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scp: Do not Overwrite Existing File On Linux or Unix System

I am a new Linux user. I use scp to upload files to net-storage provided CDN company. I do not want to overwrite the existing files. How can I prevent overwriting of files when using scp command under Linux, Mac OS X or Unix like operating systems?
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Vi / Vim: Wipe and Undo All Changes Since Opening a File

I am a new vi / vim text editor user and I know how to quit without saving changes. What if I want to wipe out all of the edits I have made in a session and get back to the original file? How do I wipe all changes since opening a file?
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Linux / Unix: Use rsync Command Over FTP

How do I use rsync command to sync files to a remote host called web-42.vps running VSFTPD ftp server? Can you give me rsync ftp example for Unix like operating systems?
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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:
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

How do I fix this problem and login using ssh command?
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Linux / Unix Bash Shell List All Builtin Commands

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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Linux / Unix Find Command: Avoid Permission Denied Messages

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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Linux: See Bandwidth Usage Per Process With Nethogs Tool

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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HowTo: Firefox Disable Default PDF Viewer / Plugin

I recently updated my Mozilla Firefox. Firefox now includes a built-in PDF viewer that allows me to see PDF files found on the web without a plugin. The built-in PDF viewer is enabled by default. However, I found that this pdf viewer is not working properly with various web-sites, and it works slowly. How do disable the built-in PDF viewer so that I can use the Adobe PDF viewer or other PDF viewer that is shipped with my operating systems?
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