Brace expansion

❯ echo {1,2,3}
1 2 3

# Spaces are not allowed
echo {1, 2, 3}
zsh: parse error near `}'

❯ echo file{1,2,3}
file1 file2 file3

❯ echo file{,2,3}
file file2 file3

❯ echo file{1..3}
file1 file2 file3

❯ echo file{001..3}
file001 file002 file003

# Nested
❯ echo file{1,2{a,b},3}
file1 file2a file2b file3

❯ mkdir -p settings/{__init__,base,local}
 
❯ tree
.
└── settings
    ├── __init__
    ├── base
    └── local

❯ mkdir -p parent/{girl,boy}/{name,age}
 
❯ tree
.
└── parent
    ├── boy
    │   ├── age
    │   └── name
    └── girl
        ├── age
        └── name

❯ touch 11.{in,py}
 
❯ tree
.
├── 11.in
└── 11.py

❯ touch post_2022_{01..3}.md
 
❯ tree
.
├── post_2022_01.md
├── post_2022_02.md
└── post_2022-03.md

❯ touch test.js
 
❯ cp test{,_copy}.js
 
❯ tree
.
├── test.js
└── test_copy.js

❯ touch test.txt
 
❯ mv test.{txt,md}
 
❯ tree
.
└── test.md

❯ mv {,parent/}folder
 
❯ tree
.
└── parent
    └── folder

❯ curl https://httpstat.us/{417..418}
417 Expectation Failed418 I'm a teapot%