VS代码:如何在launch.json中通过shell命令获取进程ID？

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Program",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/your_program",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "miDebuggerPath": "/path/to/gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "get-pid"
        }
    ],
    "compounds": [],
    "version": "0.2.0",
    "tasks": [
        {
            "label": "get-pid",
            "type": "shell",
            "command": "sh",
            "args": [
                "-c",
                "echo $$ > pid.txt && cat pid.txt"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "presentation": {
                "reveal": "always"
            }
        }
    ]
}