Linux

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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 need to get more familiar with Linux and would like to start by running it on my desktop computer. In the past when I tried using CentOS, I quickly went back to Windows because the amount of time it took me to do the smallest task was just to much. However I have been doing some reading and it appears that maybe I just did not install the correct desktop environment or these would have been better choices: Ubuntu, Mint, SUSE.

I learned on Windows, so this is going to be a big shift for me, but I need to learn this skill.

I am looking for the best linux OS for my needs:
1 ) Run MySQL and some tools to write MySQL code as well as build MySQL databases
2 ) Run SQL Server (now runs on Linux) and some tools to manage SQL Server (pretty sure Visual Studio code works on Linux)
3 ) Create a docker playground, since I know nothing of docker...but need to learn
4 ) Powershell and Python code editor
5 ) Email and calendar application where I can combine multiple calendars in a single location like MS Outlook does (ex: personal gmail with work Office 365 in a single view)
6 ) Chat application preferably Slack
7 ) PDF edit and digital signing software (it appears Adobe works on Linux, but I need to sign doc as well)
8 ) I do need to connect to CentOS servers using a terminal, on Windows I use Putty to do this, however I am sure any Linux distro will have a great terminal environment
9 ) Run dual monitors (in the past when I used mint and locked the computer the second …
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we have run a few security scripts over a red hat linux server and one of the issues it has raised is the fact that passwords are available in plain text in an /etc/fstab file. By review of the permissions I can see all users on the server can read this file, so this is not good. I think the /etc/fstab file is being used as there is a link between this server and another for storing documents. I presume amending the ACL on the /etc/fstab file itself from the current presumably default ACL, is not a good idea as it could break things. So what other options are there to prevent users seeing this plain text password in the /etc/fstab file, or what are the best practices in such cases.
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Are there any specific metrics/flags that from a server monitoring perspective you should be notified about on a red hat linux server, which are common for every RHEL server? I need to assess the server monitoring processes for some of our systems, and to have to hand a list of what an admin should be actively monitoring and/or alerted upon from a general health check perspective would be useful, and some indications on how you have set up your monitoring systems, e.g. 3rd party solution, or tools already included with RHEL distribution. I appreciate there are the essentials such as free disc space etc, but having maybe the top 5-10 issues that all should be monitoring for an alerted upon would be useful.
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sonarqube on docker on ubuntu.
i try to install sonarqube 7.7-community with postgres version 11.3
its failed with
 
 ERROR web[][o.a.c.h.Http11NioProtocol] Failed to initialize end point associated with ProtocolHandler ["http-nio-"my-ip-9000"]
sonar      | java.net.BindException: Cannot assign requested address
ERROR web[][o.s.s.a.EmbeddedTomcat] Fail to start web server
at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:113)
at org.apache.catalina.core.StandardService.initInternal(StandardService.java:556)
 WARN  app[][o.s.a.p.AbstractProcessMonitor] Process exited with exit value [es]: 143

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the port 9000 is not occupied.
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Our LAMP stack website was failing to make connection to an azure database, very sporadically but very often, like every 3rd click that you'd hit where it needed to go out to azure for data. The exact errors in the Symfony prod.log was:

Connection Failed:[unixODBC][Microsoft][ODBC Driver 13 for SQL Server]TCP Provider: Error code 0x274C

and

app.ERROR:  error : [unixODBC][Microsoft][ODBC Driver 13 for SQL Server]TCP Provider: Error code 0x68

We tired everything, our web host made sure our ODBC driver was the same on the production server (which had the issue) as it was on our staging server (exact same code base and it did not ever have the issue)... it is exactly the same. All Azure logs and settings looked fine. The production server disk space and RAM have plenty of room.

I finally out of desperation trashed the cache of Symfony on our production server. Since then, actually a bit before then, we haven't had the issue.

What could the issue have been? I need to know what it was to prevent it in the future.
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I am trying to get a better understanding of available options on RHEL for user password policies. I have reviewed /etc/login.defs which I understand to be the standard default options. The settings in there seem quite weak. I can also not see any evidence that you can enforce a password complexity program in this file, e.g. passwords must comprise of certain number of character sets (A-Z, a-z, 1234567890, special characters etc. It does have a minimum length. I have read about pam.conf and files withinin pam.d. I cant see pam.conf at all, indicating its not in use and our understanding is nobody has amended anything in pam.d files to improve things. A couple of questions:

1) can any user with an account on the server change their own password at any point, or can only root change/reset passwords.
2) can you set account lockout policies for failed login attempts and enforce password complexity policies in /etc/login.defs or must you use an additional program on the server, and if the latter, have you any recommendations.
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Can you assist with interpreting the output of getafcl for /etc/passwd and /etc/shadow files on a live server. The output shows as below:

# file: etc/shadow
# owner: root
# group: root
user::---
group::---
other::---

/etc/passwd permissions

# file: etc/passwd
# owner: root
# group: root
user::rw-
group::r--
other::r--

fromwhat I understand security best practice suggests /etc/shadow should only be readable by root (as it contains security sensitive info), and /etc/passwd should only be writable by root as you can upgrade permissions to root if you can edit the file. However, the permissions on /etc/passwd indicate 'user' has rw which indicates read & write permissions. Is this a security flaw or is this the default setting? What does 'user' actually represent, and is it all users on the server, if so this seems like a problem from the offset.
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I used this site to setup a restrictive SFTP server where users can only see files in their folder:

Setup restrictive SFTP users

What I can't find is how to I setup a user that can login and go to everyones folder? I dont want the user to have SSH access and I dont want to use the user I created when building the server.
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Good day. We have a nasty Proxmox kernel error on a RAID1 system: (out of /var/log/messages)

May 10 14:58:37 proxmoxXXX kernel: [57269.175789] scsi target0:1:0: volume handle(0x00be), volume wwid(0x05ac9c5b28c5dbfb)
May 10 14:59:06 proxmoxXXX kernel: [57298.871751] sd 0:1:0:0: attempting task abort! scmd(00000000c23993b1)
May 10 14:59:06 proxmoxXXX kernel: [57298.871758] sd 0:1:0:0: [sda] tag#4 CDB: Write(10) 2a 00 27 5d 21 68 00 00 10 00
May 10 14:59:06 proxmoxXXX kernel: [57298.871762] scsi target0:1:0: volume handle(0x00be), volume wwid(0x05ac9c5b28c5dbfb)
May 10 14:59:06 proxmoxXXX kernel: [57298.871767] sd 0:1:0:0: task abort: FAILED scmd(00000000c23993b1)

Our RAID-controller is: SAS2004 PCI-Express Fusion-MPT SAS-2 [Spitfire] (pretty old LSI low budget controller)
Our Proxmox system is: Virtual Environment 5.4-4 running on Debian 9

The problem seem to occur when the load average climbs over 5-7 (and higher).
Someone mentioned to me maybe upgrading the firmware of the RAID-card but I have not found any drivers yet.
Any ideas where to catch them or any other ideas on this issue ?
Thanks a bunch
Uwe
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i have samba domain controller on ubuntu server.
all server and client is member of domain.
issue is some windows 10 client need to write fqdn of a server to ping or connect to it.
f.x. ping topc.example.local  is ok nut when they ping topc (servername) is no responding for server name
This client ins member of domain and all client has nothing in host file.
how to resolve that?
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Rowby Goren Makes an Impact on Screen and Online
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Rowby Goren Makes an Impact on Screen and Online

Learn about longtime user Rowby Goren and his great contributions to the site. We explore his method for posing questions that are likely to yield a solution, and take a look at how his career transformed from a Hollywood writer to a website entrepreneur.

I have executed the following command on a red hat Linux server
rpm -qa --last 

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to try and determine when the latest updates/patches were applied to the server. I ran this under the context of a non root account but still got some output.

A couple of questions:
--will the output of this command be full/accurate if it was executed under the context of a none root account.
---Secondly, how often are updates issued for red hat Linux, and are they cumulative / is it similar to Microsoft patch releases, and do the updates also cover security vulnerabilities. The last updates listed in the output of command were 2017 which raises some concerns that security bugs have not been patched, and therefore the server is vulnerable.
----Finally, does red hat Linux have a support lifecycle where they only continue to issue patches for certain versions, and if so where can I see where the version currently operated sits in this support lifecycle, e.g. is it still eligible for updates for new bugs/vulnerabilities.
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Can you help me with the correct syntax for getting a getfacl  report for all files and folders within the /etc/ directory, written to a text file. I appreciate this will need to be ran under the context of a root account, so I will log the request with the admin.

I also wanted to use ls -l command to get an inventory of all files stored in all users /home/ directory, again written out to text file, so if someone could help me with the correct syntax to run ls -l over all files/users in the /home/ directory that would be most useful.

this is on a red hat linux 6.8 system.
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i try following docker run on ubuntu 16.04:
docker run --name jenkin-nginx -v /containers/nginx/jenkins/conf.d/nginx.conf:/etc/nginx/nginx.conf -p 80:80 nginx
nginx.conf is :

events{
              }
http {
server {

    listen 80;
    server_name build;

    location ^~ /jenkins/ {

        proxy_set_header        Host $host:$server_port;
        proxy_set_header        X-Real-IP $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header        X-Forwarded-Proto $scheme;

        # Fix the "It appears that your reverse proxy set up is broken" error.
        proxy_pass              http://build:8080/;
        proxy_read_timeout      90;

        proxy_redirect          http://jenkins:8080/ http://build/;

        # Required for new HTTP-based CLI
        proxy_http_version 1.1;
        proxy_request_buffering off;
        # workaround for https://issues.jenkins-ci.org/browse/JENKINS-45651
        add_header 'X-SSH-Endpoint' 'build:50022' always;
    }
}
}

i try to http://build
then i have error :

 *1 "/etc/nginx/html/index.html" is not found (2: No such file or directory),
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Hi,

Greetings.

How do I install Ubuntu server 18.04 LTS 64 bit with GUI enabled(GNome, KDE, etc.)  using VMWare Workstation Pro 15?

Can you please provide me the download URL if any developer has ported Ubuntu Server 18.04 LTS 64 bit with GUI enabled(GNome, KDE, etc.)


Does any website URL offer single .vmdk image for Ubuntu server 18.04 LTS 64 bit with GUI enabled(GNome, KDE, etc.) for download that is compatible with VMWare Workstation Pro 15?

If possible, can you please provide me the URL for a single .vmdk image for Ubuntu server 18.04 LTS 64 bit with GUI enabled (GNome, KDE, etc.) for download that is compatible with VMWare Workstation Pro 15?

Reach out to me for any questions.

Thanks for your support.

Warm Regards,
Sriram
0
Hi Experts,

I am working on an application with Reactjs as front end (Redux , redux thunk, reactjs) and django and nodejs on backend,  I get the following runtime error

 Unhandled Rejection at: Promise {
[1]   <rejected> TypeError: Cannot read property 'facets' of undefined
[1]     at searchComplete (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/search/static/search/reducers/search.js:140:59)
[1]     at search (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/search/static/search/reducers/search.js:246:14)
[1]     at combination (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/redux/lib/combineReducers.js:133:29)
[1]     at dispatch (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/redux/lib/createStore.js:178:22)
[1]     at /home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/redux-thunk/lib/index.js:14:16
[1]     at /home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/react-router-redux/middleware.js:18:18
[1]     at dispatch (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/redux/lib/applyMiddleware.js:45:18)
[1]     at _callee$ (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/search/static/search/actions/search.js:171:15)
[1]     at tryCatch (/home/ubuntu/workarea/sourcecode/ntdl/ntdl/ntdl-2/node_modules/babel-cli/node_modules/regenerator-runtime/runtime.js:65:40)
[1]     at Generator.invoke [as _invoke] 

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Building an Azure Lab

Really looking to have 2-3 2012 servers maybe a few windows clients (windows 10)

Whats best size to use for this, I see the smallest size is B1ls is Linux only ,

I'm doing it with a MSDN work subscription, will mostly be deallocated just looking to start this and need some advice if possible
0
I want to add a character to the 5th column in a csv file using linux

Example- input file
1234,3334,,,ghghghg,55,88
12,34,,,avdfr,5,8899


Add the letters AUID- to the data in the 5th column

Expected result in a new file

1234,3334,,,AUID-ghghghg,55,88
12,34,,,AUID-avdfr,5,8899

I know there should be some awk syntax that does this but not sure what the exact syntax would be. if you could give me a bit of an explination as well as the answer, so I can make adjustments to you answer to fix several files that I want to process
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Hi,

I have java maven build project. I need to connect to a linux box and transfer few files from the local machine to a folder to linux and run the commands.

Please help me which maven dependency i can use and connect to the linux box. This is for writing cucumber automated tests using java.
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Hi, I have a deprecated each() function on line 89 of this script. Could you please help me with a replacement for this deprecated function?

<?php
/*
 * test_smtp_message.php
 *
 * @(#) $Header: /home/mlemos/cvsroot/PHPlibrary/test_smtp_message.php,v 1.4 2002/08/12 04:46:15 mlemos Exp $
 *
 */

require("mimemessage/email_message.php");
require("mimemessage/smtp_message.php");
require("mimemessage/smtp.php");

function mime_mail($server, $from_name, $from_address, $pass, $to_address, $subject, $message, $html_message = "", $attachments = array(), $other_headers = "") {
/*
    	$attachment=array(
    		"Data"=> "This is just a plain text attachment file named attachment.txt .",
    		"Name"=>"attachment.txt",
    		"Content-Type"=>"automatic/name",
    		"Disposition"=>"attachment"
    	);
*/

  $debug = date("H:i:s");
  $error1 = "";


	$reply_name=$from_name;
	$reply_address=$from_address;
	$error_delivery_name=$from_name;
	$error_delivery_address=$from_address;
	$to_name="";
	
  $email_message=new smtp_message_class;
	
  if($server=="gmail") {
    $email_message->protocol = "tls://";
    $email_message->smtp_port=465; /* SMTP server address */
	  $email_message->smtp_host="smtp.gmail.com"; /* SMTP server address */
	  $email_message->smtp_user=$from_address; /* authentication user name */
	  $email_message->smtp_password=$pass; /* authentication password */
  }
  else {
    global $use_local_smtp;
    $use_local_smtp = true;
    

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Angular Fundamentals
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Angular Fundamentals

Learn the fundamentals of Angular 2, a JavaScript framework for developing dynamic single page applications.

Does access control list testing/reporting in red hat linux follow the same principles as windows, e.g. you can only produce a report (access control list) of who can access a file/directory if the account you are running the tests from has access to it yourself. E.g. if you are not a root level account, can you only check who can access files/directories that you have access to. If you try and get an access control report for a file/folder you don't have access to, will you get some sort of access denied error?

I have been looking at the ls command for my own development. I think this may produce similar to windows CACLS command (but also gives a bit more info such as size etc, what would the correct syntax be to check permissions of a file, is it simply ls path, or is there a bit more to it?

I assume most critical information (e.g. system configuration files) are by default locked down to root access only, so it would take an admin to start amending settings to make a default copy of linux less secure in terms of critical server wide configuration files. Or can other things amend settings above and beyond naive administrator amendments.
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Hello and thanks in advance for any insight the community can provide. I'm working on a WordPress site hosted on GoDaddy's Business Launch Hosting Plan, so it's a Linux  environment.  The challenge I have is with trying to use a SQL query to display data from an external MS SQL server to the WordPress site.
 
When I started looking into this, I wanted to use a plugin (WPDataTable) to do this. I cleared one error when trying to connect to the server by enabling pdo_sqlsvr. Then I received the following error:

wpDataTables could not connect to mssql server. mssql said: There was a problem with your SQL connection - SQLSTATE[IMSSP]: This extension requires the Microsoft ODBC Driver 13 for SQL Server to communicate with SQL Server. Access the following URL to download the ODBC Driver 13 for SQL Server for x64: http://go.microsoft.com/fwlink/?LinkId=163712

I called GoDaddy to see how to resolve the error. They said our website would need to be hosted in their Windows environment (Plesk) in order to communicate with a MS SQL server, otherwise, I'd have to export data from MS SQL to i.e., CSV to then import to MySQL.

- Someone today (not godaddy) said there's potentially an option if I had root access to set up Microsoft’s freetds configuration, which I'm pretty sure I don't have through Godaddy (we're not on the VPS hosting plan) and this goes beyond my level of expertise.
- I'm assuming that whether attempting to do this with a plugin, or writing code, MS SQL server…
0
Hi Team,

Iam going to work on clustering  application servers for our application.  Iam new to this , any help on below topics really appreciated

1. Introduction to cluster concepts
2. Load Balancing
3. How  to create an application cluster
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Hi, I need help troubleshooting the last 2 errors on the results of a PCI compliance scan for my server web.vacationpeople.net for my SSL certificate on port 21:

"One or more certificates in the chain cannot be validated."

"The certificate's issuer certificate could not be identified. Errors in the certificate chain prevent the certificate from being verified."

The certificate passes all tests in all other ports but port 21.

My server configuration:

Red Hat Enterprise Linux Server 7.6 (Maipo)
Plesk Onyx

Could you please give me some assistance as to how I can resolve this to be able complete validation on this scan?

Thanks,

Jorge Batres
0
Do any of the config files in the \etc\ directory give any clues on the last time certain RHEL accounts were used/logged into. I can query /etc/shadow but I think the numerical value in there is actual days since password last set, not days since last login/last login date. It would also be helpfull, if at all possible, to identify the date an account was created.

Also is there a command that will show the exact version number/build of RHEL.

And using putty.exe and running a command with a >>output.txt result, how can you tell where the putty software defaults to when saving the output of a file, e.g. on commandprompt in windows I can see where its going to write the files too unless I specify a new path, but in putty connected to RHEL I cant actually tell where it is going to write the output to.
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is there any quick command that can be run via putty once connected to a RHEL server, to determine the privileges granted to that account you are logged in with, e.g. is it a root account, does it have su/sudo privileges etc. I have been given an account to a test server for some security checks, but I am pretty sure a lot of it is not completing as the account has limited privileges. But as it is a fairly new area to me, I could do with a quick command you can run via putty once connected with this account to list what security privileges it actually does have.
0

Linux

66K

Solutions

33K

Contributors

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.