Portable Bitmap

import magic
# Libmagic natively detects PBM files
print(magic.from_file('scanned_doc.pbm', mime=True)) # Outputs 'image/x-portable-bitmap'

const fs = require('fs');
// Manually checking the PBM magic bytes (P1 or P4)
const buffer = Buffer.alloc(2);
const fd = fs.openSync('scanned_doc.pbm', 'r');
fs.readSync(fd, buffer, 0, 2, 0);
fs.closeSync(fd);
const isPBM = buffer[0] === 0x50 && (buffer[1] === 0x31 || buffer[1] === 0x34);
console.log('Is Portable Bitmap (PBM):', isPBM);

import (
    "bytes"
    "net/http"
)
// Native Go HTTP detection does not recognize PBM natively.
// Check directly for the P1 or P4 signatures:
// isPBM := len(buf) >= 2 && buf[0] == 'P' && (buf[1] == '1' || buf[1] == '4')

$mime = mime_content_type('scanned_doc.pbm');
echo $mime; // Standard PHP setups typically return 'image/x-portable-bitmap'