# DTLinux Files and Folders

This page is a guide to which folders are used by DTLinux, which files go in those folders, and what those files control. Domain Time II for Linux follows the Linux Filesystem Hierarchy Standard conventions as closely as possible.

## /usr/bin

DTLinux does not put any executable files in /usr/bin. It does, however, create three symlinks so you can access DTLinux programs without having to specify the full path.

/usr/bin/dtlinux |  | symlink to /opt/domtime/bin/dtlinux executable
/usr/bin/dtcheck |  | symlink to /opt/domtime/bin/dtcheck executable
/usr/bin/dtlinux-update |  | symlink to /opt/domtime/update.sh script

## /etc/opt/domtime

Location for main configuration files

dtlinux.conf |  | The main configuration file. It is world-readable, but requires root or sudo to edit
dtlinux.keys |  | Symmetric keys for use with NTP, DT2, and PTP. Requires root or sudo to read or write

## /opt/domtime

Main DTLinux application folder. It contains documentation files, scripts, and other information

SUPPORT.txt |  | Information on how to obtain support
help.html |  | Link to online documentation
LICENSE.txt |  | Symlink to either LICENSE_EVALUATION.txt or LICENSE_REGISTERED.txt
CHANGELOG.txt |  | Historical record of changes in each version
VERSION.txt |  | Current version information
README.txt |  | Generic instructions on how to install or remove DTLinux, plus other vital information
update.sh |  | Bash script to handle updates. Use the symlink dtlinux-update to access this script
remove.sh |  | Bash script to remove dtlinux from your system. Requires root or sudo
help.sh |  | Bash script to launch a browser to online documentation
UpdatingDTLinux.html |  | An HTML reference page explaining how to use dtlinux-update and configure upstream servers
FilesAndFolders.html |  | The page you are reading now
authorized.managers |  | Optional textual control file, created using sudo dtcheck -authorize <NameOrIP> This file contains IPAddress=hash pairs, along with instructions.
manager.password |  | Optional binary control file, created or deleted using sudo dtcheck -setPassword This file is encrypted. If present, the password is required for remote control

## /opt/domtime/etc

License files, original dtlinux.conf, optional license file

dtlinux.conf.sample |  | Original dtlinux.conf file, updated every time you upgrade DTLinux
dtlinux.keys.sample |  | Example symmetric keys file
LICENSE_EVALUATION.txt |  | The license that applies to an unregistered evaluation copy of DTLinux
LICENSE_REGISTERED.txt |  | The license that applies when you register your copy of DTLinux and apply your license key
dtlinux.license |  | A binary file containing registration information. This file will only exist after you apply your license key

## /opt/domtime/bin

Executables and hashes

hashes.txt |  | A text file containing the SHA256 hashes for dtlinux and dtcheck
dtlinux |  | The main DTLinux executable file. Use sudo dtlinux -help to see options
dtcheck |  | A utility program. Use dtcheck -help to see options

## /opt/domtime/packages

Optional folder. If present, it contains the .DEB, .RPM, or .TGZ file corresponding to the package installed by Domain Time II Manager when pushing an upgrade.

## /opt/domtime/archives

Optional folder. It is created when you use Manager to push configuration or other files. If present, it contains the versions of files that were replaced, and a log showing archival activity.

updatelog.txt |  | Update activity log file

## /var/opt/domtime

Persistent state storage for the dtlinux service

dtlinux.dat |  | State information for the dtlinux service. You should never edit this file

## /var/opt/domtime/backup

Default folder for dtcheck -backup if you do not provide your own folder name. Files in this folder require root or sudo to read. You should never edit files created by dtcheck -backup.

## /run/domtime

Runtime information for the dtlinux service

dtlinux.pid |  | Present and locked when the dtlinux service is running

## /var/log/domtime

The default location for dtlinux logs. You may change the log location by editing the dtlinux.conf file.

dtlinux.log |  | The main service log file
dtlinux.startup.log |  | A file created each time the dtlinux service is restarted
drift.dt |  | Binary drift file. Read it using dtcheck -txt drift.dt or dtcheck -csv drift.dt
driftptp.dt |  | Binary PTP drift file. Read it using dtcheck -txt driftptp.dt or dtcheck -csv driftptp.dt

## /run/domtime

Temp folder used by the dtlinux service. It is normally empty except for brief periods when the dtlinux service is receiving files or preparing files to send to Domain Time II Manager. The service formerly used /tmp/domtime for this purpose.

## /lib/systemd/system or /usr/lib/systemd/system

Depending on your distro type, systemd unit files belong in either /lib/systemd/system or in /usr/lib/systemd/system. In many cases, /usr/lib is a link to /lib. One or both of the links below should allow you to view the dtlinux.service file.

/lib/systemd/system/dtlinux.service /usr/lib/systemd/system/dtlinux.service |  | systemd service unit file

This document last updated on 18 Jun 2026