Create at least one system user and a group for running this software. You might call them "ups" and "nut". The exact names aren’t important as long as you are consistent.

The process for doing this varies from one system to the next, and explaining how to add users is beyond the scope of this document.

For the purposes of this document, the user name and group name will be ups and nut respectively.

Be sure the new user is a member of the new group! If you forget to do this, you will have problems later on when you try to start upsd.

Configure the source tree for your system. Add the --with-user and --with-group switch to set the user name and group that you created above.

./configure --with-user=ups --with-group=nut

If you need any other switches for configure, add them here. For example:

See Configure options from the User Manual, docs/configure.txt or ./configure --help for all the available options.

If you alter paths with additional switches, be sure to use those new paths while reading the rest of the steps.

Reference: Configure options from the User Manual.

make

This will build the NUT client and server programs and the selected drivers. It will also build any other features that were selected during configuration step above.

su

Install the files to a system level directory:

make install

This will install the compiled programs and man pages, as well as some data files required by NUT. Any optional features selected during configuration will also be installed.

This will also install sample versions of the NUT configuration files. Sample files are installed with names like ups.conf.sample so they will not overwrite any existing real config files you may have created.

If you are packaging this software, then you will probably want to use the DESTDIR variable to redirect the build into another place, i.e.:

make DESTDIR=/tmp/package install
make DESTDIR=/tmp/package install-conf

Create the state path directory for the driver(s) and server to use for storing UPS status data and other auxiliary files, and make it group-writable by the group of the system user you created.

mkdir -p /var/state/ups
chmod 0770 /var/state/ups
chown root:nut /var/state/ups

Set ownership data and permissions on your serial or USB ports that go to your UPS hardware. Be sure to limit access to just the user you created earlier.

These examples assume the second serial port (ttyS1) on a typical Slackware system. On FreeBSD, that would be cuaa1. Serial ports vary greatly, so yours may be called something else.

chmod 0660 /dev/ttyS1
chown root:nut /dev/ttyS1

The setup for USB ports is slightly more complicated. Device files for USB devices, such as /proc/bus/usb/002/001, are usually created "on the fly" when a device is plugged in, and disappear when the device is disconnected. Moreover, the names of these device files can change randomly. To set up the correct permissions for the USB device, you may need to set up (operating system dependent) hotplugging scripts. Sample scripts and information are provided in the scripts/hotplug and scripts/udev directories. For most users, the hotplugging scripts will be installed automatically by "make install".

(If you want to try if a driver works without setting up hotplugging, you can add the "-u root" option to upsd, upsmon, and drivers; this should allow you to follow the below instructions. However, don’t forget to set up the correct permissions later!).

You are now ready to configure NUT, and start testing and using it.

You can jump directly to the NUT configuration.

The Prerequisites for building NUT on different OSes document details tools and dependencies that were added on NUT CI build environments, which now cover many operating systems. This should provide a decent starting point for the build on yours (PRs to update the document are welcome!)

Note that unlike distribution tarballs, Git sources do not include a configure script and some other files — these should be generated by running autogen.sh (or ci_build.sh that calls it).

To build the current tip of development iterations (usually after PR merges that passed CI, reviews and/or other tests), just clone the NUT repository and "master" branch should get checked out by default (also can request that explicitly, per example posted below).

If you want to quickly test a particular pull request, see the link on top of the PR page that says ... wants to merge ... from : ... and copy the proposed-source URL of that "from" part.

For example, in some PR this says jimklimov:issue-1234 and links to https://github.com/jimklimov/nut/tree/issue-1234. For manual git-cloning, just paste that URL into the shell and replace the /tree/ with "-b" CLI option for branch selection, like this:

:; cd /tmp
### Checkout https://github.com/jimklimov/nut/tree/issue-1234
:; git clone https://github.com/jimklimov/nut -b issue-1234

This goes similar to usual build and install from Git:

:; cd /tmp
:; git clone https://github.com/networkupstools/nut
:; cd nut
:; ./autogen.sh
:; ./configure --enable-inplace-runtime # --maybe-some-other-options
:; make -j 4 all && make -j 4 check && sudo make install

Note that make install does not currently handle all the nuances that packaging installation scripts would, such as customizing filesystem object ownership, daemon restarts, etc. or even creating locations like /var/state/ups and /var/run/nut as part of the make target (but e.g. the delivered systemd-tmpfiles configuration can handle that for a large part of the audience). This aspect is tracked as issue #1298

At this point you should revise the locations for PID files (e.g. /var/run/nut) and pipe files (e.g. /var/state/ups) that they exist and permissions remain suitable for NUT run-time user selected by your configuration, and typically stop your original NUT drivers, data-server (upsd) and upsmon, and restart them using the new binaries.

For modern Linux distributions with systemd this replacement procedure could be enhanced like below, to also re-enable services (creating proper symlinks) and to get them started:

:; cd /tmp
:; git clone https://github.com/networkupstools/nut
:; cd nut
:; ./autogen.sh
:; ./configure --enable-inplace-runtime # --maybe-some-other-options
:; make -j 4 all && make -j 4 check && \
    { sudo systemctl stop nut-monitor nut-server || true ; } && \
    { sudo systemctl stop nut-driver.service || true ; } && \
    { sudo systemctl stop nut-driver.target || true ; } && \
    { sudo systemctl stop nut.target || true ; } && \
    sudo make install && \
    sudo systemctl daemon-reload && \
    sudo systemd-tmpfiles --create && \
    sudo systemctl disable nut.target nut-driver.target \
        nut-monitor nut-server nut-driver-enumerator.path \
        nut-driver-enumerator.service && \
    sudo systemctl enable nut.target nut-driver.target \
        nut-monitor nut-server nut-driver-enumerator.path \
        nut-driver-enumerator.service && \
    { sudo systemctl restart udev || true ; } && \
    sudo systemctl restart nut-driver-enumerator.service \
        nut-monitor nut-server

Note the several attempts to stop old service units — naming did change from 2.7.4 and older releases, through 2.8.0, and up to current codebase. Most of the NUT units are now WantedBy=nut.target (which is in turn WantedBy=multi-user.target and so bound to system startup). You should only systemctl enable those units you need on this system — this allows it to not start the daemons you do not need (e.g. not run upsd NUT data server on systems which are only upsmon secondary clients).

The nut-driver-enumerator units (and corresponding shell script) are part of a new feature introduced in NUT 2.8.0, which automatically discovers ups.conf sections and changes to their contents, and manages instances of a nut-driver@.service definition.

You may also have to restart (or reload if supported) some system services if your updates impact them, like udev for updates USB support (note also PR #1342 regarding the change from udev.rules to udev.hwdb file with NUT v2.8.0 or later — you may have to remove the older file manually).

If you are regularly building NUT from GitHub "master" branch, or iterating local development branches of your own, you may get away with shorter constructs to just restart the services after installing newly built files (if you know there were no changes to unit file definitions and dependencies), e.g.:

:; cd /tmp
:; git clone https://github.com/networkupstools/nut
:; cd nut
:; git checkout -b issue-1234 ### your PR branch name, arbitrary
:; ./autogen.sh
:; ./configure --enable-inplace-runtime # --maybe-some-other-options
### Iterate your code changes (e.g. PR draft), build and install with:
:; make -j 4 all && make -j 4 check && \
    sudo make install && \
    sudo systemctl daemon-reload && \
    sudo systemd-tmpfiles --create && \
    sudo systemctl restart \
        nut-driver-enumerator.service nut-monitor nut-server

To install NUT as a package execute:

# pkg install nut

The port is located under sysutils/nut. Use make config to select configuration options, e.g. to build the optional CGI scripts. To install it, use:

# make install clean

For USB UPS devices the NUT package/port installs devd rules in /usr/local/etc/devd/nut-usb.conf to set USB device permissions. devd needs to be restarted for these rules to apply:

# service devd restart

(Re-)connect the device after restarting devd and check that the USB device has the proper permissions. Check the last entries of the system message buffer. You should find an entry like:

# dmesg | tail
[...]
ugen0.2: <INNO TECH USB to Serial> at usbus0

The device file must be owned by group uucp and must be group read-/writable. In the example from above this would be

# ls -Ll /dev/ugen0.2
crw-rw----  1 root  uucp  0xa5 Mar 12 10:33 /dev/ugen0.2

If the permissions are not correct, verify that your device is registered in /usr/local/etc/devd/nut-usb.conf. The vendor and product id can be found using:

# usbconfig -u 0 -a 2 dump_device_desc

where -u specifies the USB bus number and -a specifies the USB device index.

Information below may be currently obsolete, but the NUT project wishes it to become actual and factual again :)

NUT binary package built for Windows platform comes in a .msi file.

If you are using Windows 95, 98 or Me, you should install Windows Installer 2.0 from Microsoft site.

If you are using Windows 2000 or NT 4.0, you can download it here.

Newer Windows releases should include the Windows Installer natively.

Run NUT-Installer.msi and follow the wizard indications.

If you plan to use an UPS which is locally connected to an USB port, you have to install libUSB-win32 on your system. Then you must install your device via libusb’s "Inf Wizard".

If you have selected default directory, all configuration files are located in C:\Program Files\NUT\ups\etc

For suggestions about setting up the NUT build environment variants for Windows, please see link:docs/config-prereqs.txt and/or link:scripts/Windows/README.adoc files. Note this is rather experimental at this point.