outputs text over and over.
If you need a file of some size for testing, make it with yes
For example, to make a file 100k (102,400) characters long,
with 12,800 8-character lines (7 digits and a newline), type:
yes 1234567 | head -12800 > 100k-file
On some UNIX systems, that command may "hang" and need to be killed with
CTRL-c - because head
keeps reading input from the pipe.
If it hangs on your system, replace