Root with (easier) CF-Auto + script or with Android SDK then launch ./android and install platform-tools
See if the phone is connected
adb devices
List of devices attached xxxxx recovery
If you have
List of devices attached ???????????? no permissions
Do
sudo ./adb kill-server sudo ./adb start-server
Reboot in bootloader mode
adb reboot bootloader
See if the phone is connected during the boot (you must be root under linux)
sudo ./fastboot devices
Unlock the bootloader
sudo ./fastboot oem unlock
Flash in recovery mode
fastboot flash recovery twrp-file-name.img
Stock (not many features, autonony is bad)
Slim Bean (good performance, many feature, dark mode, autonomy not bad).
PSX (very good performance by default, no dark mode, need clockWorkMode recovery to install, TWRT does not work for this rom)
BeanStalk (good performance, quite good, no dark mode)
Cyanogen (good performance, missed some feature, no dark mode)
Franco (good autonomy)
Bricked (very good performance, good autonomy)
Chaos (good performance, good autonomy)
ElemantalX (good performance, good autonomy)
Faux (not working)
Best : Bricked Kernel (best performance 20000 on Quadrant (with custom dalvik), 32000 on Antutu) and not bad on autonomy
Use custom dalvik (http://forum.xda-developers.com/showthread.php?t=2546120)
http://androidforums.com/nexus-5-all-things-root/776309-nexus-5-all-things-root-guide.html
http://www.gizmodo.fr/2013/11/09/comment-rooter-google-nexus-5.html
http://androidforums.com/nexus-5-all-things-root/790362-nexus-5-rooting-guide.html