A beginners guide to programming and automating stuff

RHCE – The getent command

The getent command essentially queries a collection of sources to return a comprehensive list. $ get passwd root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt mail:x:8:12:mail:/var/spool/mail:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin games:x:12:100:games:/usr/games:/sbin/nologin ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin systemd-bus-proxy:x:999:998:systemd Bus Proxy:/:/sbin/nologin systemd-network:x:998:997:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:997:996:User for polkitd:/:/sbin/nologin sssd:x:996:995:User for sssd:/:/sbin/nologin abrt:x:173:173::/etc/abrt:/sbin/nologin . . …etc . . . Read more

Python – Pip To install python on centos: $ yum install python-pip Some useful commands: $ pip list # equivalent to: yum list aailable … $ pip show {packagename} # equivalent to: yum info …. $ pip search {keyworld} # equivalent to: yum search …. # equivalent to In Ruby, . . . Read more

Python – Virtualenv

Virtualenv is the ruby equialent of ruby’s rbm. To start using Virtualenv, you need to run the following as the root user: $ yum install python-pip $ pip install virtualenv $ pip install virtualenvwrapper # optional but provides the workon From this point forward you can run all other commands . . . Read more

Python – crash course

To install python: $ yum install python indentation is important, since code blocks are not encased in any brackets whatsoever. to access python command line (aka repl) do: [root@ansibleclient01 ~]# python Python 2.7.5 (default, Nov 20 2015, 02:00:19) [GCC 4.8.5 20150623 (Red Hat 4.8.5-4)] on linux2 Type “help”, “copyright”, “credits” . . . Read more

AWS – CloudHSM

CloudHSM (Hardware Security Module): This is essentially the name of a dedicated physical machine that is seperate from all the other AWS hardware, and it is used to store encryption keys. If an outside party gains access to these keys, then your AWS infrastructure is compromised. Hence even AWS employees . . . Read more

AWS – Cloudwatch related security features

Cloudwatch related API requests are signed with HMAC-SHA1signature from the request and the the user’s private key Cloudwatch’s (sdk) API is only accessible via https, not http, i.e. it is encrypted with ssl An IAM user can only access cloudwatch if they are given access via IAM You can configure . . . Read more