head is also an ancient and justified UNIX command. Its syntax is typically
head -10 wazoo
head -n 10 wazoo
head -c 1024 wazoo
head -1k wazoo
The first two examples print the first 10 lines in the wazoo file. The third and the fourth print the first kilobyte in the file.
Notice that head, like most UNIX utilities, knows nothing about the content and structure of your file.
This example refers to GNU head, although the first example probably works with any implementation.
head's best buddy are tail, wc, nl, and cut.