/debian stable ubiquiti" | sudo tee -a /etc/apt/sources.list
tee: /etc/apt/sources.list: No such file or directory
deb http://www.ubnt.com/downloads/unifi/debian stable ubiquiti

The instructions are found at:  https://help.ubnt.com/hc/en-us/articles/209376117-UniFi-Install-a-UniFi-Cloud-Controller-on-Amazon-Web-Services

Has anyone RECENTLY gotten the Unifi Controller installed on AWS?  I didn't even get to the point of installing the controller. Just made it to the point where it would pull it down.

I have been following a PDF from APC to user PowerChute Business Edition over a Serial connected Smart UPS to talk with the Linux install in the vMa appliance on a VMWARE ESXi 6.7 environment.  (Please don't suggest Network Shutdown, I've got the free version of VMware.)
It is entitled, "Using ESXi with PowerChute Business Edition"  
On page 17-18, it tells us to add the ESXi host using vMA, and asks for HOST IP address, user root and the password.  However, I get an error message that it won't add the HOST because if fails the SSL connection test.
When I run>  sudo vifp listservers    none are listed because they couldn't connect.

It seems like such a straight forward process, it detects the UPS and is ready to go, but I can't had the VM host to the PowerChute Business Edition installation.

I have ONE APC UPS which I'd like to have gracefully shut down 2 VM's and the VMHost in the event of a power outage.

Should I just run PCBE on one of my VM's and execute a shutdown command for the 2nd VM and let the VMHost crash on its own?

Has anyone got a solution?
OS: RedHat / CentOS

I can use realmd to allow specific Active Directory users/groups to log in to a Linux server.  
a1) The default behavior after joining AD and enabling these AD users to log in is: log in as ADUserName@mydomain.com, provide AD password when prompted, and you're in
b1) On login, the bash prompt looks like: ADUserName@mydomain.com@servername.  
c1) I add ADUserName@MYDOMAIN.COM to sudoers, and these users have admin rights if they need it
It all works just fine.

I had a request to make it so that (users who can't bear to type a few more characters) Ad users could log in, using their Ad password, but without having to specify the domain name
So, I make a few changes to /etc/sssd/sssd.conf and it kinda works.  I think I'm missing something.
Now, it looks like this
a2) log in as ADUserName (note: not providing name of AD domain anymore), provide AD password when prompted, and you're logged in.  So far, so good
b2) the bash prompt looks like: ADUserName@servername.  Not ideal.  This is not a local user, IMO the bash prompt should include the AD domain name.  How do I change this back?
c2) the sudoers file had previously been modified to include ADUserName@mydomain.com.  Now, the logged-in AD user can no longer use sudo.  To fix this, I had to modify the sudoers file again, specifying ADUserName instead of ADUserName@MYDOMAIN.COM.  Again, far from ideal.  This might be confusing to anyone except the person who originally set this up - not good.

Hi Expert,

I have a SFTP job which is failing while transfer file for source to dest using "put" command.  As put command only works for single file.

Here my requirement is i want to transfer all the files available in "source/dir1/dir2" and want to merge them into single file then wanna SFTP.

Note:The script should also need to check how many files are there in the source directory before merge them!

thanks in advance.






Linux is a UNIX-like open source operating system with hundreds of distinct distributions, including: Fedora, openSUSE, Ubuntu, Debian, Slackware, Gentoo, CentOS, and Arch Linux. Linux is generally associated with web and database servers, but has become popular in many niche industries and applications.