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UNIX

Connect To Amazon AWS EC2 Instance From a CentOS / RHEL Using SSH Client

I have created/launched Amazon Machine Image (AMI) instance powered by a CentOS/RHEL/Red Hat Enterprise Linux. How can I connect to my instance using OpenSSH Linux/Unix/OSX ssh client?
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MySQL/MariaDB Server: Bind To Multiple IP Address

I have MySQL/MariaDB database system running on a FreeBSD/Linux server. The server has multiple ip address. The mysqld used by many websites hosted on two other CentOS Linux based servers. I would like to bind MySQL sever running on a Linux or Unix-like server to more than one IP address such as 202.54.1.2, 202.54.1.10, and 202.54.1.15. How can I bind mysqld to multiple ips?
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Linux / Unix: Unicode and HTML Characters Lookup By Name or Number

I need to replace special characters with equivalent hexadecimal unicode under Linux or Unix like operating system. How do I list or find out unicodes for given characters?
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Linux / Unix: Rsync Copy Files & Directories Names With WhiteSpaces and Blanks

I need to transfer a file called 'some cool movie.avi' that contains whitespace under rsync. How do I escape a filename or directory name with spaces in them while using rsync command under Linux / *BSD / Unix like operating systems? How do I use rsync when files / dirs contain spaces?
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Linux / Unix vi / vim: Open and Switch Between Multiple Files

I am new to Linux sysadmin work. I am using vi / vim text editor to edit files located in /etc/ directory. I open files using

vi /etc/resolv.conf /etc/hosts

I can edit the /etc/resolv.conf file only. How do I switch between the two open files while using vim text editor under Linux / BSD / Apple OS X / Unix like operating systems?
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Linux / Unix: Sed / Grep / Awk Print Lines If It Got 3 Words Only

I have a sample data file:


This is a test.
Unix is Best.
No Linux is the Best.
Space in simple understanding is an area or volume.
Outer space .

I need the output:

Unix is Best.
Outer space .


How do I print all lines that have three (3) words only?
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Linux / Unix: Rsync Copy Hidden Dot Files and Directories Only

How do I use the rsync tool to copy only the hidden files and directory (such as ~/.ssh/, ~/.foo, and so on) from /home/jobs directory to the /mnt/usb directory under Unix like operating system?
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Bash Check If Shell Is Interactive or Not Under Linux / Unix Oses

How do I check in GNU/Bash if a shell is running in interactive mode or not while writing shell scripts?
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Grep Include Only *.txt File Pattern When Running Recursive Mode

I'm using Debian Linux as my development workstation. I would like to search a directory called ~/projects/ recursively for "foo" word only for *.txt files. How do I search all text files in ~/projects/ for "foo" word using grep command?
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Linux dd Command Show Progress Copy Bar With Status

I'm using dd command for block level copy and just found out that there's no built in way to check the progress. How do I use the Linux or Unix dd command while coping /dev/sda to /deb/sdb and display a progress bar when data goes through a pipe?
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