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CentOS Howtos and Tutorials

Centos Linux tutorial for beginners and advanced users with special focus on security, firewall, web, mail, file and proxy servers in an enterprise environment (rss feed).

I'm setting up server on an Amazon EC2 compute instance powered by Suse Enterprise Linux server. I am using the following command to login into the my EC2 compute from OS X/Ubuntu desktop:

ssh -i suse-ec2-server-jp.pem root@ec2-xx-yy-zzz-yyy.compute-1.amazonaws.com

I am getting the following error:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: UNPROTECTED PRIVATE KEY FILE! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0440 for 'suse-ec2-server-jp.pem' are too open.
It is recommended that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: suse-ec2-server-jp.pem
Password:

How do I fix this problem and login using ssh command?
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Builtin commands are contained within the bash shell itself. How do I list all bash builtin commands under Linux / Apple OS X / *BSD / Unix like operating systems without reading large bash man page?
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Linux: Start Command In Background

I am a new Linux command line user. How do I start or run command in the background so that I can access command prompt immediately?
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I have Debian / Ubuntu Linux. I need to compile software written in C. The gcc throwing an error that read as follows:

gnu/stubs-32.h: No such file or directory compilation terminated. make: *** [foo.o] Error 1

How do I fix this problem under Debian or Ubuntu Linux 64 bit system and compile apps using gcc compiler?
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When I type find . -type d -name "foo" command I get Permission denied error messages. How do I exclude all "permission denied: messages from the find command under Linux or Unix like operating systems?
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HowTo: Use pwd Command In Linux / UNIX

How do I use the pwd command in Linux or Unix like operating systems? How can I use pwd command in UNIX or Linux shell scripts for automation purpose?
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I have Red Hat Enterprise Linux 6.x server. How do I find out and groups network bandwidth usage by process under Linux operating systems? How do I find out what programs are using network bandwidth under Linux operating systems? How can I see bandwidth usage per PID, command, and user on a Linux operating systems?
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