$ cat /etc/issue
$ cat /etc/redhat-release

$ cat /etc/issue
$ cat /etc/fedora-release

$ cat /etc/issue
$ cat /etc/debian_version

$ cat /etc/issue
$ cat /etc/oracle-release
$ cat /etc/redhat-release

$ cat /etc/issue
$ cat /etc/turbolinux-release

$ cat /etc/issue
$ cat /etc/SuSE-release

$ cat /etc/issue
$ cat /etc/mandriva-release

$ cat /etc/issue
$ cat /etc/vine-release

$ uname -r
$ uname -a

$ bash -version
$ rpm -q bash

$ bash -version
$ dpkg -l bash

$ bash -version
$ pacman -Q bash

$ bash -version
$ equery list bash

$ httpd -v
$ apachectl -v

$ nginx -V

$ mysql --version
$ mysqladmin --version
$ mysqladmin -u username -p'password' version

$ psql --version

$ /usr/sbin/sendmail -d0.101

$ postconf | grep mail_version

$ /usr/sbin/named -v

$ openssl version

$ /usr/bin/ssh -v

$ php -v
$ php composer.phar --version

$ perl -v
$ cpan -v
$ perldoc -v

$ python -V

$ ruby -v
$ gem -v
$ rails -v

$ git --version

$ heroku --version

$ docker version

$ packer -v

$ vagrant -v
$ vagrant --version
$ veewee version
$ vboxmanage -v

$ chef-solo -v
$ chef-client -v
$ knife --version
$ knife -v
$ berks version

$ cat cake/VERSION.txt

$ cat lib/Cake/VERSION.txt

$ cat VERSION.txt

$ php app/console --version