CMUS (.cmus)
.cmus file signature | application/octet-stream
CMUS is a legacy multimedia file format associated with Carnegie Mellon University and its historical software tools. It was used for storing structured audio, animation, or scene data in research and educational environments. The format is generally safe to inspect, but support is limited and modern applications may not open it correctly; files from untrusted sources should be handled with the same caution as other obsolete media formats.
Magic Bytes
Offset 0
46 4F 52 4D
Sources: Wikipedia
All Known Signatures
2 signature variants are documented for .cmus files across multiple sources.
Extension
.cmus
MIME Type
application/octet-stream
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .cmus files in Python
def is_cmus(file_path: str) -> bool:
"""Check if file is a valid CMUS by magic bytes."""
signature = bytes([0x46, 0x4F, 0x52, 0x4D])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .cmus files in Node.js
function isCMUS(buffer: Buffer): boolean {
const signature = Buffer.from([0x46, 0x4F, 0x52, 0x4D]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .cmus files in Go
func IsCMUS(data []byte) bool {
signature := []byte{0x46, 0x4F, 0x52, 0x4D}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/cmus
curl https://filesignature.org/api/v1/cmus
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .cmus file?
A .cmus file is identified by the magic bytes 46 4F 52 4D at byte offset 0. CMUS is a legacy multimedia file format associated with Carnegie Mellon University and its historical software tools. It was used for storing structured audio, animation, or scene data in research and educational environments. The format is generally safe to inspect, but support is limited and modern applications may not open it correctly; files from untrusted sources should be handled with the same caution as other obsolete media formats.
What are the magic bytes for .cmus files?
The magic bytes for CMUS files are 46 4F 52 4D at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .cmus file?
To validate a .cmus file, read the first bytes of the file and compare them against the known magic bytes (46 4F 52 4D) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .cmus files?
There is no officially registered MIME type for .cmus files. Systems typically use application/octet-stream as a generic fallback when handling this format.
Is it safe to open .cmus files?
CMUS (.cmus) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.