Understanding Linux File Permissions and Ownership

The Linux permissions are composed of 9 bits, which are assigned to files and folders and it appears as -rwxrwxrwx. Note: For a regular file a dash appears right in front of the 9-bits, however if it is a directory then you will see a d right in front of it instead of a dash, this is to indicate that it is a directory. E.g. l for (symbolic link) b for (block device)

Installing Python From Source

Getting the Python release First we need to go to Python's source download link at and choose our Python version, for this tutorial I have chosen Python 3.5.2 as it's the latest stable release as of this writing. wget or directory specific: wget -P /tmp The above command will download python 3.5.2 Gzipped source tarball to the current directory I'm currently in /root, you can specify -P as specified above to save on that directory.

Installing Postgresql Centos 7

You can check which version of Centos you are running by: cat /etc/redhat-release Output CentOS Linux release 7.2.1511 (Core) Install the repository for the latest stable version: Add "exclude=postgresql*" to code blocks [base] and [updates] sections in /etc/yum.repos.d/CentOS-Base.repo to avoid outdated yum packages. Then Install the latest version repo RPMs for Centos 7. Get the link for the latest stable version at yum localinstall <link from the comment above> As of this writing version PostgreSQL 9.

Zipping and Unzipping Files Linux

Linux has a Zip and Unzip program, which allows you to compress or decompress files, however most distributions does not come with it installed by default. You can install this programs with the Shell prompt. Open Application > System Tools > Terminal. Type the following command to install on Debian based operating systems like, Ubuntu, Mint and so on: apt-get install zip apt-get install unzip or sudo apt-get install zip unzip If you are on RedHat based operating systems like CentOS:

Fix Authentication refused bad ownership or modes ssh

If you are setting a server or your own machine with SSH key password-less, then you will likely get this error Authentication refused bad ownership or modes. This happens for your own security, SSH is very picky when dealing with ~/.ssh and this is the right thing, people apart from yourself should not be able to move, read or edit your ~/.ssh. To fix this issue all you have to do is set the right permission.