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.

Share tech news, updates, or what's on your mind.

Sign up to Post

The issue is strait forward.  On Ubuntu 18.04 I have deleted reolve.conf from the /ETC dir.  Resolv.conf appears to get recreated on reboot but it does not contain any DNS server entries save  This will not work, you cannot edit the file as it is symbolically linked.  How do I correct, and provide it with the correct entries.  I was trying to install Dnsmasq.  The following commands were issue

john@VBserver1:~$ sudo systemctl stop systemd-resolved
john@VBserver1:~$ sudo ls -lh /etc/resolv.conf
lrwxrwxrwx 1 root root 37 Feb 17 21:35 /etc/resolv.conf -> /run/systemd/resolve/stub-resolv.conf
john@VBserver1:~$ sudo rm /etc/resolv.conf
john@VBserver1:~$ echo "nameserver" > /etc/resolv.conf
-bash: /etc/resolv.conf: Permission denied
john@VBserver1:~$ sudo echo "nameserver" > /etc/resolv.conf   This one is where the failure results.
-bash: /etc/resolv.conf: Permission denied
error starting ubuntu vm
i did this before i restartvm
hi am not able to ping another vm but am able to ping the same vm from another vm
no internat no gui after installing oracle linux

I am creating hyper V CentOS VM but it seems never can reboot to server UI screen,  I see this screen when I was configuration the disk but I gave it 500GB, can't see why it can't see it.

CentOS disk space

any reaosn why ?

disk space in total:

disk space in total
Dear Gurus
I have a old AIX machine which has MicroFocus Cobol 5.1 running on it.
Now I need to move it to RHEL Version 7.
Is there a way we can find if this will be compatible with Red Hat Linux 7 or not.
If not, which version of Linux it will be compatible with.

Best Regards,
We have a slow responding web application running on a local server, it is running on MariaDB 10.4.8, PHP7.2 FPM and nginx on Ubuntu 19.04.

It doesn't look to be due to a lack of resources as far as I can see using top and looking at free memory & CPU usage. I have used iotop to look at disk usage and I think this is probably OK as far as I can see.

Can anybody help me find a solution to our slow application performance or at least point me in the right direction to diagnosing the problem? I have attached a couple of screen grabs of TOP and IOTOP for reference.

This is driving me a bit nuts and would really appreciate any help!

Many Thanks,
hi am not able to connect to my linux via vnc from window
I need to install a Let's Encrypt SAN Certificate, so that multiple domains can use Let's Encrypt. I am currently running AWS Linux (basically RedHat). Does anyone have a good "go to" set of directions on how to create a Let's Encrypt SAN Certificate on AWS Linux?

Hi Experts

In this server, we have a directory called /important  
We need to backup this directory every hour to a different path to /backup
Then check if the backup successful we need to remove the data from /important  
For this, we need you to write for us a shell script, which can do this task for us automatically every hour  
Note: we need to specify the time stamp for the backup files

i have this question and i need full answer i manged just to fix the first part which includes making the backup with time stamp

but i need the other part

1-  check if the backup successful remove the data from /important


backup=/backup/important-`date +%Y-%m-%d-%H-%M`.tar
tar -cvf "$backup" /important

hi error installing oracle linux i have attach the disk
Hi Experts

we have in our environment NAgios-XI  the commercial version of Nagios

and i am monitoring file systems under red-hat box  and everything was ok no issues

yesterday i extend the filesystem from 1.3 TB to 2.9 TB and after one day i start to get critical massage from Nagios-XI

[root@nagios ~]# /usr/local/nagios/libexec/check_nrpe -H -t 30 -c check_disk -a '-w 50% -c 80% -p /oracle/RAN/oraarch'
DISK CRITICAL - free space: /oracle/RAN/oraarch 2291546 MB (77.93% inode=100%);| /oracle/RAN/oraarch=648895MB;1471509;588603;0;2943018

but this is not true the file system status like this

/dev/mapper/oraarch-oraarch                         2.9T  632G  2.2T  22% /oracle/RAN/oraarch

so only 22% used from this file system

i am monitoring another file systems on the same box and the everything ok just this file system so it cannot be agent issue on the red hat box

any idea here

How do I get ssh access back to my centos linux vm if I'm locked out due to selinux policies?

My coworker turned on some selinux policies and now we can't ssh back into the linux vm which is hosted on azure cloud.

This is a centos vm hosted on Azure cloud. I'm not able to ssh into the machine anymore. How do I get inside the machine to disable the policy?
A dual boot computer, Windows and Linux, ..
In Windows the LInux computer's partition was deleted.
Now when the computer tried to load it looks for the Linux Grub..
how can this be repaired?  So that it will boot into Windows?
I'm having issues with my haproxy servers (running Ubuntu 16.04) rejecting new connections (or timing them out) after a certain threshold. The proxy servers are AWS c5.large EC2's with 2 cpus and 4GB of ram. The same configuration is used for both connection types on our site, we have one for websocket connections which typically have between 2K-4K concurrent connections and a request rate of about 10/s. The other is for normal web traffic with nginx as the backend with about 400-500 concurrent connections and a request rate of about 100-150/s. Typical cpu usage for both is about 3-5% on the haproxy process, with 2-3% of the memory used for the websocket proxy (40-60MB) and 1-3% of the memory used for the web proxy (30-40MB).

Per the attached config, the cpus are mapped across both cpus, with one process and two threads running. Both types of traffic are typically 95% (or higher) SSL traffic. I've watched the proxy info using watch -n 1 'echo "show info" | socat unix:/run/haproxy/admin.sock -' to see if I'm hitting any of my limits, which does not seem to be the case.

During high traffic time, and when we start to see issues, is when our websocket concurrent connections gets up to about 5K and web requests rate gets up to 400 requests/s. I mention both servers here because I know the config can handle the high concurrent connections and request rate, but I'm missing some other resource limit being reached. Under …
A computer has a Linux Mint installation and a Windows 10 installation - in dual boot.
Currently there is not enough space with the current portioning size to install Office 365 on the Windows partition.
Therefore the Linux partition has to be made smaller.
How can this be done?
Thanks in advance.
We have an Ubuntu Server (Xenial) that will never touch the internet.  We can't query the Ubuntu Repo from another Ubuntu Server that has Internet access, how can we get the packages we need, with all dependencies?
Ive usually installed PHP via:-
sudo apt install php libapache2-mod-php php-mysql

Open in new window

Which works great and installs the latest version of PHP and configures everything fine :-)

Problem is I want some of my sites to run on PHP 5 (for historical purposes), some to run on the current version of PHP 7 and some to run on a future version of PHP 7 for testing.

On my hosting website, I can add a line into the vhost configuration to tell it what version of PHP to run, for example to run PHP7 I just add this into the htaccess file and it runs the site with PHP 7:-
AddType application/x-httpd-php70 .php
This is exactly what I want to do, however all the guides Ive found online talk about running everything under the same version, but not individual sites.

Anyone got any ideas on this?

Ideally I want to download different versions of PHP into a folder \PHP\PHP7.3\ and then inside htaccess point to use \PHP\PHP7.3\ or something different.

Im using Ubuntu server with Apache if that helps, and this is only for development purposes, not production.
I get file "courier-imap-5.0.8.tar" (attached) but am not sure about its setup in Ubuntu. Please help.
Hi Experts

we have ERP system SAP running on red hat Linux 7  using oracle 12C

from time to time our file system which reserved for ora logs  get full so fast out of the sudden

we are not able to know the root cause which  

process or transaction or user  generate such amount of logs

do you know anyway or tool to know such info

Jpg file does exist in "/var/www/pict" path, but html file below is not able to show Jpg file. Why?

        <!--div align="center"-->
        <div class="container" style="background:url('../pict/ID-10028343.jpg') no-repeat center top; Height:780px; Width:1220px; background-size:100% 100%; margin:0 auto; ">

Open in new window

I am wondering how can we monitor the permission on char file using monit application

I have below char file


and below monitrc config

check file dev_null with path /dev/null
if failed permission 666 then exec "chmod 666 /dev/null" as uid root and gid wheel

But it doesn't seems to work when file /dev/null has permission 600

I really appreciate any help on that.
Dear All,

In the past few weeks, I noticed the mailcleaner gateway was being targeted with bruteforce and spam attacks from Russia and Iran, I deployed country block plugin on my firewall and blocked entire CIDR for both Russia and Iran and kept an eye on Mailcleaner for any attacks with authentication attempts.

Since then, I noticed the mailcleaner disk has went up from 25% to 76% with the path /var/mailcleaner/spam/ and all domains included full of spam files with size up to 35 GB.

I have few questions to clean some space and prior to that also.

Are those spam files ?
Are they released or not?
Is it safe to delete them?

Thank you
nextcloud issue:
i try to move ownership from one to other user:
both users has logged in to web access
i do the following from command line
sudo -u www-data php occ files:transfer-ownership "source-user" "destination-user

The target user is not ready to accept files. The user has at least to be logged in once.

What is wrong here?
I added a disk to RedHat 7 on Azure. After re-boot server, I cannot ssh to the server .
The following is the steps I did referring .
Could you help me to resolve this issue?

1. I created a disk on Azure Portal.

2. Confirmed file types of existing disks.
[servername]$ df -T
Filesystem     Type     1K-blocks     Used Available Use% Mounted on
devtmpfs       devtmpfs    970560        0    970560   0% /dev
tmpfs          tmpfs       980972        4    980968   1% /dev/shm
tmpfs          tmpfs       980972    37856    943116   4% /run
tmpfs          tmpfs       980972        0    980972   0% /sys/fs/cgroup
/dev/sda2      xfs       30929148 30877300     51848 100% /
/dev/sda1      xfs         508580   116672    391908  23% /boot
/dev/sdb1      ext4       4061824    16380   3819400   1% /mnt/resource
tmpfs          tmpfs       196196        0    196196   0% /run/user/1008
tmpfs          tmpfs       196196        0    196196   0% /run/user/995

3. Confirmd a disk added by dmeg. sdc was added.
[servername]$ dmesg | grep SCSI
[    0.374123] SCSI subsystem initialized
[    1.075264] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 248)
[    3.073908] sd 3:0:1:0: [sdb] Attached SCSI disk
[    3.078645] sd 2:0:0:0: [sda] Attached SCSI disk
[12159.133527] sd 5:0:0:0: [sdc] Attached SCSI disk

4. Executed fdisk
[servername]$ sudo fdisk …






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.