Global variable chapter added

.gitignore

@@ -16,3 +16,5 @@ index.tex
 /site_libs/
 /index_files/
 /docs/*
+
+**/*.quarto_ipynb

_quarto.yml

@@ -40,6 +40,8 @@ book:
          - src/configuration/initial_scripts.md
          - src/configuration/compile_time_variables.md
          - src/configuration/run_time_variables.md
+         - src/configuration/global_variables.md
+
 
       - part: "Basic Commands"
         chapters:

src/configuration/global_variables.md

@@ -0,0 +1,100 @@
+# Global Variables(`avg` Commands)
+
+Global variables are declared outside of any function or block and are accessible throughout the entire program. They persist for the full duration of execution.
+
+In reverse engineering, identifying global variables:
+
+- Improves code readability  
+- Makes cross-references easier to follow  
+- Helps with data-flow and structure analysis  
+
+**Important:**
+> In Rizin, global variables are identified during analysis.  
+> Run `aa` or `aaa` before using `avg` commands, otherwise no globals will appear.
+
+The help command to list all `avg` commands is: `avg?` 
+```
+ avgl[jqt] [<var_name>]          # show/list global variables
+ avga <var_name> <type>          # add global variable manually
+ avgd <addr>                     # delete the global variable at the addr
+ avgm <name>                     # delete global variable with name
+ avgn <old_var_name> <new_var_name> # rename the global variable
+ avgp <name>                     # print the global variable value
+ avgt <var_name> <type>          # change the global variable type
+ avgx[jq] <name>                 # print all xrefs to the global variable
+```
+
+ ``` 
+ avgl [<var_name>]       # show/list global variables
+ avglj [<var_name>]      # show/list global variables (JSON mode)
+ avglq [<var_name>]      # show/list global variables (quiet mode)
+ avglt [<var_name>]      # show/list global variables (table mode)
+ ```
+ There are 3 modes of display. Which helps in a better analysis and view the variables.
+
+ **Adding Global Variables**
+
+ `avga <var_name> <type>` This command lets you manually add global variables with their name and type.
+
+ You use then when a global variables is missed during the analysis. Here `<type>` means the datatype of the variable. Example: `int`, `char`, `long`.
+
+ This manually defines a global variable when Rizin’s automatic analysis did not detect it.
+
+ **Printing Global Variables**
+
+ `avgp <name>` reads memory at the address of the specified global variable and displays its current value.
+ >In debug mode → shows the value at the current breakpoint.
+
+ >Without debugging → shows the value stored in the binary.
+
+
+ **Changing Variable Type**
+
+ `avgt <var_name> <type>` This command lets you change the data-type of the variable.
+
+ Note: The correct data-type must be used which helps in improving output, cross-reference accuracy and structure recovery.
+
+ There are two modes of display quiet and JSON.
+
+ ### Example:
+
+ ```
+# Ran 'avglt' to check for existing global variables(none were present).
+ [0x00001040]> avglt
+ name type size address decl_file decl_line decl_col
+ ――――――――――――――――――――――――――――――――――――――――――――――――――――
+ [0x00001040]> avga test_variable int
+ [0x00001040]> avglt
+ name          type size address decl_file decl_line decl_col
+ ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
+ test_variable int   0x4  0x1040 -                -1       -1
+ [0x00001040]> avgp test_variable
+  int : 0x00001040 = 3644689736
+ [0x00001040]> avgt test_variable char
+ [0x00001040]> avgp test_variable
+  char : 0x00001040 = 'H'
+ [0x00001040]> avgn test_variable renamed_variable
+ [0x00001040]> avglt
+ name             type size address decl_file decl_line decl_col
+ ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
+ renamed_variable char  0x1  0x1040 -                -1       -1
+ [0x00001040]> avgx renamed_variable
+ [0x00001040]> avgm renamed_variable
+ [0x00001040]> avglt
+ name type size address decl_file decl_line decl_col
+ ――――――――――――――――――――――――――――――――――――――――――――――――――――
+ ```
+
+### What Was Done in This Example
+
+- Ran `avglt` to check for existing global variables (none were present).
+- Used `avga test_variable int` to manually create a new global variable of type `int`.
+- Ran `avglt` again to confirm the variable was successfully added.
+- Used `avgp test_variable` to print the value at that memory location as an `int`.
+- Changed the variable type with `avgt test_variable char`.
+- Printed the value again using `avgp test_variable`, now interpreted as a `char` (`'H'`), showing how type affects data interpretation.
+- Renamed the variable using `avgn test_variable renamed_variable`.
+- Ran `avglt` to verify the variable name and updated type were reflected.
+- Used `avgx renamed_variable` to check for cross-references (none found since it was manually added).
+- Deleted the variable using `avgm renamed_variable`.
+- Ran `avglt` one final time to confirm the global variable list was empty again.

src/refcard/intro.md

@@ -67,6 +67,8 @@ Global variables appear after auto-analysis or after adding them manually.
 | avgp name           | Print global variable     |
 | avgx name           | Show xrefs to the global  |
 
+For more info check the [global variable documentation](/src/configuration/global_variables.md).
+
 ## Information
 
 Binary files have information stored inside the headers. The `i` command uses the RzBin API and allows us to the same things rz-bin does. Those are the most common ones.