Portable Graymap

import magic
# Libmagic natively detects PGM files and correctly identifies them based on the P2/P5 signature
print(magic.from_file('scan.pgm', mime=True)) # Outputs 'image/x-portable-graymap'

const fs = require('fs');
// Manually checking the PGM magic bytes (P2 or P5)
const buffer = Buffer.alloc(2);
const fd = fs.openSync('scan.pgm', 'r');
fs.readSync(fd, buffer, 0, 2, 0);
fs.closeSync(fd);
const isPGM = buffer[0] === 0x50 && (buffer[1] === 0x32 || buffer[1] === 0x35);
console.log('Is Portable Graymap (PGM):', isPGM);

import (
    "bytes"
    "net/http"
)
// Native Go HTTP detection does not recognize PGM natively.
// Check directly for the P2 or P5 signatures:
// isPGM := len(buf) >= 2 && buf[0] == 'P' && (buf[1] == '2' || buf[1] == '5')

$mime = mime_content_type('scan.pgm');
echo $mime; // Standard PHP setups typically return 'image/x-portable-graymap'