Reading parts of raw data files
If you have a big file it will take SAS some time to work through it all. If you are still debugging your code, this processing of the full data file is a waste of time. It uses up machine resources that others could utilize (it slows down the work of others). It makes it so that you get less jobs run in a day too.
Use the OBS= and/or FIRSTOBS= options of the INFILE statement at the early stages of debugging.
To read just the first 100 observations:

	INFILE BIGFILE OBS=100;

To skip just the first 100 observations:

	INFILE BIGFILE FIRSTOBS=101;

To read from the middle:

	INFILE BIGFILE FIRSTOBS=101 OBS=200;

For more, see example 14.