---
id: php-file-create
title: "PHP File Create"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["fwrite()", "append mode", "PHP 파일 생성/쓰기"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.9
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["php", "programming", "w3schools", "files", "fwrite"]
raw_sources: ["https://www.w3schools.com/php/php_file_create.asp"]
applied_in: []
github_commit: ""
---

# [[PHP File Create]]

## 🎯 한 줄 통찰 (One-line insight)
PHP uses the SAME function (`fopen()`) to both open AND create files — passing `"w"` or `"a"` mode on a non-existent filename silently creates it, meaning there's no separate "create file" function; opening a file for writing IS how you create one. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`fopen($name, "w")` on a nonexistent file** — creates it. [S1]
- **`fwrite($file, $string)`** — writes a string to an open file. [S1]
- **`"w"` mode overwrites** — opening an EXISTING file in `"w"` mode ERASES all its content before writing new data. [S1]
- **`"a"` mode appends** — preserves existing content, adds new data at the end. [S1]
- **File permissions** — PHP must have write access to the target directory, or `fopen`/`fwrite` will fail. [S1]

## 📖 세부 내용 (Details)
- Create a new file: `$myfile = fopen("testfile.txt", "w")`. [S1]
- Write multiple lines: `$myfile = fopen("newfile.txt", "w") or die("Unable to open file!"); fwrite($myfile, "John Doe\n"); fwrite($myfile, "Jane Doe\n"); fclose($myfile);`. [S1]
- Overwrite demonstration: opening the same "newfile.txt" again with `"w"` and writing different names ERASES "John Doe"/"Jane Doe" entirely, leaving only the new content. [S1]
- Append demonstration: opening with `"a"` and writing adds new lines AFTER the existing content, without erasing anything. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **w 모드의 파괴적 동작**: 기존 파일을 "w" 모드로 열면 기존 데이터가 전부 삭제된다는 점이 이전/이후 내용 비교 예제로 직접 증명됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 로그 파일에 새 항목을 추가할 때 "a" 모드를 사용하는 것이 append 모드의 대표 실전 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Append mode preserves existing content (PHP):
```php
$myfile = fopen("newfile.txt", "a") or die("Unable to open file!");
fwrite($myfile, "Donald Duck\n");
fwrite($myfile, "Goofy Goof\n");
fclose($myfile);
// existing content is preserved; new lines added at the end
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.90
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[PHP Tutorial]]
- **관련 개념:** [[PHP File Open]], [[PHP File Upload]]
- **참조 맥락:** 파일 쓰기/덮어쓰기/추가 — 파일 업로드(File Upload) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP File Create/Write — https://www.w3schools.com/php/php_file_create.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "PHP File Create/Write" page (Astra wiki-curation, P-Reinforce v3.1 format).
