regex: Using notepad++

Goal: Learn and practice regex

. : zero or one character

[wildcards]
. : any character (t.p matches tip, top, tap...)
* : zero or more times (.* matches all letter in 'tip')
? : zero or one time (tips? matches 'tip' or 'tips' - with s or without s)
+ : one or more times (tip.+ matches tips but not tip)
x|y : x or y (tip|top match both tip or top)
\ : escape any special character (where\? matches where?
[Anchors]
^ : start of a string (^T matches 'This is an example.')
$ : end of a string ($s matches 'There are many users')
[Groups]
[x|X] : matches either x or X ([C|c]at matches Cat or cat)
{n} : matches n number of times (.{3} matches The in There - 3 characters)

Real life example: Each line, remove everything except e-mail address

Line 1: era@gmail.com
Line 22: zeo0326@gmail.com
Line 39: ro97xu@gmail.com
Line 95: zeroday224@gmail.com
Line 1002: dhs@gmail.com
Line 50044: aint@gmail.com
Line 61345: se7en@gmail.com
Line 7893465: tn@gmail.com

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Dùng tính năng tìm kiếm và thay thế (Ctrl + H)
PHẢI chọn Regular expression trong phần Search Mode

Find what: "^.*(\<[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z][A-Za-z][A-Za-z]?[A-Za-z]?\>).*$" (không nhập dấu nháy kép)
Replace with: \1

Thử nghiệm trước để kiểm tra:
Nhấn Find và Find Next vài lần để xem có tìm đúng nội dung cần xóa không.

Nhấn Replace All

Commonly used "patterns" in search/replace

- Email address: [A-Z0-9._%+-]+@[A-Z0-9.-]{3,65}\.[A-Z]{2,4}
- Search for emails ending with .vn or .com: [^\.vn][^\.com]$

Example: "${Keep everything inside}"

Search: "\$\{(.*[^{"\}])\}\"

Replace: \1

provider "oci" {
  region           = "${var.region}"
  tenancy_ocid     = "${var.tenancy_ocid}"
  user_ocid        = "${var.user_ocid}"
  fingerprint      = "${var.fingerprint}"
  private_key_path = "${var.private_key_path}"
}