PATH and file paths
Also: 路徑 · 環境變數 PATH · command not found
A path is a file's address. PATH is the list of folders the computer searches when you name a program.
When you will meet it
"command not found" is the most common beginner error, and nine times in ten the tool IS installed — PATH just does not include its folder. Understanding this saves an afternoon of reinstalling.
An analogy
If you just say "send a burger", someone needs a list of places to look. PATH is that list, and order matters: the first match wins.
Minimal example
echo $PATH # 看目前的搜尋清單（Windows PowerShell：$env:Path -split ';'）
which claude # 這個程式實際在哪裡（Windows：where.exe claude）If `which` prints a path, the tool exists and PATH is the problem. If it prints nothing, the tool really is missing.
What people get wrong
- Reinstalling on sight of "command not found". Check with which/where first.
- Forgetting quotes around a path with spaces. `cd My Projects` reads as two arguments; write `cd "My Projects"`.
Related terms
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