Step Down Guide
1) Unlock your bootloader, using the toolkit or the manual way ( I like the manual way but whatever method you are comfortable with )
2) During confirmation of the unlock process the phone will reboot, enter settings and in developer options, uncheck usb debugging and check it again.
3) Now in Hasoons toolkit navigate to the commands area on the bottom of the screen and select erase cache
4) Next your going to flash recovery, I reccomend TWRP because it made rooting easy ( check the next steps ). While still in the bootloader screen select the TWRP recovery, disregard the first DOS screen ( only sends a command to reboot into bootloader ), hit the x to close it, the second screen will flash the recovery.
You should still be on the bootloader screen at this point
5) Erase the cache one more time, let the process finish
6) From the bootloader menu select Bootloader>Recovery, TWRP will now load up. Touch the reboot icon. TWRP will detect that you are not rooted and will push an install package apk for SuperSU
7) Once your phone has rebooted, open the install SuperSU app it will detect that you are not rooted and offer you two methods, you will be given an option to root the phone the normal way ( standard su install ) or download a TWRP flashable zip that will PERM-ROOT the HTC One. CHOOSE THE TWRP FLASHABLE ZIP.
Once you choose the TWRP flashable zip, the phone will reboot back into TWRP and flash the SU automatically. when the phone reboots you are all set.