Quick start

This section contains a quick guide to common operations in dcc. For a more complete description of features available in dcc, see Usage.


Most DCC records and files require authentication to access, such as that provided by a ligo.org account. By default, dcc assumes you can authenticate yourself and therefore builds and requests URLs for records and files within the restricted part of the DCC, prompting for credentials or using an existing Kerberos ticket. You can specify the --public flag to restrict dcc to accessing public records.

Setting a location to store downloaded records and files

dcc works best if you give it a place to store data downloaded from the DCC, making subsequent access to the same data faster. This can be achieved using the -s or --archive-dir option, or by setting the environment variable DCC_ARCHIVE. The value should be a directory on your file system. For example:

# Use a directory called "dcc" in your home directory.
$ dcc archive -s ~/dcc --files T010075

If the archive directory is not given, dcc uses a temporary directory each time it is invoked, and the data is lost upon program exit.

Viewing a record

Metadata for a record can be viewed on the console by specifying dcc view followed by the DCC number, e.g.:

$ dcc view T010075 --public
number: T010075-v3
url: https://dcc.ligo.org/T010075-v3/public
title: Advanced LIGO Systems Design
modified: 2015-02-17 17:55:30-08:00
authors: Peter Fritschel, Dennis Coyne
This document describes the system design and requirements for the Advanced
LIGO detectors. Only systems-level scope is addressed. For a top-level overall
systems description, see P1400177. For Systems acceptance documentation see
This version has been prepared for the Advanced LIGO Systems Acceptance Review
(Feb 2015). For changes from -v2 to -v3, see the change record file.
1. T010075-v3 aLIGO System Description.pdf
2. Change Record for T010075-v3.docx
3. Change Record for T010075-v3.pdf
4. Zip file of source documents (T010075-v3 System Description.zip)
referenced by: T050036, G1200071, E1200479, E1300945, E1300948, L1000311, L1500043, E1800314
related to:

…which corresponds to what’s on the DCC page itself. Note that the --public flag specifies to retrieve the record from the public DCC page.


Depending on the level of privilege of your credentials, you may see more or less information than that shown above.

Downloading and opening a file

The command dcc open-file accepts a DCC number followed by a number corresponding to the file’s position in the record as shown in the file list output from dcc view, e.g.:

$ dcc open-file T010075 1

dcc will pass the downloaded file to the operating system to be opened using the default application. To instead open a file browser with the downloaded file located, pass the --locate flag.