Metatrader is a platform/software for windows for tradeing in forex i.e. foreign exchange market commodity like gold and silver. It has all features a beginner wants. You can do Fibonacci extensions , retracements, and other patterns. Also you can use various oscillator in them. Graphing facility is inbuilt. It is offered by nearly all major brokerages,. It can also be utilized for determining trends like Bollinger bands, Moving average, SAR, standard deviation. You can also use all three type of charts: bar, line and candlesticks.

You can use many freely and commercially available expert advisers with it.
But still many professional found faults with it so Meta quotes decided to upgrade their version and include various features( multiasset backtester, option trading , event-based programming). MQL 5 is currently in beta stage.
Of course some of the features of MQL have also been updated. But if you know old version you can easily get settled . Of course , Metatrader AutoTrading Championships.
You can use wine or crossoverlinux. to run it on Linux .