Linux – nixCraft

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

June 23, 2014June 23, 2014in Amazon Cloud Computing, CentOS, Linux, Openbsd, RedHat and Friends, UNIX last updated June 23, 2014

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?

Linux: Jpeg Image Optimization / Compress Command

April 9, 2013September 23, 2013in Amazon Cloud Computing, Linux, UNIX last updated September 23, 2013

I know how to optimize and compress png images using optipng command. line tool. I have lots of images in JPEG format. How do I compress and optimize JPEG images on my amazon cloud account so that I can save bandwidth on cloudfront cdn account? How do I use an image compressor to create lossless compression on JPEG files, with no effect on image quality in bulk using Linux?

gnome-terminal: There Was An Error Creating The Child Process For This Terminal

December 4, 2012December 4, 2012in CentOS, RedHat and Friends, Troubleshooting last updated December 4, 2012

I am using CentOS 5 on my laptop. If I open gnome-terminal by right clicking the desktop, I am getting an error that read as follows:

There was an error creating the child process for this terminal

How do I fix this problem and open a terminal by right clicking the Debian / Ubuntu / CentOS / Fedora / RHEL / Red hat Enterprise Linux 5.x desktop system?

Linux / Unix: Unicode and HTML Characters Lookup By Name or Number

December 4, 2012December 4, 2012in Gnome, kde, Perl last updated December 4, 2012

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?

Linux / Unix: Rsync Copy Files & Directories Names With WhiteSpaces and Blanks

November 28, 2012January 31, 2015in BASH Shell, CentOS, Debian / Ubuntu, FreeBSD, Linux, Suse, Ubuntu Linux, UNIX last updated January 31, 2015

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?

Linux / Unix vi / vim: Open and Switch Between Multiple Files

November 20, 2012October 18, 2015in CentOS, Debian / Ubuntu, FreeBSD, Linux, RedHat and Friends, Suse, UNIX, Vim last updated October 18, 2015

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?

RHN yum command: Unable to read consumer identity Warning and Solution

November 17, 2012in RedHat and Friends, Troubleshooting last updated November 17, 2012

I am using yum update command with RHN to upgrade packages installed on my server, but getting the following warning on screen :

yum update -y Loaded plugins: product-id, protectbase, rhnplugin, security, subscription manager: Updating certificate-based repositories. Unable to read consumer identity 0 packages excluded due to repository protections Setting up Update Process Resolving Dependencies --> Running transaction check ...&ltsnip>

How do I get rid of this warning /error under RHEL 6 server?