Digging through a GUI settings panel for one obscure toggle wastes ten minutes you don't have, and gsettings gets you there from the terminal instead. You will finish with a repeatable way to discover a GSettings key, inspect its current value and valid range, make a reversible change, and watch for updates. The examples use gsettings 2.86.4 from Ubuntu package libglib2.0-bin 2.80.0-6ubuntu3.9.
Allow about fifteen minutes. You need a graphical desktop session or another session with a D-Bus session bus, plus an ordinary shell. Most commands are read-only and do not need sudo. The setting change itself is user-scoped, not a system administration task, and asking for elevated privileges will usually make the session mismatch worse.
Start by checking the installed command. This is an ordinary read-only check:
$ command -v gsettings
/usr/bin/gsettings
$ gsettings --version
2.86.4gsettings needs a D-Bus session bus when it writes to the dconf database. A command run from a text-only root shell, a scheduled job, or a different login session may therefore fail even though the same command works in your desktop terminal.
Checkpoint: continue only if the version prints and your shell belongs to the session whose settings you intend to inspect.
A schema groups related settings. List installed non-relocatable schemas, then list the keys in one schema:
$ gsettings list-schemas | head
org.gnome.desktop.a11y
org.gnome.desktop.a11y.applications
org.gnome.desktop.a11y.interface
org.gnome.desktop.a11y.keyboard
org.gnome.desktop.a11y.magnifier
$ gsettings list-keys org.gnome.desktop.interface | head
avatar-directories
can-change-accels
clock-format
clock-show-date
clock-show-secondsThe list depends on the installed desktop software, so do not copy a schema from another machine without checking it exists here. If a schema is relocatable, it needs a path as well as its ID: gsettings list-relocatable-schemas shows those schema IDs, and gsettings list-schemas --print-paths shows paths for fixed schemas.
For a larger discovery pass, gsettings list-recursively org.gnome.desktop.interface prints keys and values below the schema. Without a schema, list-recursively walks all schemas, which can produce a distracting amount of output. Add a schema first when you know the area you are investigating.
Use the interface schema's colour-scheme key as a harmless inspection example:
$ gsettings get org.gnome.desktop.interface color-scheme
'default'
$ gsettings range org.gnome.desktop.interface color-scheme
enum
'default'
'prefer-dark'
'prefer-light'
$ gsettings writable org.gnome.desktop.interface color-scheme
true
$ gsettings describe org.gnome.desktop.interface color-scheme
The preferred color scheme for the user interface. Valid values are "default", "prefer-dark", "prefer-light".The value printed by get is a serialised GVariant, not shell syntax, so a string comes back with its quotes intact. Boolean values print as true or false; lists and other types have their own GVariant notation. Read the range and description before constructing a value, rather than guessing from a key name.
Checkpoint: the exact output may differ if another application has changed the key. Treat your own get output as the baseline for any later undo.
Warning: this changes the appearance of the current user's desktop. Some applications notice immediately; others may need restarting. Record the original result from get before changing anything.
For a temporary dark theme preference, use a quoted GVariant string:
$ gsettings set org.gnome.desktop.interface color-scheme 'prefer-dark'
$ gsettings get org.gnome.desktop.interface color-scheme
'prefer-dark'The quotes around prefer-dark are part of the GVariant value; the outer shell quotes keep the value as one argument. Do not use an unquoted word for a string setting and do not add JSON syntax.
Undo this particular example by resetting the key to its schema default:
$ gsettings reset org.gnome.desktop.interface color-scheme
$ gsettings get org.gnome.desktop.interface color-scheme
'default'Reset is not a general backup mechanism. If the original value was a deliberate non-default, use gsettings set with the exact value you recorded instead. If the setting belongs to a relocatable schema, include its path in the schema argument, for example org.example.Schema:/some/path, after confirming that path is valid.
A key can exist but be locked by policy or otherwise unwritable. Test it before a script attempts a change:
schema='org.gnome.desktop.interface'
key='color-scheme'
if [ "$(gsettings writable "$schema" "$key")" != true ]; then
printf 'Not writable: %s %s
' "$schema" "$key" >&2
exit 1
fi
gsettings set "$schema" "$key" "'prefer-dark'"
gsettings get "$schema" "$key"Keep the schema and key as separate shell arguments. Quote values twice where needed: the shell must pass one argument, while the argument itself must contain the GVariant quotes required for a string. For production scripts, validate the exact value with range first and check the command's exit status: a non-zero result is a failure, not a signal to retry indefinitely.
No sudo belongs in this user-setting example. If a write fails because there is no session bus, repair the session context or run the command from the correct desktop login. Running it as root would target a different user's settings and may still have no usable session bus.
Use monitor when another application may be changing the setting:
$ gsettings monitor org.gnome.desktop.interface color-scheme
'prefer-dark'The process stays attached and prints changed values until you stop it with Ctrl-C. Omit the key to monitor every key in the schema. Start the monitor before reproducing the problem, then make one change at a time so the output has a clear cause. Monitoring does not modify the setting.
If the value keeps changing, check for a desktop extension, synchronisation tool, login script, or second settings application. The monitor tells you that a change happened; it does not identify the process that made it.
list-schemas and list-keys on the same machine.range; do not force a value outside the listed type or enum.set, or use reset only when the schema default is the intended state.get reports the desired value.gsettings version and session context.