---
id: php-file-open
title: "PHP File Open"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["fopen()", "fread()", "feof()", "PHP 파일 열기/읽기"]
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", "fopen"]
raw_sources: ["https://www.w3schools.com/php/php_file_open.asp"]
applied_in: []
github_commit: ""
---

# [[PHP File Open]]

## 🎯 한 줄 통찰 (One-line insight)
`feof()` is specifically designed for looping through data of UNKNOWN length — rather than counting lines in advance, `while(!feof($myfile)) { echo fgets($myfile); }` keeps reading exactly until the end-of-file marker is hit, making it the correct pattern for files whose size isn't known ahead of time. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`fopen(filename, mode)`** — opens a file; modes: `r` (read), `r+` (read/write, preserves data), `w` (write, erases existing), `w+` (read/write, erases), `a` (append), `a+` (append read/write), `x` (create-only, fails if exists), `x+` (create-only read/write). [S1]
- **`fread($file, length)`** — reads up to `length` bytes; `filesize()` reads the whole file. [S1]
- **`fclose($file)`** — closes an open file; good practice to always close after use to free server resources. [S1]
- **`fgets($file)`** — reads one line; advances the file pointer to the next line after each call. [S1]
- **`feof($file)`** — checks for end-of-file; useful for looping over data of unknown length. [S1]
- **`fgetc($file)`** — reads one character; advances the pointer to the next character. [S1]

## 📖 세부 내용 (Details)
- Open + read whole file: `$myfile = fopen("webdictionary.txt", "r") or die("Error: Unable to open file!"); echo fread($myfile, filesize("webdictionary.txt")); fclose($myfile);`. [S1]
- Read one line: `$myfile = fopen("webdictionary.txt", "r") or die(...); echo fgets($myfile); fclose($myfile);`. [S1]
- Loop until EOF (line by line): `while(!feof($myfile)) { echo fgets($myfile) . "<br>"; }`. [S1]
- Loop until EOF (char by char): `while(!feof($myfile)) { echo fgetc($myfile); }`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — feof()로 파일 끝까지 한 줄씩 읽어 출력하는 것이 알 수 없는 길이의 파일 처리 표준 패턴이다. [S1]

## 💻 코드 패턴 (Code patterns)
Reading a file line by line until EOF (PHP):
```php
$myfile = fopen("webdictionary.txt", "r") or die("Unable to open file!");
while (!feof($myfile)) {
    echo fgets($myfile) . "<br>";
}
fclose($myfile);
```

## ✅ 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]], [[PHP File Create]]
- **참조 맥락:** 파일 열기/읽기/닫기 — 파일 생성/쓰기(File Create) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP File Open/Read/Close — https://www.w3schools.com/php/php_file_open.asp

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