I've been meaning to get back to the original question for a couple of days, as I got sidetracked with talk about Timeshift, which is one of my passions (Can you tell? What gave it away?
)
Simplest (IMO) answer applies across all the Distros I use (90 or thereabouts) from 4 of the Linux families - RPM, Debian, Gentoo and Arch
Be at your Grub Menu, after booting, and before your timer runs out (10 seconds with some, and less with others, you can change it to what suits).
If you have only one Linux Distro and no Windows, your Grub Menu is hidden by default. You can bring it up at startup with the following:
- If your computer uses BIOS for booting, then hold down the Shift key while GRUB is loading to get the boot menu.
- If your computer uses UEFI for booting, press Esc several times while GRUB is loading to get the boot menu.
At the Grub Menu, down the bottom are options, choose 'e' for editing your startup parameters, you will be presented with maybe half a dozen lines, navigation is by arrow keys.
Possibly 2nd-bottom line will be one which starts with "linux" and mentions the Kernel, may be something like
4.9.0-11
or 5.2.1.xx
...whatever
Press End to go to the end of that line, and place a space, then
Type in
Press F10 to continue to boot.
You will be dropped into a shell, where the prompt may say
debian#
or
linuxmint#
or similar.
You are Root. It may take an enter or two to get to this prompt, some Distros print a message first and the cursor hangs.
Now type in and enter
and there will be output of maybe 30 lines, which includes your username.
This in itself is not a security risk, so I will print mine from Debian
chris@debian9dot8-MATE-SSD:~$ cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13
roxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-timesync:x:100:102:systemd Time Synchronization,,,:/run/systemd:/bin/false
systemd-network:x:101:103:systemd Network Management,,,:/run/systemd/netif:/bin/false
systemd-resolve:x:102:104:systemd Resolver,,,:/run/systemd/resolve:/bin/false
systemd-bus-proxy:x:103:105:systemd Bus Proxy,,,:/run/systemd:/bin/false
_apt:x:104:65534::/nonexistent:/bin/false
uuidd:x:105:109::/run/uuidd:/bin/false
dnsmasq:x:106:65534:dnsmasq,,,:/var/lib/misc:/bin/false
avahi-autoipd:x:107:110:Avahi autoip daemon,,,:/var/lib/avahi-autoipd:/bin/false
messagebus:x:108:111::/var/run/dbus:/bin/false
usbmux:x:109:46:usbmux daemon,,,:/var/lib/usbmux:/bin/false
speech-dispatcher:x:110:29:Speech Dispatcher,,,:/var/run/speech-dispatcher:/bin/false
rtkit:x:111:115:RealtimeKit,,,:/proc:/bin/false
lightdm:x:112:116:Light Display Manager:/var/lib/lightdm:/bin/false
pulse:x:113:117
ulseAudio daemon,,,:/var/run/pulse:/bin/false
avahi:x:114:119:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/bin/false
chris:x:1000:1000:chris,,,:/home/chris:/bin/bash
sshd:x:115:65534::/run/sshd:/usr/sbin/nologin
Debian-exim:x:116:120::/var/spool/exim4:/bin/false
I am doing this from a Debian session, so the first line does not show me as Root.
I have highlighted my username line, which will typically be in the last 5 - 6 lines, even the last.
Some Distros will show chris:x:1000 instead of 2 of the 1000, others chris:x:1000:1007 - etc, but all are similar.
I expect you will remember your username when you see it, even if it is
turkey_lurkey132eZZ
Yes?
Having established this, you can now reboot and type in your username at login.
For most, this is achieved with Ctrl-Alt-Del but some may require a hard reboot (power down, power up).
Before leaving you, at the OP:
You must have done a good number on your Manjaro to get to this point. All Manjaro, and almost all other Distros, have your username appear by default at the login. Kali and Debian itself are two notable exceptions.
Which leads us back to Timeshift.
Wizard