How to call desktop notifications on Ubuntu GNOME?

I was wondering how exactly one makes a desktop notification come up on Ubuntu GNOME 15.10 with GNOME 3.18? What I mean is how do I get one of these desktop notifications to come up with text that I have specified?:

It would be useful if I could execute a command or script that could do this so that I would be able to get notified about things in my system.

1 Answer

In the same way as also in GNOME 3.16 and in other desktop environments. The notifications can be sent via a notification daemon from the command line.

The command is part of the package libnotify-bin and is installed by the *-desktop meta-packages.

The dependencies are libc6, libglib2.0-0, libnotify4. Run strace to see the way of your notification:

% strace -e open notify-send foo bar
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libnotify.so.4", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libglib-2.0.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libgdk_pixbuf-2.0.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libgio-2.0.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libffi.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libpcre.so.3", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libz.so.1", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libresolv.so.2", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3

To send your own notification

notify-send foo bar

From man notify-send:

SYNOPSIS notify-send [OPTIONS] <summary> [body]
OPTIONS -u, --urgency=LEVEL Specifies the urgency level (low, normal, critical). -t, --expire-time=TIME The duration, in milliseconds, for the notification to appear on screen. (Ubuntu's Notify OSD and GNOME Shell both ignore this parameter.) -i, --icon=ICON[,ICON...] Specifies an icon filename or stock icon to display. -c, --category=TYPE[,TYPE...] Specifies the notification category. Help options: -?, --help Show this help message -h, --hint=TYPE:NAME:VALUE Specifies basic extra data to pass. Valid types are int, double, string and byte.