#uuid #unique-identifier #output #cli #generator #generate #stdout

app oohid

Generates UUIDs on CLI in various formats, very fast, outputs to .txt or stdout

11 releases

new 0.3.10 May 26, 2024
0.3.9 Apr 11, 2024
0.3.8 Dec 8, 2023

#337 in Command line utilities

Custom license

104 lines



oohid is a fast and efficient command-line interface (CLI) tool for generating Universally Unique Identifiers (UUIDs) in various formats. It allows users to output UUIDs directly to a file or standard output (stdout). Features options for custom formatting, duplicate checking, and verbose output.


  • Generate multiple UUIDs in a single command.
  • Custom formatting options for UUIDs.
  • Output to a file or stdout.
  • Check for and remove duplicate UUIDs.
  • Verbose mode for additional output information.


  • Pretty fast, I'm sure. Uses Rayon for embarassingly parallel tasks, probably some more optimization work to do. SIMD or assembly-level stuff or cache optimization, IDK. ~1 mil/s on my MacBook Pro w. M2 Pro.
  • Formatting options suitable for Python/Rust.
  • For the extra-paranoid (even with 1m UUIDs, the possibility of duplicates is low), duplicate checking.


To install oohid, ensure you have Rust and Cargo installed on your system. Then run the following command:

cargo install oohid


Basic Usage

To generate a single UUID and print it to stdout:


Generating Multiple UUIDs

Generate 5 UUIDs:

oohid --count 5


oohid -c 5

Specifying Format

Specify a custom format for the UUIDs (ul for bare with comma, q for quoted, etc.):

oohid --count 5 --format ul


oohid -c 5 -f ul

Output to a File

Direct the output to a file:

oohid --count 10 --output uuids.txt


oohid -c 10 -o uuids.txt

Checking for Duplicates

Check and remove duplicate UUIDs:

oohid -c 100 --check

Verbose Output

Display benchmarking and checking results:

oohid -c 100000000 -f qlbl -o uuids.txt --check --verbose


Customize the behavior of oohid through command-line flags. Refer to the help command for more details:

oohid --help


Forks and contributions to oohid are welcome.


oohid is distributed under the Unlicense. Do whatever you wish, but attributions would be nice; I am a newb.


Younghyun Chi


~62K SLoC