How to automate scripts in Replit

Create a new file in your project with a .sh extension, such as scripts/setup.sh. Write your commands in the file using standard bash syntax. Start the file with the shebang line #!/bin/bash to specify the shell interpreter. After saving the file, open the Shell terminal from the Tools dock and make the script executable with chmod +x scripts/setup.sh. You can then run it with ./scripts/setup.sh. Shell scripts are useful for grouping multiple commands that you run together regularly.

1#!/bin/bash
2# scripts/setup.sh - Project setup automation
3
4echo "Starting project setup..."
5
6# Install Node.js dependencies
7npm install
8
9# Run database migrations
10npm run migrate
11
12# Seed the database with test data
13npm run seed
14
15# Build CSS if using Tailwind
16npm run build:css
17
18echo "Setup complete!"

The onBoot key in the .replit file runs a command every time the Replit environment starts. This is useful for setup tasks that need to happen before your app runs, like installing dependencies, running migrations, or setting up the environment. Open the .replit file (enable Show hidden files in the file tree menu if you do not see it) and add the onBoot key at the top level. The command runs once when the workspace boots, not on every Run click. If you need multiple commands, chain them with && or point to a shell script.

1# .replit
2entrypoint = "src/server.js"
3onBoot = "npm install && npm run migrate"
4run = "node src/server.js"
5
6[nix]
7channel = "stable-24_05"
8packages = ["nodejs-20_x"]

The run key in .replit supports running multiple processes simultaneously using the ampersand operator and the wait command. This is useful when your project has both a backend server and a frontend build process that need to run together. Each process runs in the background, and wait keeps the Run button active until all processes complete. You can also use this to run a file watcher alongside your main server.

1# Run backend and frontend dev servers simultaneously
2run = "node server.js & npm run dev:css & wait"
3
4# Or use an array for a single command
5run = ["node", "src/server.js"]

Scheduled Deployments run your app on a defined schedule, making them ideal for tasks like daily database backups, weekly report generation, or periodic API data syncing. Open the Deployments pane from the Tools dock and select Scheduled as the deployment type. Enter a schedule using natural language like 'Every day at 3 AM' or 'Every Monday at 10 AM.' Add the build and run commands that execute your task. The deployment runs, completes the task, and shuts down. Billing is $1/month base plus compute time at $0.000061 per second.

1// scripts/daily-backup.js
2// Run as a Scheduled Deployment daily
3
4import pg from 'pg';
5import fs from 'fs';
6
7const pool = new pg.Pool({
8  connectionString: process.env.DATABASE_URL,
9});
10
11async function backup() {
12  console.log(`Backup started at ${new Date().toISOString()}`);
13  
14  const tables = ['users', 'products', 'orders'];
15  
16  for (const table of tables) {
17    const result = await pool.query(`SELECT * FROM ${table}`);
18    console.log(`${table}: ${result.rows.length} rows exported`);
19    // Process or send data to external storage
20  }
21  
22  console.log('Backup completed successfully');
23  process.exit(0); // Exit so the scheduled job completes
24}
25
26backup().catch((err) => {
27  console.error('Backup failed:', err.message);
28  process.exit(1);
29});

The [deployment] section in .replit has separate build and run commands for production. The build command runs once during deployment and is where you install production dependencies, compile TypeScript, build CSS, and run any preparation steps. The run command starts the production server after the build completes. Organize complex build steps into a dedicated shell script to keep the .replit file clean.

1#!/bin/bash
2# scripts/build.sh - Production build automation
3
4set -e  # Exit on any error
5
6echo "Installing production dependencies..."
7npm ci --production
8
9echo "Building TypeScript..."
10npx tsc
11
12echo "Building CSS..."
13npm run build:css
14
15echo "Running database migrations..."
16npm run migrate
17
18echo "Build complete!"

Your scripts may need to behave differently in development versus production. Use the REPLIT_DEPLOYMENT environment variable to detect the environment. In shell scripts, check with an if statement. In Node.js, read process.env.REPLIT_DEPLOYMENT. This lets you skip database seeding in production, use different API endpoints, or adjust logging verbosity based on the environment.

1#!/bin/bash
2# scripts/init.sh - Environment-aware initialization
3
4if [ "$REPLIT_DEPLOYMENT" = "1" ]; then
5  echo "Production environment detected"
6  npm ci --production
7  npm run migrate
8else
9  echo "Development environment detected"
10  npm install
11  npm run migrate
12  npm run seed
13  echo "Test data seeded"
14fi