EXPONENTIATION
let "y=2**4"
echo $y
16
GENERATE A SEQUENCE OF NUMBERS - INCREMENTAL ORDER
for i in $(seq 1 4);do echo $i;done;
OR
for ((i=1;i<=4;i++));do echo $i;done;
1
2
3
4
GENERATE A SEQUENCE OF NUMBERS - DECREMENTAL ORDER
for i in $(seq 4 -1 1);do echo $i;done;
OR
for ((i=4;i>=1;i--));do echo $i;done;
4
3
2
1
CONCATENATE STRING WITH +=
s="hello"
s+=", world"
echo $s
hello, world
EXTRACT SUBSTRING
## syntax ##
#${parameter:offset:length}
string="abcdefghi"
echo ${string:0:5}
abcde