PHP file handling allows us to create, open, read, write, append, and close files. It is useful for storing text, logs, and other information on a server.
PHP provides functions such as fopen(),
fread(), fwrite(),
fgets(), and fclose() to work
with files.
fopen() opens a file.fread() reads file contents.fwrite() writes data to a file.fclose() closes an open file.file_exists() checks whether a file exists.Create a file named sample.txt in the same
directory as your PHP file.
Example:
<?php
$file = "sample.txt";
if (file_exists($file)) {
echo "File exists.";
} else {
echo "File does not exist.";
}
?>PHP file operations depend on file permissions and the directory in which the script runs.
The fopen() function opens a file using a
specified mode.
<?php
$file = fopen("sample.txt", "r");
if ($file !== false) {
echo "File opened successfully.";
fclose($file);
} else {
echo "Unable to open the file.";
}
?>Output: File opened successfully.
| Mode | Meaning |
|---|---|
r |
Read only; file must exist. |
r+ |
Read and write; file must exist. |
w |
Write only; creates a file or truncates an existing file. |
w+ |
Read and write; creates or truncates a file. |
a |
Write at the end; creates the file if needed. |
a+ |
Read and append; creates the file if needed. |
x |
Create a new file for writing; fails if it exists. |
Always check whether fopen() succeeded before
using the returned file handle.
The fwrite() function writes data to an open
file. The w mode creates a new file if
necessary and removes the previous contents of an existing file.
<?php
$file = fopen("student.txt", "w");
if ($file !== false) {
fwrite($file, "Student Name: Rahul\n");
fwrite($file, "Course: PHP Programming\n");
fclose($file);
echo "Data written successfully.";
} else {
echo "Unable to open the file.";
}
?>Output: Data written successfully.
Contents of student.txt:
Student Name: Rahul
Course: PHP Programming
The \n character adds a newline in the file.
On systems where exact newline formatting matters, use
the appropriate newline sequence.
The fread() function reads a specified number
of bytes from an open file.
<?php
$file = fopen("student.txt", "r");
if ($file !== false) {
$content = fread($file, filesize("student.txt"));
fclose($file);
echo nl2br(
htmlspecialchars($content, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8')
);
} else {
echo "Unable to open the file.";
}
?>
This example assumes student.txt exists and
is not empty. For an empty file, filesize()
returns zero, so no bytes are read.
Displayed output:
Student Name: Rahul
Course: PHP Programming
fread() reads bytes, so take care when
handling large files or multibyte text.
The fgets() function reads one line at a time.
It is useful when a file contains multiple lines.
<?php
$file = fopen("student.txt", "r");
if ($file !== false) {
while (($line = fgets($file)) !== false) {
echo htmlspecialchars(
$line,
ENT_QUOTES | ENT_SUBSTITUTE,
'UTF-8'
) . "<br>";
}
fclose($file);
} else {
echo "Unable to open the file.";
}
?>Output:
Student Name: Rahul
Course: PHP Programming
The loop stops when fgets() returns
false, such as at the end of the file.
The a mode writes new data at the end of a
file without removing its existing contents.
<?php
$file = fopen("student.txt", "a");
if ($file !== false) {
fwrite($file, "\nStudent Name: Priya");
fwrite($file, "\nCourse: Web Development");
fclose($file);
echo "New data appended successfully.";
} else {
echo "Unable to open the file.";
}
?>Output: New data appended successfully.
Updated file contents:
Student Name: Rahul
Course: PHP Programming
Student Name: Priya
Course: Web DevelopmentRun this example multiple times and the same information will be appended repeatedly. Add checks if duplicate entries must be prevented.
PHP provides several convenient file handling functions.
file_exists() checks whether a path exists.filesize() returns a file's size in bytes.file_get_contents() reads a file into a string.file_put_contents() writes a string to a file.unlink() deletes a file.is_file() checks whether a path refers to a regular file.<?php
$file = "student.txt";
if (is_file($file) && is_readable($file)) {
$content = file_get_contents($file);
if ($content !== false) {
echo nl2br(
htmlspecialchars(
$content,
ENT_QUOTES | ENT_SUBSTITUTE,
'UTF-8'
)
);
} else {
echo "Unable to read the file.";
}
} else {
echo "File is missing or not readable.";
}
?><?php
$result = file_put_contents(
"message.txt",
"Welcome to PHP file handling."
);
if ($result !== false) {
echo "File saved successfully.";
} else {
echo "Unable to save the file.";
}
?>
By default, file_put_contents() replaces
existing file contents. Use FILE_APPEND
to append instead.
The unlink() function deletes a file.
Use it carefully because deletion may be difficult to reverse.
<?php
$file = "old.txt";
if (is_file($file)) {
if (unlink($file)) {
echo "File deleted successfully.";
} else {
echo "Unable to delete the file.";
}
} else {
echo "File does not exist.";
}
?>Never allow a user to supply an unrestricted file path for deletion. Restrict operations to an approved directory and validate the requested filename.
<?php
$file = fopen("missing.txt", "r");
if ($file === false) {
echo "Could not open the file.";
} else {
echo "File opened successfully.";
fclose($file);
}
?>Output: Could not open the file.
In production applications, log technical details securely rather than exposing server paths or sensitive error information to visitors.
This example accepts a student name and course through a form and appends the details to a text file.
<?php
$message = "";
if ($_SERVER["REQUEST_METHOD"] === "POST") {
$name = trim($_POST["name"] ?? "");
$course = trim($_POST["course"] ?? "");
if ($name === "" || $course === "") {
$message = "Please enter both name and course.";
} else {
$record = "Name: " . $name
. " | Course: " . $course
. PHP_EOL;
$result = file_put_contents(
__DIR__ . "/students.txt",
$record,
FILE_APPEND | LOCK_EX
);
if ($result !== false) {
$message = "Student details saved successfully.";
} else {
$message = "Unable to save student details.";
}
}
}
?>
<form method="post">
<label for="name">Student Name:</label>
<input type="text" id="name" name="name" required>
<br><br>
<label for="course">Course Name:</label>
<input type="text" id="course" name="course" required>
<br><br>
<button type="submit">Save Student</button>
</form>
<?php if ($message !== ""): ?>
<p>
<?= htmlspecialchars(
$message,
ENT_QUOTES | ENT_SUBSTITUTE,
"UTF-8"
) ?>
</p>
<?php endif; ?>Example file contents:
Name: Rahul | Course: PHP
Name: Priya | Course: Web DevelopmentImportant: This is a basic learning example. In a real application, validate input lengths, use an appropriate storage format, and keep writable files in a directory that is not publicly accessible. File locking helps coordinate concurrent writes but does not replace access controls.
1. Which function opens a file in PHP?
2. Which file mode appends data to the end of a file?
3. Which function deletes a file?