According to this https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Terminal_Menu_Editing_During_Boot.html#sec-Booting_to_the_Debug_Shellto activate the debug shell only for this session, proceed as follows: add systemd.debug-shell at the end of the linux16 line after pressing e at the GRUB menu.However, this doesn't do anything for me. It just continues straight to Level 5 (the GUI). FWIW, I just have the following shell related lines in dmesg:$ dmesg | grep shell[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.10.0-327.36.3.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet LANG=en_GB.UTF-8 systemd.debug-shell[    0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-3.10.0-327.36.3.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet LANG=en_GB.UTF-8 systemd.debug-shellAny idea why I'm not booting to a shell?
Boot to shell - RHEL7
rhel;boot;systemd