Bun Shell Bun provides powerful shell scripting capabilities with template literals and spawn APIs. Bun.$ (Shell Template) Basic Usage import { $ } from "bun" ; // Run command await $ echo "Hello World" ; // Get output const result = await $ ls -la . text ( ) ; console . log ( result ) ; // JSON output const pkg = await $ cat package.json . json ( ) ; console . log ( pkg . name ) ; Variable Interpolation import { $ } from "bun" ; const name = "world" ; const dir = "./src" ; // Safe interpolation (escaped) await $ echo "Hello ${ name } " ; await $ ls ${ dir } ; // Array expansion const files = [ "a.txt" , "b.txt" , "c.txt" ] ; await $ touch ${ files } ; Piping import { $ } from "bun" ; // Pipe commands const result = await $ cat file.txt | grep "pattern" | wc -l . text ( ) ; // Chain with JavaScript const files = await $ ls -la . text ( ) ; const lines = files . split ( "\n" ) . filter ( line => line . includes ( ".ts" ) ) ; Error Handling import { $ } from "bun" ; // Throws on non-zero exit try { await $ exit 1 ; } catch ( err ) { console . log ( err . exitCode ) ; // 1 console . log ( err . stderr ) ; } // Quiet mode (no throw) const result = await $ exit 1 . quiet ( ) ; console . log ( result . exitCode ) ; // 1 // Check exit code const { exitCode } = await $ grep pattern file.txt . quiet ( ) ; if ( exitCode !== 0 ) { console . log ( "Pattern not found" ) ; } Output Types import { $ } from "bun" ; // Text const text = await $ echo hello . text ( ) ; // JSON const json = await $ cat data.json . json ( ) ; // Lines const lines = await $ ls . lines ( ) ; // Blob const blob = await $ cat image.png . blob ( ) ; // ArrayBuffer const buffer = await $ cat binary.dat . arrayBuffer ( ) ; Environment Variables import { $ } from "bun" ; // Set env for command await $ echo $MY_VAR . env ( { MY_VAR : "value" } ) ; // Access current env $ . env . MY_VAR = "value" ; await $ echo $MY_VAR ; // Clear env await $ env . env ( { } ) ; Working Directory import { $ } from "bun" ; // Change directory for command await $ pwd . cwd ( "/tmp" ) ; // Or globally $ . cwd ( "/tmp" ) ; await $ pwd ; Bun.spawn Basic Spawn const proc = Bun . spawn ( [ "echo" , "Hello World" ] ) ; const output = await new Response ( proc . stdout ) . text ( ) ; console . log ( output ) ; // "Hello World\n" With Options const proc = Bun . spawn ( [ "node" , "script.js" ] , { cwd : "./project" , env : { NODE_ENV : "production" , ... process . env , } , stdin : "pipe" , stdout : "pipe" , stderr : "pipe" , } ) ; // Write to stdin proc . stdin . write ( "input data\n" ) ; proc . stdin . end ( ) ; // Read stdout const output = await new Response ( proc . stdout ) . text ( ) ; const errors = await new Response ( proc . stderr ) . text ( ) ; // Wait for exit const exitCode = await proc . exited ; Stdio Options // Inherit (use parent's stdio) Bun . spawn ( [ "ls" ] , { stdio : [ "inherit" , "inherit" , "inherit" ] } ) ; // Pipe (capture output) Bun . spawn ( [ "ls" ] , { stdin : "pipe" , stdout : "pipe" , stderr : "pipe" } ) ; // Null (ignore) Bun . spawn ( [ "ls" ] , { stdout : null , stderr : null } ) ; // File (redirect to file) Bun . spawn ( [ "ls" ] , { stdout : Bun . file ( "output.txt" ) , stderr : Bun . file ( "errors.txt" ) , } ) ; Streaming Output const proc = Bun . spawn ( [ "tail" , "-f" , "log.txt" ] , { stdout : "pipe" , } ) ; const reader = proc . stdout . getReader ( ) ; while ( true ) { const { done , value } = await reader . read ( ) ; if ( done ) break ; console . log ( new TextDecoder ( ) . decode ( value ) ) ; } Bun.spawnSync // Synchronous execution const result = Bun . spawnSync ( [ "ls" , "-la" ] ) ; console . log ( result . exitCode ) ; console . log ( result . stdout . toString ( ) ) ; console . log ( result . stderr . toString ( ) ) ; console . log ( result . success ) ; // exitCode === 0 Shell Scripts Shebang Scripts

!/usr/bin/env bun

import { $ } from "bun" ; // Script logic const branch = await $ git branch --show-current . text ( ) ; console . log ( Current branch: ${ branch . trim ( ) } ) ; await $ npm test ; await $ npm run build ; chmod +x script.ts ./script.ts Complex Script

!/usr/bin/env bun

import { $ } from "bun" ; async function deploy ( ) { console . log ( "🚀 Starting deployment..." ) ; // Check for uncommitted changes const status = await $ git status --porcelain . text ( ) ; if ( status . trim ( ) ) { console . error ( "❌ Uncommitted changes found!" ) ; process . exit ( 1 ) ; } // Run tests console . log ( "🧪 Running tests..." ) ; await $ bun test ; // Build console . log ( "🏗️ Building..." ) ; await $ bun run build ; // Deploy console . log ( "📦 Deploying..." ) ; await $ rsync -avz ./dist/ server:/app/ ; console . log ( "✅ Deployment complete!" ) ; } deploy ( ) . catch ( ( err ) => { console . error ( "❌ Deployment failed:" , err ) ; process . exit ( 1 ) ; } ) ; Parallel Commands import { $ } from "bun" ; // Run in parallel await Promise . all ( [ $ npm run lint , $ npm run typecheck , $ npm run test , ] ) ; // Or with spawn const procs = [ Bun . spawn ( [ "npm" , "run" , "lint" ] ) , Bun . spawn ( [ "npm" , "run" , "typecheck" ] ) , Bun . spawn ( [ "npm" , "run" , "test" ] ) , ] ; await Promise . all ( procs . map ( p => p . exited ) ) ; Interactive Commands import { $ } from "bun" ; // Pass through stdin const proc = Bun . spawn ( [ "node" ] , { stdin : "inherit" , stdout : "inherit" , stderr : "inherit" , } ) ; await proc . exited ; Process Management const proc = Bun . spawn ( [ "long-running-process" ] ) ; // Kill process proc . kill ( ) ; // SIGTERM proc . kill ( "SIGKILL" ) ; // Force kill // Check if running console . log ( proc . killed ) ; // Get PID console . log ( proc . pid ) ; // Wait with timeout const timeout = setTimeout ( ( ) => proc . kill ( ) , 5000 ) ; await proc . exited ; clearTimeout ( timeout ) ; Common Patterns Run npm/bun scripts import { $ } from "bun" ; await $ bun run build ; await $ bun test ; await $ bunx tsc --noEmit ; Git Operations import { $ } from "bun" ; const branch = await $ git branch --show-current . text ( ) ; const commit = await $ git rev-parse HEAD . text ( ) ; const status = await $ git status --short . text ( ) ; if ( status ) { await $ git add -A ; await $ git commit -m "Auto commit" ; } File Operations import { $ } from "bun" ; // Find files const files = await $ find . -name "*.ts" . lines ( ) ; // Search content const matches = await $ grep -r "TODO" src/ . text ( ) ; // Archive await $ tar -czf backup.tar.gz ./data ; Common Errors Error Cause Fix Command not found Not in PATH Use absolute path Permission denied Not executable chmod +x Exit code 1 Command failed Check stderr EPIPE Broken pipe Handle process exit When to Load References Load references/advanced-scripting.md when: Complex pipelines Process groups Signal handling Load references/cross-platform.md when: Windows compatibility Path handling Shell differences