API interaction scripts in Bash Scripting

Introduction

API interaction scripts let you talk to other programs or services automatically. This helps you get or send data without doing it by hand.

You want to get weather updates automatically from a weather service.

You need to send data to a website or app regularly, like uploading a file.

You want to check your email or messages using a script.

You want to automate getting stock prices or news from the internet.

You want to control smart devices by sending commands through their API.

Syntax

Bash Scripting

curl [options] URL

curl is a command-line tool to send requests to APIs.

You can use options like -X to set the request method (GET, POST), and -d to send data.

Examples

Sends a simple GET request to get data from the API.

Bash Scripting

curl https://api.example.com/data

Sends a POST request with JSON data to create a new user.

Bash Scripting

curl -X POST -H "Content-Type: application/json" -d '{"name":"John"}' https://api.example.com/users

Adds a header for authorization to access protected data.

Bash Scripting

curl -H "Authorization: Bearer TOKEN" https://api.example.com/secure-data

Sample Program

This script calls a weather API to get the current temperature for London. It uses curl to send the request and jq to read the temperature from the JSON response.

Bash Scripting

#!/bin/bash

# Simple script to get current weather from a public API
API_URL="https://api.weatherapi.com/v1/current.json"
API_KEY="your_api_key_here"
CITY="London"

response=$(curl -s "${API_URL}?key=${API_KEY}&q=${CITY}")

# Extract temperature using jq (JSON parser)
temp_c=$(echo "$response" | jq '.current.temp_c')

echo "The current temperature in $CITY is ${temp_c}°C."

Important Notes

Make sure you have curl installed on your system.

For JSON responses, jq is very helpful to extract data easily.

Always keep your API keys secret and do not share them publicly.

Summary

API scripts automate talking to web services to get or send data.

curl is the main tool to send requests in bash scripts.

Use headers and data options to customize your API calls.