process

The process module is specifically designed for use in JSH applications.

env

The JSH runtime environment object.

Usage example

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const process = require('process');
console.println(process.env.get('HOME'));

execPath

The absolute file path to the executable file of the current process on the host operating system.

Usage example

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const process = require('process');
console.println(process.execPath);

pid

The process ID of the current process. The value type is number and represents the process ID.

Usage example

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const process = require('process');
console.println(process.pid);

ppid

The process ID of the parent process. The value type is number and represents the parent process ID.

Usage example

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const process = require('process');
console.println(process.ppid);

platform

A string that identifies the operating system platform of the host machine. Common values include windows, linux, and darwin (macOS).

Usage example

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const process = require('process');
console.println(process.platform);

arch

A string that identifies the operating system architecture of the host machine. Common values include amd64, aarch64.

Usage example

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const process = require('process');
console.println(process.arch);

version

A string that identifies the JSH runtime version.

Usage example

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const process = require('process');
console.println(process.version);

versions

An object that provides detailed runtime version information.

• versions.jsh: JSH runtime version string
• versions.go: Go runtime version string

Usage example

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const process = require('process');
console.println('jsh:', process.versions.jsh);
console.println('go :', process.versions.go);

title

A string that identifies the current program.

Usage example

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const process = require('process');
console.println(process.title);

stdin, stdout, stderr

Streams for stdin, stdout, and stderr.

Usage example

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const process = require('process');
process.stdout.write('Enter text: ');
const text = process.stdin.readLine();
console.println('Your input:', text);

// Output:
// Enter text: hello?
// Your input: hello?

addShutdownHook()

Add a callback function that will be called at the termination of the current process.

Syntax

addShutdownHook(()=>{})

Usage example

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const process = require('process');
process.addShutdownHook(()=>{
    console.println("shutdown hook called.");
})
console.println("running...")

// Output:
// running...
// shutdown hook called.

exit()

Exit the current process. If the code is omitted, default is 0.

Syntax

exit([code])

Usage example

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const process = require('process');
process.exit(-1);

which()

Finds a JavaScript command in PATH and returns the resolved file path.

If the command does not include .js, it is added automatically.

Syntax

which(command)

Usage example

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const process = require('process');
console.println(process.which('echo')); // e.g. /sbin/echo.js

expand()

Expands environment variables such as $HOME and ${HOME} in a string.

Syntax

expand(value)

Usage example

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const process = require('process');
console.println(process.expand('$HOME/file.txt'));
console.println(process.expand('${HOME}/../lib/file.txt'));

exec()

Executes a JavaScript command file and returns its exit code.

Syntax

exec(command, ...args)

Usage example

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const process = require('process');
const path = process.which('echo');
const code = process.exec(path, 'hello from exec');
console.println('exit code:', code);

execString()

Executes JavaScript source code from a string and returns its exit code.

Syntax

execString(source, ...args)

Usage example

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const process = require('process');
const code = process.execString("console.println('hello from execString')");
console.println('exit code:', code);

dispatchEvent()

Dispatches an event to an event emitter object on the JSH event loop.

This function returns true if the event is scheduled, false if the event loop is already terminated.

Syntax

dispatchEvent(target, eventName, ...args)

Usage example

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const process = require('process');
process.on('hello', (msg) => console.println(msg));
const ok = process.dispatchEvent(process, 'hello', 'from dispatchEvent');
console.println('scheduled:', ok);

now()

Returns the current time as a JavaScript date-time object.

Usage example

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const process = require('process');
const now = process.now();
console.println(typeof now); // object

chdir()

Changes the current working directory.

If path is empty, JSH resolves it to $HOME.

Syntax

chdir(path)

Usage example

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const process = require('process');
console.println('before:', process.cwd());
process.chdir('/lib');
console.println('after :', process.cwd());

cwd()

Returns the current working directory path.

Usage example

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const process = require('process');
console.println(process.cwd());

nextTick()

Schedules a callback to run on the next event loop turn.

If the first argument is not a function, this call does nothing and returns undefined.

Syntax

nextTick(callback, ...args)

Usage example

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const process = require('process');
console.println('main');
process.nextTick((a, b) => console.println('tick:', a, b), 'first', 'second');

memoryUsage()

Returns memory usage information as an object.

Current implementation returns placeholder numeric values (0) for all fields.

Returned fields

• rss
• heapTotal
• heapUsed
• external
• arrayBuffers

Usage example

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const process = require('process');
const mem = process.memoryUsage();
console.println(typeof mem.rss, typeof mem.heapUsed);

cpuUsage()

Returns CPU usage information.

Current implementation returns placeholder numeric values (0) for both fields.

Returned fields

• user
• system

Usage example

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const process = require('process');
const cpu = process.cpuUsage();
console.println(typeof cpu.user, typeof cpu.system);

uptime()

Returns process uptime in seconds as a number.

Usage example

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const process = require('process');
const up = process.uptime();
console.println('uptime >= 0:', up >= 0);

hrtime()

Returns a high-resolution time tuple as [seconds, nanoseconds].

If a previous tuple is provided, it returns the elapsed time from that point.

Syntax

hrtime([previous])

Usage example

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const process = require('process');
const start = process.hrtime();
const diff = process.hrtime([start[0], start[1]]);
console.println(Array.isArray(diff), diff.length);

kill()

Sends a signal request to the given process id.

Current implementation is a placeholder:

• returns an Error object when pid is missing
• returns true when pid is provided (signal defaults to SIGTERM)

Syntax

kill(pid[, signal])

Usage example

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const process = require('process');
console.println(process.kill(12345, 'SIGKILL'));

dumpStack()

Prints the current JavaScript call stack up to the specified depth for debugging.

Syntax

dumpStack(depth)

Usage example

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const process = require('process');
function trace() {
    process.dumpStack(5);
}
trace();