Both ends of the 26-line fixture, including the plus form

Answer

head roster.txt head -3 roster.txt tail roster.txt tail -3 roster.txt tail -n +20 roster.txt

Lines 1-10, then 1-3, then 17-26, then 24-26, then 20-26. The last one is the plus form: from line 20 onward, not the last 20.

S&K 3e ch6 §6.2