Auyez Zhumashev
Alisher Shakhiyev

1. It outputs number between 1 and 10000 that satisfies all three conditions (nr % 5 == 3 && nr % 7 == 4 && nr % 9 == 5).

	#!/bin/bash

	MAX=10000 # declare constant 10000

	for((nr=1; nr<$MAX; nr++)) # for loop from 1 to 10000
	do # start of the loop body

		let "t1 = nr % 5" # calculate nr mod 5 and assign it to vatiable t1
		let "t2 = nr % 7" # calculate nr mod 7 and assign it to vatiable t1
		let "t3 = nr % 9" # calculate nr mod 9 and assign it to vatiable t1

		#check if t1 == 3 && t2 == 4 && t3 == 5
		if [ "$t1" -eq 3 ] && [ "$t2" -eq 4 ] && [ "$t3" -eq 5 ]
		then
			break #break if number found
		fi
	done #finish loop

	echo "Number = $nr" #print the number
	exit 0 #successfully exit the program


2. 1)This program lists all files in DIRNAME with their filetypes
   2)finds only those with filetype == FILETYPE
   3)writes them into logfile
   4)outputs the number of scripts


3. This script first searches for all java files in "src" directory. Then it takes the second line from each of the files and stores it in the SUM variable. At the end it prints out the result (SUM variable).

#---------------SCRIPTS---------------#


[Self-reproducing Script]
----------------------------------
1) #!/bin/bash
scriptname=$(basename "$0")
cat $scriptname >> backup.sh
exit 0

2) #!/bin/bash
scriptname=$(basename "$0")
cat $scriptname » backup.sh
for ((i=1; i<$(($#+1)); i++))
do
eval arg=\$$i # adapted from stackoverflow
cat $arg » $arg.backup
done
exit 0
----------------------------------


[While and Until loops]
----------------------------------
#!/bin/bash

array=( Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto )
n=0
limit=9
while [ "$n" -lt "$limit" ]
do
	echo ${array[n]}
	(( n=n+1 ))
done
exit
-----------------
#!/bin/bash

array=( Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto )
n=0
limit=9
until [ "$n" -eq "$limit" ]
do
	echo ${array[n]}
	(( n=n+1 ))
done
exit
----------------------------------

NOTE: During analyzing first three tasks, we used google to understand the syntax.