What Linux signals do you know? What are they used for?

In Linux, signals are a mechanism for asynchronous notification of processes about events. They are used for process control, error handling, and interaction with the OS.

Main signals:

• SIGINT (2) — process interruption (usually Ctrl+C in the terminal).
• SIGTERM (15) — request for graceful process termination.
• SIGKILL (9) — immediate process termination (cannot be caught).
• SIGSTOP (19) — process suspension (cannot be ignored).
• SIGCONT (18) — continuation of a suspended process.
• SIGSEGV (11) — segmentation fault (invalid memory access).
• SIGALRM (14) — timer signal.
• SIGCHLD (17) — notification to the parent process about child process termination.

Usage:

• Managing process lifecycle (start, stop, restart).
• Handling exceptional situations (e.g., resource cleanup on termination).
• Implementing timeouts and periodic tasks.

Example of handling SIGINT signal in Go:

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

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

    fmt.Println("Waiting for SIGINT (Ctrl+C)...")
    <-sigs
    fmt.Println("SIGINT received, terminating")
}