What impact does the SIGHUP signal have on a running process in the system?

The SIGHUP (Signal Hang UP) signal was originally sent to a terminal when the connection was lost (for example, when closing the terminal). For a process, this means that the controlling terminal was disconnected.

In modern systems, SIGHUP is often used for:

• Reloading a process's configuration without stopping it.
• Terminating a process (if it does not handle the signal).

In Go, you can catch this signal using the os/signal package and perform necessary actions, such as reloading settings:

import (
    "os"
    "os/signal"
    "syscall"
    "fmt"
)

func main() {
    sigs := make(chan os.Signal, 1)
    signal.Notify(sigs, syscall.SIGHUP)

    go func() {
        for {
            sig := <-sigs
            if sig == syscall.SIGHUP {
                fmt.Println("Received SIGHUP: reloading configuration")
                // Reload logic here
            }
        }
    }()

    // Main program work
    select {}
}

Thus, SIGHUP serves as a signal to notify the process to update its configuration or terminate gracefully.