Bash Brace Expansion

$ echo {0..9}
0 1 2 3 4 5 6 7 8 9

$ echo b{a,e,i,o,u}
ba be bi bo bu

$ echo x{0..9}y
x0y x1y x2y x3y x4y x5y x6y x7y x8y x9y

$ echo {a..z}
a b c d e f g h i j k l m n o p q r s t u v w x y z

$ echo {1..3} {A..C}
1 2 3 A B C

$ echo {1..3}{A..C}
1A 1B 1C 2A 2B 2C 3A 3B 3C

echo {a,b{1,2,3},c}
a b1 b2 b3 c

$ mkdir -p {project1,project2}/{src,tst,bin,lib}/
$ find .
.
./project1
./project1/tst
./project1/bin
./project1/lib
./project1/src
./project2
./project2/tst
./project2/bin
./project2/lib
./project2/src

$ echo {{A..Z},{a..z}}
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z

$ for i in {a..f} 1 2 {3..5} ; do echo $i;done
a
b
c
d
e
f
1
2
3
4
5

The examples below requires Bash version 4.0 or greater.

$echo {001..9}
001 002 003 004 005 006 007 008 009

$ echo {1..10..2}
1 3 5 7 9