3. - Getting and saving data

      
•        for entering data points from the keyboard, from files or with a digitizer       
•        for saving data to files       
•        for modifying data using the interactive editor       
•        for entering and using error-bar information

3.1. - Commands covered
3.2. - gd get data
3.3. - sa save current data
3.4. - eb select error-bar mode