add guide for pre and postrun

website/docs/guide/prepostrun.md

@@ -0,0 +1,42 @@
+---
+title: "Pre/Post run"
+date: 2023-09-23T16:15:09+08:00
+draft: false
+weight: 100
+chapter: false
+---
+
+The PreRun and PostRun methods allow you to specify custom functions that should be executed before and after running a command, respectively. These functions can be used for tasks such as setup, cleanup, or any other actions you want to perform before or after executing a command.
+
+PreRun
+
+The PreRun method is used to specify a function that should run before executing a command. The function you pass to PreRun takes a *Cli parameter, which represents the CLI application itself. You can use this function to perform any necessary setup or validation before running the command.
+
+PostRun
+The PostRun method is used to specify a function that should run after executing a command. Similar to PreRun, the function you pass to PostRun takes a *Cli parameter. You can use this function to perform any cleanup or post-processing tasks after the command execution.
+
+Example of postRun
+```go
+func main() {
+    cli := clir.NewCli("MyApp", "My CLI application")
+
+    // Define a command
+    cmd := cli.NewSubCommand("mycommand", "Description of mycommand")
+
+    // Add flags, actions, and other configurations for the command
+
+    // Define a PostRun function for the command
+    cmd.PostRun(func(c *clir.Cli) error {
+        // Perform cleanup or post-processing here
+        fmt.Println("Running PostRun for 'mycommand'")
+        return nil // Return an error if something goes wrong
+    })
+
+    // Run the CLI application
+    if err := cli.Run(os.Args[1:]...); err != nil {
+        fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+        os.Exit(1)
+    }
+}
+
+```