Script

When you will meet it

AI install guides often say 'download this setup.sh and run it', and you will often tell an agent to 'write a script to handle these files'. If you do not know a script is just a list of commands, you will not dare open it — and then you cannot judge whether it is safe, even though you are about to be asked to run it.

Minimal example

#!/usr/bin/env bash
set -e                          # 任何一步失敗就停下來，不要硬著往下做

echo "目前所在資料夾：$(pwd)"
python3 --version               # 這一行若失敗，下面就不會執行
node --version 2>/dev/null || echo "沒裝 Node.js（有些工具不需要）"

echo "環境檢查完成"

The #! on line one tells the system which program should read the file — bash here. Save it as check.sh and run it with bash check.sh; to run it as ./check.sh you must first chmod +x check.sh.

What people get wrong

• Treating 'script' and 'program' as two tiers of thing. The difference is mostly scale and intent: a script usually chains existing actions together and finishes, while a program usually runs for a long time and handles varied input. The line is genuinely blurry.
• Piping a downloaded script straight into bash without opening it first. That hands your machine's permissions, unread, to a stranger's file.