You're going to need several applications for this, to install them run

# Ubuntu 14.04 and newer
sudo apt-get install xbindkeys xautomation x11-utils

or

# Before Ubuntu 14.04
sudo apt-get install xbindkeys xautomation xev

(xev was merged into x11utils, as of Ubuntu 14.04 or greater)

Step 1

You need to find the button numbers for the buttons on your mouse. Run xev. You will see a litle white windows appear, put your mouse in it and press your mouse buttons (it's best to do this one button at a time). You should get output like this for each button:

ButtonRelease event, serial 41, synthetic NO, window 0x4c00001,
root 0x2e9, subw 0x4c00002, time 25804905, (31,28), root:(821,80),
state 0x110, button 1, same_screen YES

(note: xev also capture mouse movement so you might need to sift through mouse movement events to find your button events; e.g.: xev -event mouse | grep Button --before-context=1 --after-context=2)

This is what is important from that output: button 1. That tells us that particular button is button one. I would store this in a .txt file for now.

Step 2

Create the xbindkeys config file using:

xbindkeys --defaults > $HOME/.xbindkeysrc  

Next we need to add the key/button bindings to the config file. You can open this file with gedit $HOME/.xbindkeysrc. This is where the fun begins. We are going to use xte to set bindings to our buttons.

To make a button act as Ctrl we would add:

"xte 'key Control_L'"
b:1  

This would bind Ctrl to mouse button one.

If you will tell me the button numbers of your buttons and what you want each to do, I will write the script for you.

The best answer in 2021 is the Key Mapper utility:
https://github.com/sezanzeb/key-mapper

No more hacking required.

I followed the @Seth's instructions, but the binding I wanted was to for the thumb button an the M705 to do CTRL + Left-click (for opening links in a new tab in chrome browser). The binding I needed to add was this:

"xte 'keydown Control_L' 'mouseclick 1' 'keyup Control_L'"
    b:10 + Release

It waits for the thumb button to be released, and then presses control key, performs the mouse click, then releases the control key.

For anyone who wants to bind copy and paste actions to mouse buttons:

1. Follow Seth answer (the one with Step 1, Step 2 and sudo apt-get install xbindkeys xautomation xev)
2. Put following lines in your .xbindkeysrc file:

This is for copying:

"xte 'keydown Control_L' 'key c' 'keyup Control_L'"
b:9

This is for pasting:

"xte 'keydown Control_L' 'key v' 'keyup Control_L'"
b:8

*b:9 means button 9 on the mouse (check button numbers with xev)

3. It won't work right away, you must reload .xbindkeysrc first or restart your machine.

You should install Solaar, a Linux tool that allows you to manage Logitech Unifying Receiver mice and keyboards, that comes with both a GUI and command line interface. To do that add the following repository and install by executing the following commands:

sudo add-apt-repository ppa:daniel.pavel/solaar

sudo apt-get update

sudo apt-get install solaar

This will allow you to increase and maximize you mouse's DPI, monitor battery, enable smooth scrolling and side scrolling. To get the multi window and zoom button working you can visit this site which walks you through the easy steps to get the functionality you are looking for:

http://www.ralf-oechsner.de/opensource/page/logitech_performance_mx

You should already have these as they should come with Ubuntu, but run this just in case.

sudo apt-get install libdaemon-dev libglade2-dev libgtk2.0-dev 

Now, download & install

1. btnx-config
2. btnx In this order.

To install:

Unzip, and cd into each of these folders.

In each of them run:

./configure
make
sudo make install

Once both of them are installed, run

sudo btnx-config

In Configurations tab, click Detect Mouse & Buttons

In Buttons tab, assign your mouse button a key or functionality. Make sure you ☑ check mark enabled.

Lastly, in Configurations tab, click on Restart btx button so your changes take effect.

I too have the g700s gaming mouse. The good news is that it was expensive (for a mouse) and the manufacture actually built it to a high standard. The functions for the mouse are stored in the mouse. The bad news is to configure it correctly you need to use the logitech software that only runs in windows.

So...basically you need to plug the mouse into a windows box, and configure it exactly how you want it. I'd recommend utilizing the switch profiles function so you can set it up good for normal usage, ie: running your linux desktop, compiz functions (switching apps, switching workspaces, toggling maximize, etc), and then make another profile for gaming (possibly with a different refresh rate) and the gaming buttons. As for compiz consider setting the 4 side thumbs buttons to alt, ctl, shift, superkey, as this will make using switching easier with the scroll wheel. alt + scroll wheel up becomes thumb button 1 + scroll wheel up.

My scheme:

thumb button 1 (forward lower) = alt

thumb button 2 (forward upper) = shift

thumb button 3 (rear lower) = ctrl

thumb button 4 (rear upper) = superkey (windows key)

index finger middle button = ctrl + alt + numpad 5

index finger closer to you = tab

index finger farther away from you = alt-f4 (compiz/linux/winX close app)

compiz defaults:

switch workspace = alt + ctl + mouse drag = lower 2 thumb buttons together + mouse click and drag; sounds complicated when typed it out but it's very efficient to use.

switch apps = alt + tab = lower thumb forward button + index finger closer button (remember for this to work well you need to keep holding down thumb button, so you can switch past 1 app)

fading a window (transparency) = alt + scroll wheel = thumb lower forward button + scroll wheel

Then go haul it back over to your linux box and it works perfectly.

The key bindings described above works great, but consider battlefield 4 also has a terrible time recognizing the mouse as a mouse with 10 buttons so for that I had to map my 4 thumb buttons to = , \ and ;. But obviously in linux this is silly, and to re-bind the = key to "next app" is a lesson in futility, especially when coding hahahaha.

MUCH NEEDED LINKS IF USING VIRTUALBOX TO RUN WINDOWS 7:

https://stackoverflow.com/questions/20021300/usb-devices-are-not-recognized-in-virtualbox-linux-host

https://www.youtube.com/watch?v=-0OyrvbZNwo

I have a Logitech MX 500 and wanted to map the lateral keys with Copy and Paste actions (it is very useful).

I used this guide to understand how to configure the xbindkeysrc file and be able to map the keys.

I made a solution that works with Wayland.

Its here https://github.com/mathportillo/wayland-mouse-mapper

It uses evemu to send a device event notice to the kernel, so it's not restricted by Wayland

A summarized bash script that show how it works is below (most of the commands require root privileges)

find your device:

libinput list-devices

to directly find your pointer device name use:

libinput list-devices | grep pointer -B3 | grep -o '/dev/input/event[1-9]*'

to list your device events use (change event5 to your pointer device name):

libinput debug-events --device /dev/input/event5

to bind commands to your device events use:

while read line; do
    echo ${line} # line represents a command
    # your code goes here
done < <(stdbuf -oL libinput debug-events --device /dev/input/event5 & )

to trigger a mouse event use:

evemu-event /dev/input/event5 --sync --type EV_KEY --code KEY_PAGEUP --value 1

type can be other than keystroke, and code can be other than PageUp, value is 1 for pressed and 0 for released yes, your mouse can trigger keystrokes, the system will interpret it the same as keyboards, its all just events from event devices.

A script that merge all the above concepts on a working mapper, that works on Wayland and can be configured as a service to start on system startup, can be found in the git repo above.

Scroll up and down with mouse forward and back buttons

First, install the required packages:

$ sudo apt install x11-utils xbindkeys xautomation

Next, use xev provided by x11-utils to detect the exact button numbers of the back and forward buttons of the mouse.

$ xev |grep -A2 ButtonPress

For my wired vertical Anker mouse, back and forward are respectively buttons 8 and 9.

ButtonPress event, serial 37, synthetic NO, window 0x3600001,
    root 0x1da, subw 0x0, time 1708382, (68,54), root:(939,498),
    state 0x10, button 8, same_screen YES
--
ButtonPress event, serial 37, synthetic NO, window 0x3600001,
    root 0x1da, subw 0x0, time 1711030, (69,48), root:(940,492),
    state 0x10, button 9, same_screen YES

Continue by creating a hidden file named .xbindkeysrc in your home directory with the following contents:

"xte 'keydown Down'"
b:8

"xte 'keyup Down'"
b:8 + Release

"xte 'keydown Up'"
b:9

"xte 'keyup Up'"
b:9 + Release

The xte command is provided by the xautomation package.

Finally, log out and in again from the desktop for these changes to take effect. You can now scroll up and down in browsers and other programs by pressing and holding the mouse back and forward buttons.