Usefull Transaction Code in Abap

SE38 - Abap Editor.
SA38 - Execute a program.
SE11 - ABAP/4 Dictionary.
SE10 - Customizing Organizer (Transport).

SE71 -	SAPscript layout set
SE71 -	SAPscript Layouts Create/Change
SE72 -	SAPscript styles
SE73 -	SAPscript font maintenance (revised)
SE74 -	SAPscript format conversion
SE75 -	SAPscript Settings
SE76 -	SAPscript Translation Layout Sets
SE77 -	SAPscript Translation Styles
SE80 -	ABAP/4 Development Workbench
SE80 -	Repository Browser: Initial Screen.
SE81 -	SAP Application Hierarchy
SE82 -	Customer Application Hierarchy
SE84 -	ABAP/4 Repository Information System
SE85 -	ABAP/4 Dictionary Information System
SE86 -	ABAP/4 Repository Information System
SE87 -	Data Modeler Information System
SE88 -	Development Coordination Info System
SE91 -	Maintain Messages
SE92 -	Maintain system log messages
SE93 -	Maintain Transaction Codes

What is Abap?

ABAP - Advanced Business Application Programming

ABAP is a programming language for developing applications for the SAP R3 system, a widely-installed business application subsystem. ABAP is the Fourth generation programming language developed by SAP AG to develop application programs. The latest version, ABAP Objects, is object oriented programming. SAP will run applications written using ABAP/4, the earlier ABAP version, as well as applications using ABAP Objects.