There are multiple ways to trigger one process from another process in Linux. Here are a few common methods:
- Signals: One process can send a signal to the other process to trigger a specific action. Common signals include SIGTERM, SIGINT, and SIGKILL. The kill command can be used to send signals to processes using their Process ID (PID). For example, to send a SIGTERM signal, use the command: kill -TERM
- Pipes: Processes can communicate with each other through pipes. A pipe enables the output of one process to be directly used as the input of another process. This can be used to trigger a process by feeding it specific input from another process. Pipes are created using the | (pipe) symbol in the command line. For example:
- System calls: Processes can communicate indirectly through system calls like fork() and exec(). The fork() system call can create a new process, and the child process can be used to trigger an action in another process using the exec() system call. This allows the child process to replace itself with a different process.
- IPC (Inter-Process Communication) mechanisms: Linux provides several IPC mechanisms such as shared memory, message queues, and sockets. These mechanisms allow processes to communicate and trigger each other through shared memory or messaging.
- File-based communication: Processes can communicate through files. One process can write specific data into a file, and the other process can monitor the file for changes and trigger a corresponding action.
The method to use depends on the specific requirements and nature of the processes involved.