Openbsd – nixCraft

How to summarize detailed system resource usage for given command on a Linux or Unix

December 8, 2015December 8, 2015in CentOS, Debian / Ubuntu, FreeBSD, Linux, Mac OS X, Troubleshooting, UNIX last updated December 8, 2015

How do I determine the system resource usage during of execution of a particular command on a Linux, OS X Unix, BSD and Unix-like operating system?

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?

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

May 10, 2013May 10, 2013in BASH Shell, Commands, Linux, UNIX last updated May 10, 2013

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?

Vi / Vim: Wipe and Undo All Changes Since Opening a File

April 28, 2013April 28, 2013in Linux, UNIX, Vim last updated April 28, 2013

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?

SSH: WARNING: UNPROTECTED PRIVATE KEY FILE! Error and Solution

April 9, 2013January 26, 2017in Amazon Cloud Computing, Linux, Mac OS X, Openbsd, Suse, Troubleshooting, UNIX last updated January 26, 2017

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 [email protected]

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?

Linux / Unix Bash Shell List All Builtin Commands

March 19, 2013in BASH Shell, Linux, UNIX last updated March 19, 2013

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?

Linux / Unix Find Command: Avoid Permission Denied Messages

March 10, 2013March 10, 2013in BASH Shell, Linux, Troubleshooting, UNIX last updated March 10, 2013

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?