1. echo Hello, there.  Or is "hi" or "howdy" more to your liking? | egrep --color -e "Hello|hi|howdy"
Hello, there. Or is hi or howdy more to your liking?
Egrep |,+,?

grep –i “the”
echo How many sentences are here\? There are two.  No, three! | grep --color "\<[a-z]*\>[\.\?\!]“
echo 'How many sentences are here ? There are two. No, three!' | egrep --color "\<[a-z]*\> ?[\.\?\!]"
echo How many sentences are here \? There are two.  No, three! | egrep --color "\<[a-z]*\> ?[\.\?\!]“	- aici lasam si un spatiu intre cuvant si semnul de punctuatie

echo ?    - afiseaza toate fisierele din directorul curent care au un caracter
si echo *   - afiseaza toate fisierele

grep “[0-9][0-9][0-9]-[0-9][0-9]-[0-9] [0-9] [0-9] [0-9]”
        echo '045-35-2344' | grep --color '[0-9]\{3\}-[0-9]\{2\}-[0-9]\{4\}'

grep \<[a-z]\{5,}\>
6. echo How many sentences are here? There are two.  No, three! | egrep --color "\<[A-Z][^ ]*\>“
 echo How many sentences are here? There are two.  No, three! | egrep --color "\<[A-Z][a-z]*\>"
7. echo 'How many sentences are here? There are two.  No, three!'| grep --color '.*\.'
8. echo Politicians can act artificial, but do they have intelligence? | grep --color "artificial.*intelligence"
9. echo computer science is the study of computing, and how computers work.| egrep --color "comput(ers|ing|er)"
10. sed '/^$/d' faculty.details11. sed -n '/Anderson Hall/p' faculty.details 
-n nu afiseaza tot , p afiseaza doar linia cu pattern-ul
12. cat faculty.details | sed "/Perugini/a Asistent Universitar"
13. sed 's/Name: \(.*\) Office: \(.*\) Course: \(.*\)/\1:\2:\3/' faculty.details
14. sed 's/Name: \(.*\) Office: \(.*\) Course: \(.*\)/\3:\2:\1/' faculty.details 
15. sed 's/Name: \(.*\) Office: \(.*\) Course: \(.*\)/\1\n\2\n\3/' faculty.details
16. cat last.fake | grep Sun | grep economica | cut -d" " -f1 | sort | uniq	
Sort –u -> face unique	
17. cat last.fake | grep 23:|cut -f1 -d" "|sort|uniq  	(peste tot aproape cut e optional)
18. cat passwd.fake| cut -d":" -f5,3 | grep ":M" | grep "7:" 	 - daca luam cu cut doar anumite field-uri, putem cauta doar “7:”  ca restu le-am eliminat, sau cautam expresia completa: 
cat passwd.fake| grep ":M" | grep "[a-z]\{4\}[0-9]\{3\}7:"
19. cat passwd.fake| cut -d":" -f1| grep "88$"		
20. cat passwd.fake| cut -d":" -f1,3| grep ":23[0-9]:" | cut -d":" -f1		
21. sed 's/\([aeiou]\)/\1\1/g' ps.fake
22. cat passwd.fake | sed "s/[ a-zA-Z]//g“ | sort | uniq	
23. cat passwd.fake | sed "s/[^r]//g" | sort | uniq
24. cat ps.fake| sed "s/\s\s*/ /g"|cut -d" " -f2 | sed "/^$/d" | sed "/PID/d" > pid.txt     -> pid contine si alte chestii
Dar daca zicem:   cat ps.fake| sed "s/\s\s*/ /g"|cut -d" " -f2 |grep "^[0-9]" > pid.txt   (atunci pare ok)


#!/bin/sh
pids=`cat pid.txt`
sum=0
n=0
for x in $pids
do
sum=`expr $sum + $x`
n=`expr $n + 1`
done
echo $sum $n
medie=`expr $sum / $n`
echo $medie