The young shoots up to 6 inches tall can be eaten raw and the starchy base (usually white and at the bottom when you pluck it) can be eaten as a trail nibble. The more mature the grass plant gets, the more fibrous the plant becomes.
The best part of the grass plant to eat are the seed heads, which can be gathered to make millet for breads or filler for soups & stews. Of the 99% that can be eaten raw, about 1% have toxic seeds and require that you roast or cook the seeds first. As a word of caution, stay away from blackish or purple colored grass seeds. This is a good indication of toxic fungus.
While food is often touted to not be a major priority in a survival situation, you should try building a shelter on an empty stomach and see how quickly your tune changes.
It won’t be a steak dinner, but the additional edible plants on the next slide could very well save your life.
For starters learn about a tree that provides a great source of food in the fall and early winter time. The food from this tree can help you stay alive when you're running low on your food supply!