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Shell script to monitor MariaDB replication and send email alert about server health status
Here is a simple shell script to notify secondary read-only replica (slave) MariaDB server health status failure via email and push notification. Master-slave data replication allows you to copy databases to multiple MariaDB servers. It is useful for backup, data recovery, load balancing, and much more. See how to configure SSL-protected MariaDB replication between a master and slave server.
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The post Shell script to monitor MariaDB replication and send email alert about server health status appeared first on nixCraft.
2024-07-25T12:51:45Z
2024-07-25T12:51:45Z
Vivek Gite
How to install incus server on Debian 12/11
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Incus is a free and open-source project for the next-gen container management platform. It is a fork of LXD (the container hypervisor). It can manage both Linux containers and virtual machines. Let us see how to install the stable version of the Incus server on Debian 11 or 12 and deploy both containers and VMs for fun and profit.
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The post How to install incus server on Debian 12/11 appeared first on nixCraft.
2024-07-23T08:25:44Z
2024-07-23T08:25:44Z
Vivek Gite
How to upgrade OpenSUSE 15.5 to 15.6 using the CLI
The most recent release of OpenSUSE Linux, version 15.6 "Leap," is now available. This version incorporates the SUSE Linux Enterprise (SLE) source and community developments, making it the ideal option for a stable Linux experience for users, developers, and system administrators. This page provides instructions on upgrading from OpenSUSE version 15.5 to 15.6 using the command-line interface (CLI).
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The post How to upgrade OpenSUSE 15.5 to 15.6 using the CLI appeared first on nixCraft.
2024-06-30T11:03:25Z
2024-06-30T11:03:25Z
Vivek Gite
lnav – Awesome terminal log file viewer for Linux and Unix
It is no secret that whether you are a developer or sysadmin, you need to use log files to troubleshoot errors on your Linux and Unix systems. You use tools like grep, tail, cat, or journalctl to view log files. However, you may need help with so many log files. These essential Unix tools are suitable for basic text but fall short when dealing with many log files. You can get tired from sifting through endless lines of log files. The lnav utility is here to the rescue! It is a powerful log file viewer that goes beyond the basics. It understands your logs by identifying timestamps, log levels, and other vital details. You can run SQLite SQL queries against your standard log files and build reports for your needs. Let us see how to install and use the lnav tool quickly.
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The post lnav – Awesome terminal log file viewer for Linux and Unix appeared first on nixCraft.
2024-06-16T11:04:42Z
2024-06-16T11:04:42Z
Vivek Gite
How to find out AWS EC2 instances type over SSH
AWS offers various instance types, and sometimes, you need to know which one you are using or which one has been deployed by someone else (another developer or sysadmin) for a project. Don't worry. Here are some commands to find the EC2 instance type over SSH without logging into the AWS console. These commands works with any Linux distro or FreeBSD Unix systems.
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The post How to find out AWS EC2 instances type over SSH appeared first on nixCraft.
2024-05-26T11:51:12Z
2024-05-26T11:51:12Z
Vivek Gite
How to add interface to vnstat to database for monitoring
vnStat is a network traffic monitor for Linux and Unix-like systems. It logs network traffic at different intervals and doesn't require root permissions to run. The implementation involves two commands: vnstat for querying traffic information and vnstatd for data retrieval and storage. Let's see how to add a network interface to vnstat after installation for monitoring purposes.
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The post How to add interface to vnstat to database for monitoring appeared first on nixCraft.
2024-05-26T05:56:00Z
2024-05-26T05:56:00Z
Vivek Gite
sttr – Awesome Linux & Unix tool for transformation of the string
sttr demo
The sttr is a free and open-source command-line tool in Golang that lets you easily change and modify text. You can perform transformation operations on the string, such as hashing text, string manipulation, and more. sttr is beneficial for developers and *nix users requiring swift modification to strings or files directly via the command line or TUI. It is helpful in your scripting, data processing, and automation tasks at the CLI.
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The post sttr – Awesome Linux & Unix tool for transformation of the string appeared first on nixCraft.
2024-05-24T21:17:45Z
2024-05-24T21:17:45Z
Vivek Gite
SSH Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys
I'm trying to login using ssh keys but server is only allows to login me using a password. The following message is logged into my Linux or Unix server /var/log/secure or /var/log/auth.log file:
Feb 25 06:36:50 ns5 sshd[26681]: Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys2
Here is another message:
May 24 18:28:35 ls-www-1 sshd[531320]: Connection closed by 18.1.2.3 port 43640 [preauth]
May 24 18:28:44 ls-www-1 sshd[531322]: Authentication refused: bad ownership or modes for file /home/admin/.ssh/authorized_keys
May 24 18:28:44 ls-www-1 sshd[531322]: Connection closed by authenticating user admin 18.1.2.3 port 43650 [preauth]
How do I fix this problem?
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The post SSH Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys appeared first on nixCraft.
2024-05-24T19:23:28Z
2024-05-24T19:23:28Z
Vivek Gite
How to upgrade Alpine Linux 3.19 to 3.20
I am using Alpine Linux v3.18 or v3.19 with my LXD/Incus server. How do I upgrade Alpine Linux v3.19 to Alpine Linux v3.20? How can I upgrade Alpine Linux v3.18 to Alpine Linux v3.20?
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The post How to upgrade Alpine Linux 3.19 to 3.20 appeared first on nixCraft.
2024-05-24T11:25:52Z
2024-05-24T11:25:52Z
Vivek Gite
How to uninstall packages marked “rc” on Debian / Ubuntu Linux
In Debian and Ubuntu Linux, an "rc" status package means the package has been uninstalled, but its configuration files remain on the disk and take up space. Sometimes, certain directories are also in the /var/ directory. When you type the sudo apt remove pkg1 command, it deletes most of the data, but config files are left alone in case you reinstall that package again. You can free up disk space by removing unwanted config files.
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The post How to uninstall packages marked “rc” on Debian / Ubuntu Linux appeared first on nixCraft.
2024-05-22T09:30:57Z
2024-05-22T09:30:57Z
Vivek Gite
How to reload .vimrc file without restarting vim on Linux/Unix
I am a new vim text editor user. I usually load ~/.vimrc using :vs ~/.vimrc for configuration. Once edited my ~/.vimrc file I need to reload it without having to quit Vim session. How do I edit my ~/.vimrc file and reload it without having to restart Vim on Linux or Unix-like system?
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The post How to reload .vimrc file without restarting vim on Linux/Unix appeared first on nixCraft.
2024-05-19T11:03:00Z
2024-05-19T11:03:00Z
Vivek Gite
How to temporarily disable IPv6 in Linux
Sometimes, you may need to temporarily disable IPv6 in the Linux using net.ipv6.conf.all.disable_ipv6 kernel variable for testing purposes. You can use the sysctl command to turn IPv6 connectivity on or off without rebooting the system. For example, observe how your app or network reacts when IPv6 connectivity is suddenly lost and only IPv4 is available.
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The post How to temporarily disable IPv6 in Linux appeared first on nixCraft.
2024-05-18T20:18:54Z
2024-05-18T20:18:54Z
Vivek Gite
TCPDump: Capture and Record Specific Protocols / Port Traffic
How do I capture a specific protocol or port, such as 80 (HTTP) or 443 (HTTPS), using the TCPDump tool under Linux/UNIX? How do I record traffic with TCPDump and find problems later on with my network or server issues? Let's dive into the nitty-gritty of capturing and analyzing your network traffic for trapshooting network and server issues.
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The post TCPDump: Capture and Record Specific Protocols / Port Traffic appeared first on nixCraft.
2024-05-17T21:00:03Z
2024-05-17T21:00:03Z
Vivek Gite
How to find ulimit for user on Linux
How can I find the correct ulimit values for a user account or process on Linux systems?
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The post How to find ulimit for user on Linux appeared first on nixCraft.
2024-05-16T21:57:31Z
2024-05-16T21:57:31Z
Vivek Gite
How to Set Up UFW Firewall on Ubuntu 24.04 LTS in 5 Minutes
A Ubuntu 24.04 LTS comes with UFW (uncomplicated firewall) that protects the desktop or server against unauthorized access. UFW is an easy-to-use frontend app for a Linux packet filtering system called Netfilter or nftables. Traditionally, Netfilter/nftables rules are set up or configured using the iptables command or nft command by developers and sysadmins. However, new Ubuntu Linux users and developers unfamiliar with firewall concepts find Netfilter/nft syntax confusing. Hence, the ufw project provides an easy-to-use frontend for Ubuntu 24.04 LTS Linux server and desktop. This quick guide makes setting up UFW on Ubuntu 24.04 LTS extremely simple. It provides step-by-step instructions for developers and sysadmins to secure their servers efficiently.
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The post How to Set Up UFW Firewall on Ubuntu 24.04 LTS in 5 Minutes appeared first on nixCraft.
2024-05-15T10:09:51Z
2024-05-15T10:09:51Z
Vivek Gite
How to use find command to delete all *.log files created in last 90 days except for last 7 days
I have log files created whenever I patch or rebuild Linux containers. They are taking disk space. The logs are helpful if something fails. Otherwise, after a few weeks, those log files have no usage for me. So here is a quick tip on how to use the find command to delete all *.log files created in the last 90 days except for the previous 7 or 10 days. The commands mentioned in these tips are compatible with the Linux, FreeBSD, and macOS versions of the find command.
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The post How to use find command to delete all *.log files created in last 90 days except for last 7 days appeared first on nixCraft.
2024-05-15T06:56:03Z
2024-05-15T06:56:03Z
Vivek Gite
How to add an IP alias to an EC2 instance on Debian/Ubuntu Linux
An IP alias on Debian, Ubuntu, or any other Linux distros refers to assigning multiple IP addresses to a single network interface. A single network interface card (NIC) can respond to multiple IP addresses and configurations. IP aliases are commonly used for various purposes, such as network segmentation, virtual hosting, load balancing, VPN, split DNS, network testing, and more. Let us see how to add IPv6 and IPv4 IP addresses to your AWS EC2 or Lightsail instance using the CLI without disturbing the IPv4/IPv6 addresses assigned by the AWS DHCP server. These instructions will also work with all other cloud providers, as most providers use DHCP to give you a public IPv4/IPv6 address.
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The post How to add an IP alias to an EC2 instance on Debian/Ubuntu Linux appeared first on nixCraft.
2024-05-14T20:43:57Z
2024-05-14T20:43:57Z
Vivek Gite
How to install dnscrypt-proxy on Debian Linux 11/12
DNSCrypt-proxy is an open-source and free software designed to encrypt DNS traffic, thus protecting it from eavesdropping and manipulation. This is also useful to evade DNS censorship when DNSCrypt-proxy is configured correctly with Wireguard or OpenVPN. Further, DNSCrypt-proxy can configured to block malware, trackers, and internet ads. In Debian 11 and 12, using DNSCrypt-proxy can enhance privacy and security by preventing DNS spoofing attacks, DNS hijacking, and surveillance of DNS traffic. It ensures that DNS queries are encrypted, authenticated, and secure, thereby safeguarding users' browsing activities and sensitive information. Let us see how to install dnscrypt-proxy on Debian Linux 11 and 12.
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The post How to install dnscrypt-proxy on Debian Linux 11/12 appeared first on nixCraft.
2024-05-13T12:23:14Z
2024-05-13T12:23:14Z
Vivek Gite
How to download a file with curl on Linux/Unix command line
I am a new macOS Unix user. I am writing a small bash shell script. How do I download file directly from the command-line interface using curl? How can I download file with cURL on a Linux or Unix-like systems?
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The post How to download a file with curl on Linux/Unix command line appeared first on nixCraft.
2024-05-12T19:41:44Z
2024-05-12T19:41:44Z
Vivek Gite
Linux/Unix: pstree Command Examples: See A Tree Of Processes
I am a new Linux user. How do I display the process on the Linux based server or desktop/laptop in easy to read tree format using bash shell prompt?
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The post Linux/Unix: pstree Command Examples: See A Tree Of Processes appeared first on nixCraft.
2024-05-12T19:29:49Z
2024-05-12T19:29:49Z
Vivek Gite