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Showing posts from March, 2018

centos change ssh port

in this tutorial, How to change ssh port another with selinux. The default ssh port 22, when you change port another with rules selinux (SELINUX=enforcing) get error can't change ssh port. Solve problem!( Running command following with root account) File selinux with content SELINUX=enforcing as below: [huupv@huupv ~]$ sudo cat /etc/sysconfig/selinux [sudo] password for huupv: # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: #     enforcing - SELinux security policy is enforced. #     permissive - SELinux prints warnings instead of enforcing. #     disabled - No SELinux policy is loaded. SELINUX=enforcing # SELINUXTYPE= can take one of these three values: #     targeted - Targeted processes are protected, #     minimum - Modification of targeted policy. Only selected processes are protected. #     mls...

Centos 7 managing services with Systemd

Centos 7 managing services with Systemd. -List all the current loaded targets as command below: $ sudo systemctl list-units -t target Each services has 3 states; enabled, disabled and static. - To list enabled services as command below: $ sudo systemctl list-unit-files --type=service | grep enabled - To start/stop/restart services as command below: # systemctl status <servicename> # systemctl stop <servicename> # systemctl start <servicename> # systemctl restart <servicename> - To check running ntp services as comman below: $ sudo systemctl list-units --type service --all | grep ntp - Set the service to start a boot: # systemctl enable <servicename> - Disable service start-up boot # systemctl disable service The update later related command line "Centos 7 managing services with Systemd" in this article.

How to Use Bash script Change folder Permissions Recursively

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Introduction Learn how to use a bash script to change folder permissions recursively with practical examples. This guide includes step-by-step instructions and script samples to effectively manage file permissions in Linux. Managing file permissions is a fundamental task for any system administrator. Often, you need to change the permissions of a directory and all its contents. This guide will demonstrate how to use a bash script to change folder permissions recursively, with examples covering both basic and advanced scenarios. What is Recursive Permission Change? Recursive permission change applies the specified permissions to the target directory and all its subdirectories and files. This approach is particularly useful for ensuring consistent access controls across complex directory structures. Why Use Bash Scripts for Permission Changes? Bash scripts allow for automation, saving time and reducing errors when changing permissions across multiple files and directories. Scripts can b...

List the contents of tar gz file

tar command is archiving utility. Something, you can retrieve extension .tar.gz or .tar.bz2 file. How to list the contents this without extracting from command line. The syntax tar command as below: tar OPTION File_Name With OPTION : t, --list : List the contents of an archive v : Verbosely list files processed j : Filter archive through bzip2 f : filename  You may reading link as below: Iptables how to How to reset password on centos 7 Bash script example List the contents of .tar.gz file To use tar command for .tar.gz as following: $ tar -tvf links-2.12.tar.gz  The output of links-2.12.tar.gz file as below: -rwxr--r-- 1000/1000      1215 2001-10-05 14:03 links-2.12/mailcap.pl -rwxr-xr-- 1000/1000      4654 2015-06-28 22:13 links-2.12/rebuild -rw-r--r-- 1000/1000       461 2003-05-06 01:10 links-2.12/links_16x16_1.xpm -rw-r--r-- 1000/1000      2410 2003-05-...

How to List top sender address emails in zimbra from the Command Line

Introduction Zimbra is a widely-used email platform, offering robust features for managing emails within organizations of all sizes. Understanding who the top email senders are within your Zimbra system can be crucial for various reasons, such as monitoring email traffic, identifying potential spam sources, and optimizing your email server's performance. In this guide, we will walk you through the process of listing the top sender email addresses in Zimbra using command-line tools. By the end of this article, you'll have a clear understanding of the commands needed to identify the top senders and how to interpret the results to improve your email management practices. Step-by-Step Guide to Listing Top Sender Email Addresses Step 1: Access the Zimbra MTA Server To begin, you need to access the Zimbra Mail Transfer Agent (MTA) server, where Zimbra's log files are stored. These log files contain detailed records of all email transactions processed by your Zimbra system. How t...