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+# Utilities
+
+## File functions
+
+```ts
+import {
+    readFile,
+    readFileAsync,
+    writeFile,
+    writeFileAsync,
+    monitorFile,
+} from "astal"
+```
+
+### Reading files
+
+```ts
+function readFile(path: string): string
+function readFileAsync(path: string): Promise<string>
+```
+
+### Writing files
+
+```ts
+function writeFile(path: string, content: string): void
+function writeFileAsync(path: string, content: string): Promise<void>
+```
+
+### Monitoring files
+
+```ts
+function monitorFile(
+    path: string,
+    callback: (file: string, event: Gio.FileMonitorEvent) => void,
+): Gio.FileMonitor
+```
+
+## Timeouts and Intervals
+
+```ts
+import { interval, timeout, idle } from "astal"
+```
+
+You can use javascript native `setTimeout` or `setInterval`
+they return a [GLib.Source](https://docs.gtk.org/glib/struct.Source.html) instance.
+Alternatively you can use these functions provided by Astal,
+which return an [Astal.Time](https://aylur.github.io/libastal/class.Time.html) instance.
+
+`Astal.Time` has a `now` signal and a `cancelled` signal.
+
+### Interval
+
+Will immediately execute the function and every `interval` millisecond.
+
+```ts
+function interval(interval: number, callback?: () => void): Astal.Time
+```
+
+### Timeout
+
+Will execute the `callback` after `timeout` millisecond.
+
+```ts
+function timeout(timeout: number, callback?: () => void): Astal.Time
+```
+
+### Idle
+
+Executes `callback` whenever there are no higher priority events pending.
+
+```ts
+function idle(callback?: () => void): Astal.Time
+```
+
+Example:
+
+```ts
+const timer = interval(1000, () => {
+    console.log("optional callback")
+})
+
+timer.connect("now", () => {
+    console.log("tick")
+})
+
+timer.connect("cancelled", () => {
+    console.log("cancelled")
+})
+
+timer.cancel()
+```
+
+## Process functions
+
+```ts
+import { subprocess, exec, execAsync } from "astal"
+```
+
+### Subprocess
+
+You can start a subprocess and run callback functions whenever it outputs to
+stdout or stderr. [Astal.Process](https://aylur.github.io/libastal/class.Process.html) has a `stdout` and `stderr` signal.
+
+```ts
+function subprocess(args: {
+    cmd: string | string[]
+    out?: (stdout: string) => void
+    err?: (stderr: string) => void
+}): Astal.Process
+
+function subprocess(
+    cmd: string | string[],
+    onOut?: (stdout: string) => void,
+    onErr?: (stderr: string) => void,
+): Astal.Process
+```
+
+Example:
+
+```ts
+const proc = subprocess(
+    "some-command",
+    (out) => console.log(out), // optional
+    (err) => console.error(out), // optional
+)
+
+// or with signals
+const proc = subprocess("some-command")
+proc.connect("stdout", (out) => console.log(out))
+proc.connect("stderr", (err) => console.error(err))
+```
+
+### Executing external commands and scripts
+
+```ts
+function exec(cmd: string | string[]): string
+function execAsync(cmd: string | string[]): Promise<string>
+```
+
+Example:
+
+```ts
+try {
+    const out = exec("/path/to/script")
+    console.log(out)
+} catch (err) {
+    console.error(err)
+}
+
+execAsync(["bash", "-c", "/path/to/script.sh"])
+    .then((out) => console.log(out))
+    .catch((err) => console.error(err))
+```
+
+:::warning
+`subprocess`, `exec`, and `execAsync` executes the passed executable as is.
+They are **not** executed in a shell environment,
+they do **not** expand ENV variables like `$HOME`,
+and they do **not** handle logical operators like `&&` and `||`.
+
+If you want bash, run them with bash.
+
+```ts
+exec(["bash", "-c", "command $VAR && command"])
+exec("bash -c 'command $VAR' && command")
+```
+
+:::