Update readme

README.md

@@ -10,7 +10,39 @@ Usage of ./passwgen-go:
   -m, --min=8: Minimum size of the password
 ```
 
-This is a simple CLI random password generator written in go. It generates passwords given the type of characters and the intended password size.
+This is a simple CLI random password generator written in golang. It generates the password given the type of characters and the intended password size.
+
+# Installation
+
+## Download executable
+
+Binary releases are available in [here](https://github.com/Bollos00/passwgen-go/releases) for different platforms, so you can just download and run it.
+
+## Building from source code
+
+It is also possible to build it from the source code if you have [go](https://go.dev/dl/) and git installed on your system. To do so, follow those steps:
+
+```
+$ git clone https://github.com/Bollos00/passwgen-go.git
+$ cd passwgen-go
+```
+
+To install:
+```
+$ go install .
+```
+
+To just build it:
+```
+$ go build .
+```
+
+To run it:
+```
+$ go run ./main.go
+```
+
+# Usage
 
 ## Types of characters
 
@@ -23,3 +55,42 @@ There are four types of characters shown in the table bellow.
 | Upper Letter | `'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'`|
 | Special      | <code>'!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+', ',', '-', '.', '/', ':', ';', '<', '=', '>', '?', '@', '[', '\\', ']', '^', '_', '\`', '{', '\|', '}', '~', ' '</code> |
 
+By default it will use all of them, but you can change it passing the `-c` a and `-i` parameters to the program. Examples:
+
+* Generates a password with only numerical characters
+```
+$ passwgen-go -c "0"
+```
+
+* Generates a password with only lower and upper letter characters
+```
+$ passwgen-go -c "aA"
+```
+
+* Generates a password with numeral, lower and upper letter characters but ignoring 01oOil
+```
+$ passwgen-go -c "gH5" -i "01oOil"
+```
+
+* Generates a password only with special characters
+```
+$ passwgen-go -c "@"
+```
+
+## Password size
+It is also possible to set the desired length of the password, being it a fixed value or a number between a range with the `-m`, `-M` and `-l` flags. By default it generates a password with a length between 8 nad 16. Examples:
+
+* Generates a password with length between 20 and 30
+```
+$ passwgen-go -m 20 -M 30
+```
+
+* Generates a password with fixed length of 50
+```
+$ passwgen-go -l 50
+```
+
+* Generates a password with fixed length of 6 with only numbers
+```
+$ passwgen-go -l 6 -c "1"
+```