1) Try this on the command line and explain what it is doing: grep hom.*ds p* [1]

2) Print all lines containing one non-digit

3) Print all lines containing digits followed by a space and a capital letter

4) Print all lines containing an s followed by zero or more consecutive occurrences of the letter s and a space.

5) Print all lines containing at least nine consecutive lowercase letters (i.e. northeast)

6) Print all lines containing a word starting with a lowercase letter and followed by any number of characters and ending with t

7) Print all lines containing the number 4 followed by a comma , and any single character

Can use this text to test:

How many people have ever lived on earth?

It was written during the 1970s that 75% of the people who had ever been born were alive at that moment. This was grossly false. Assuming that we start counting from about 50,000 B.C., the time when modern Homo sapiens appeared on the earth (and not from 700,000 B.C. when the ancestors of Homo sapiens appeared, or several million years ago when hominids were present), taking into account that all population data are a rough estimate, and assuming a constant growth rate applied to each period up to modern times, it has been estimated that a total of approximately 106 billion people have been born since the dawn of the human species, making the population currently alive roughly 6% of all people who have ever lived on planet Earth.

Others have estimated the number of human beings who have ever lived to be anywhere from 45 billion to 125 billion, with most estimates falling into the range of 90 to 110 billion humans.

Top 20 Largest Countries by Population today (live) 1 China 1,401,121,647 2 India 1,281,110,640 3 United States 324,848,474 4 Indonesia 255,457,959 5 Brazil 203,529,872 6 Pakistan 187,829,474 7 Nigeria 182,985,378 8 Bangladesh 160,235,085 9 Russia 142,143,395 10 Japan 126,872,277 11 Mexico 125,116,488 12 Philippines 101,633,384 13 Ethiopia 98,693,409 14 Vietnam 93,325,835 15 Egypt 84,586,172 16 Germany 82,586,271 17 Iran 79,390,019 18 Turkey 76,649,256 19 Congo 71,042,049 20 Thailand