uuidgen
Generate new UUID values
TLDR
Create a random UUID (v4)
$ uuidgen -r
Create a time-based UUID (v1)$ uuidgen -t
Create a SHA1-based UUID (v5)$ uuidgen -s -n @dns -N [name]
Create a MD5-based UUID (v3)$ uuidgen -m -n @dns -N [name]
SYNOPSIS
uuidgen [options]
DESCRIPTION
uuidgen creates a new universally unique identifier (UUID). By default it generates a random UUID (version 4). Time-based (v1) UUIDs include timestamp and MAC address. Name-based UUIDs (v3/v5) are deterministic, generating the same UUID for the same namespace and name combination.
UUIDs are 128-bit identifiers commonly used for unique identification in databases, distributed systems, and file systems.
PARAMETERS
-r, --random
Generate random UUID (version 4)-t, --time
Generate time-based UUID (version 1)-s, --sha1
Generate SHA1-based UUID (version 5)-m, --md5
Generate MD5-based UUID (version 3)-n, --namespace _ns_
Namespace for name-based UUIDs (@dns, @url, @oid, @x500)-N, --name _name_
Name for name-based UUIDs-x, --hex
Output UUID without hyphens-c
Output in C struct initialization format
UUID VERSIONS
v1: Time and MAC address based
v3: MD5 hash of namespace and name
v4: Random
v5: SHA1 hash of namespace and name
CAVEATS
Time-based UUIDs expose the MAC address of the generating machine. For privacy, prefer random UUIDs. Part of the util-linux package.
SEE ALSO
uuid(1)