NewLinuxInfo

Guides, Info & Tips on New Modern Linux Server Administration

Basic Linux System Commands - System Management

TMUX - Terminal Multiplexer

TMUX is what I consider one of the most invaluable tools when it comes to managing and administering Linux servers from the command line. Among it's many features is it's ability to keep your shell connection running in the event of beding disconnected from a remote SSH session. If used properly, it allows you to reconnect to your SSH session you had running, along with whatever applicatoins, scripts, etc, you had running, without losing a beat! It's really handhy to be able to reconnect to a remote session that was inadvertently disconnected! TMUX has saved my butt many times over the years! It also can be used to open multiple shell connections all in the same window, allowing you to split one terminal into two, four, and so on! Plus, you can share the terminal with other remote users, so they can see waht you are typing, and they can also type and you control the same shell! That comes in very handy when you need to show someone how to do something within a shell.

Here is the very simple installation process on a Red Hat based distribution, on Rocky Linux 9.2:

[jamie@rocky9vm32.dawgland.com:~]$ sudo dnf install tmux
Last metadata expiration check: 1:30:38 ago on Thu 05 Oct 2023 12:25:59 AM PDT.
Dependencies resolved.
================================================================================
 Package        Architecture     Version                 Repository        Size
================================================================================
Installing:
 tmux           x86_64           3.2a-4.el9              baseos           474 k

Transaction Summary
================================================================================
Install  1 Package

Total download size: 474 k
Installed size: 1.1 M
Is this ok [y/N]: y
Downloading Packages:
tmux-3.2a-4.el9.x86_64.rpm                      612 kB/s | 474 kB     00:00    
--------------------------------------------------------------------------------
Total                                           270 kB/s | 474 kB     00:01     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Installing       : tmux-3.2a-4.el9.x86_64                                 1/1 
  Running scriptlet: tmux-3.2a-4.el9.x86_64                                 1/1 
  Verifying        : tmux-3.2a-4.el9.x86_64                                 1/1 

Installed:
  tmux-3.2a-4.el9.x86_64                                                        

Complete!
[jamie@rocky9vm32.dawgland.com:~]$

Using TMUX

Using TMUX is as simple as just typing it's name. It will change the color and look of your prompt to indicate it's running.

System Power Off & Reboot

The "shutdown" command has a number of arguments that control how it behaves, such as shutting completely down, or rebooting, with options to send system-wide broadcast messages to all logged in users, apply a delay before shutting down, and other options.

For a simple quick reboot, the alias "reboot" causes an immediate shutdown and startup, resulting in a reboot, hence the name of the command!

As with most all system control commands, you must have eleveated privilges to be the root user, or a memeber of the correct group to allow for usage of sudo to run commands as the root, aka, superuser/administrator. So, as the root user, just typing "reboot" from the command line causes in immediate system reboot without warning or options! If you are not logged in as the root user, then using sudo, assuming you are in the corect sudoers group, to allow you to run the command as if you were logged in as the root user. The command "sudo reboot" then causes an immediate reboot without warning.

The real command to shutdown and reboot the system is the "shutdown" command, with appropriate switches and/or arguments. For instance, to reboot the system now, just as before, but using the shutdown command, the full command to reboot using the shutdown command is as follows:

[jamie@rocky9vm35.dawgland2.com:~]$ sudo shutdown -r now
[jamie@rocky9vm35.dawgland2.com:~]$ Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

To shut down a system completely, without starting it back up, instead of using the "-r" switch without the quotes, as in the previous example, you use the "-h" switch, without the quotes, as in this example:

[jamie@rocky9vm35.dawgland2.com:~]$ sudo shutdown -h now
[jamie@rocky9vm35.dawgland2.com:~]$ Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

To add a time deley to the shutdown command, so as to allow logged in userrs to have time to log out cleanly, modify the command as follows to include a 30 second time delay before actually shutting down, as show here:

[jamie@rocky9vm35.dawgland2.com:~]$ sudo shutdown -h -t 30
Shutdown scheduled for Mon 2023-09-11 19:15:53 PDT, use 'shutdown -c' to cancel.
[jamie@rocky9vm35.dawgland2.com:~]$ Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

Users logged into the same machine will see messages similiar to this when a time delay is given to the shutdown command:

[jamie@rocky9vm35.dawgland2.com:~]$ 
Broadcast message from root@rocky9vm35.dawgland2.com on pts/0 (Mon 2023-09-11 19:14:53 PDT):

The system will power off at Mon 2023-09-11 19:15:53 PDT!


Broadcast message from root@rocky9vm35.dawgland2.com on pts/0 (Mon 2023-09-11 19:15:53 PDT):

The system will power off now!

Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

And last, but certently not lease, here is an example to reboot a system in ONE minute, while broadcasting a custom message to all logged on users:

[jamie@rocky9vm35.dawgland2.com:~]$ sudo shutdown -r +1 "This Server, Rocky9VM35, will be going down in ONE MINUTE for a quick reboot. Please finish up your work and log off immediatelly!"

This produces these messages in the terminal that called the command:

Reboot scheduled for Mon 2023-09-11 19:33:46 PDT, use 'shutdown -c' to cancel.
[jamie@rocky9vm35.dawgland2.com:~]$ Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

Other users logged into the same system will receive messages similar to these:

[jamie@rocky9vm35.dawgland2.com:~]$ 
Broadcast message from root@rocky9vm35.dawgland2.com on pts/0 (Mon 2023-09-11 19:32:46 PDT):

This Server, Rocky9VM35, will be going down in ONE MINUTE for a quick reboot. Please finish up your work and log off immediatelly!
The system will reboot at Mon 2023-09-11 19:33:46 PDT!


Broadcast message from root@rocky9vm35.dawgland2.com on pts/0 (Mon 2023-09-11 19:33:46 PDT):

This Server, Rocky9VM35, will be going down in ONE MINUTE for a quick reboot. Please finish up your work and log off immediatelly!
The system will reboot now!

Connection to rocky9vm35 closed by remote host.
Connection to rocky9vm35 closed.

systemctl

Query Service Status

For instance, here is an example of systemctl being used to query the Secure Shell Server(SSH):

[root@fc24 ~]# systemctl status sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor pres
   Active: active (running) since Sun 2016-09-11 01:12:21 PDT; 1h 20min ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 791 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCE
 Main PID: 810 (sshd)
    Tasks: 1 (limit: 512)
   CGroup: /system.slice/sshd.service
           └─810 /usr/sbin/sshd

Sep 11 01:12:20 fc24.dawgland.com systemd[1]: Starting OpenSSH server daemon.
Sep 11 01:12:21 fc24.dawgland.com systemd[1]: sshd.service: PID file /var/run
Sep 11 01:12:21 fc24.dawgland.com sshd[810]: Server listening on 0.0.0.0 port
Sep 11 01:12:21 fc24.dawgland.com systemd[1]: Started OpenSSH server daemon.
lines 1-15/15 (END)

Stopping a Service

This is what is looks like after stopping the SSH server:

[root@fc24 ~]# systemctl stop sshd.service
[root@fc24 ~]# systemctl status sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor pres
   Active: inactive (dead) since Sun 2016-09-11 02:38:55 PDT; 10s ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 791 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCE
 Main PID: 810 (code=exited, status=0/SUCCESS)

Sep 11 01:12:20 fc24.dawgland.com systemd[1]: Starting OpenSSH server daemon.
Sep 11 01:12:21 fc24.dawgland.com systemd[1]: sshd.service: PID file /var/run
Sep 11 01:12:21 fc24.dawgland.com sshd[810]: Server listening on 0.0.0.0 port
Sep 11 01:12:21 fc24.dawgland.com systemd[1]: Started OpenSSH server daemon.
Sep 11 02:38:55 fc24.dawgland.com systemd[1]: Stopping OpenSSH server daemon.
Sep 11 02:38:55 fc24.dawgland.com systemd[1]: Stopped OpenSSH server daemon.
lines 1-14/14 (END)

Starting a Service Back Up

And this is the command to start it back up, and because there is no output after starting it, I've also included the output of the status once again after starting the Secure Shell Server back up:

[root@fc24 ~]# systemctl start sshd.service
[root@fc24 ~]# systemctl status sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor pres
   Active: active (running) since Sun 2016-09-11 02:42:38 PDT; 9s ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 2801 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCC
 Main PID: 2803 (sshd)
    Tasks: 1 (limit: 512)
   CGroup: /system.slice/sshd.service
           └─2803 /usr/sbin/sshd

Sep 11 02:42:38 fc24.dawgland.com systemd[1]: Starting OpenSSH server daemon.
Sep 11 02:42:38 fc24.dawgland.com systemd[1]: sshd.service: PID file /var/run
Sep 11 02:42:38 fc24.dawgland.com sshd[2803]: Server listening on 0.0.0.0 por
Sep 11 02:42:38 fc24.dawgland.com systemd[1]: Started OpenSSH server daemon.
lines 1-15/15 (END)

Disabling a Service

To Disable a service, usually replacing status, start, or stop with "disable" works to disable most services, but sometimes, it doesn't always work, and you also need to "mask" the service as well.

Using Mask to Forcefully Disable a Service

This proved to be the case with the RPCBIND.service. After stopping and disabling the service, a reboot caused the service to be re-enabled and started back up. To have the service disabled and that state saved after a reboot, the "mask" argument is given to the systemctl command. For instance, in the case of RPCBIND.service, this is how to disable it:
(In the below example, ONLY the 3 commands starting with systemctl are typed by the root superuser)

[root@vm1 ~]# systemctl stop rpcbind.service
Warning: Stopping rpcbind.service, but it can still be activated by:
  rpcbind.socket
[root@vm1 ~]# systemctl disable rpcbind.service
[root@vm1 ~]# systemctl mask rpcbind.service
ln -s '/dev/null' '/etc/systemd/system/rpcbind.service

Changing the Default Run Level the Systemd Way

To change the default run-level from booting up into the Graphical User Interface(GUI) into straight text multi-user, which is preferable on a server, the old method involved editing the /etc/inittab file changing the default runlevel from 5 to 3, as shown here:

id:3:initdefault:

On modern RPM based systems, this has been replaced by using the systemctl command to create/change the symlink /etc/systemd/system/default.target to point to /lib/systemd/multi-user.target, and visa-versa to switch back to the GUI bootup mode. This can be done manually using the shell "ln -sf" symlink creation command, or more easily, and more importantly, more standardized with the systemctl command, as shown here. The following 3 commands show how to first check the default runlevel target, then change it from graphical to text-based multi-user, and then the 3rd command show's confirmation the command was successful.

[root@fc21 ~]# systemctl get-default
graphical.target
[root@fc21 ~]# systemctl set-default multi-user.target
Removed symlink /etc/systemd/system/default.target.
Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/multi-user.target.
[root@fc21 ~]# systemctl get-default
multi-user.target

dnf

Another BIG change to a "more modern" way of managing all of the software packages on your Linux machine, is the dnf command that is a direct drop-in replacement for yum, the old, tried and true RPM package manager that for going on 20 years has been the main interface to manage Linux software installations, taking into account all of the required dependencies, as well as uninstalling, more commonly referred to "removing" software packages.

Here is an example of how to use dnf to first search for, and then install over the internet, Blender, a very powerful tool to create your own custom animation, simulations and movies:

[root@fc24 ~]# dnf search blender
Last metadata expiration check: 2:29:11 ago on Sun Sep 11 00:31:02 2016.
=========================== N/S Matched: blender ============================
blender.x86_64 : 3D modeling, animation, rendering and post-production

After searching for and finding the package I want to install, I then use dnf, NOT YUM!, to perform the dependency checking, downloading of the package along with the required dependencies, install all of the packages, and then perform what is called the "Cleanup" portion of the process.

This is how to use dnf to download, install, and then clean up any left over junk:

[root@fc24 ~]# dnf install blender
Last metadata expiration check: 2:30:45 ago on Sun Sep 11 00:31:02 2016.
Dependencies resolved.
=============================================================================
 Package                      Arch      Version             Repository  Size
=============================================================================
Installing:
 Field3D                      x86_64    1.7.2-1.fc24        updates    519 k
 OpenColorIO                  x86_64    1.0.9-11.fc24       fedora     439 k
 OpenImageIO                  x86_64    1.6.16-1.fc24       updates    1.7 M
 blender                      x86_64    1:2.77a-1.fc24      updates     29 M
 boost-locale                 x86_64    1.60.0-7.fc24       updates    279 k
 boost-program-options        x86_64    1.60.0-7.fc24       updates    166 k
 boost-regex                  x86_64    1.60.0-7.fc24       updates    300 k
 fftw-libs-double             x86_64    3.3.4-7.fc24        fedora     805 k
 fonts-blender                noarch    1:2.77a-1.fc24      updates    4.7 M
 google-droid-sans-fonts      noarch    20120715-10.fc24    fedora     2.5 M
 hdf5                         x86_64    1.8.16-3.fc24       fedora     1.7 M
 jack-audio-connection-kit    x86_64    1.9.10-5.fc24       fedora     555 k
 jemalloc                     x86_64    4.2.1-1.fc24        updates    182 k
 libffado                     x86_64    2.2.1-8.fc24        fedora     690 k
 libspnav                     x86_64    0.2.3-3.fc24        fedora      17 k
 libxml++                     x86_64    2.40.1-2.fc24       fedora      89 k
 pugixml                      x86_64    1.7-2.fc24          fedora      92 k
 python3-numpy                x86_64    1:1.11.0-4.fc24     fedora     3.0 M
 tinyxml                      x86_64    2.6.2-11.fc24       fedora      54 k
 yaml-cpp03                   x86_64    0.3.0-9.fc24        fedora     151 k

Transaction Summary
=============================================================================
Install  20 Packages

Total download size: 47 M
Installed size: 178 M
Is this ok [y/N]: y

Red Hat Enterprise Linux 5,6 & 7 - Common Administrative Command Cheat Sheets

Here are some very nice printable cheat sheets of the most common Red Hat Enterprise Linux administrative commands:
RedHatEnterpriseLinux_5_6_7_Cheatsheets.pdf

File System Tools & Utilities

There are hundreds if not thousands of file system tools, utilities and apps, so here I will try to go over the main, best, and most useful file system tools in my opinion. This section will have to be a "work in progress", and I will add to this section as time permites, as I find myself needing to use these applilcations.

ALL of these tools and utilities must be ran as either the root superuser, or using the "sudo" prefix!

GDISK - The More Modern Disk Partitioning Tool with Support for GPT Partition Tables!!!

GDISK is a Linux command-line tool used to modify a GPT-Style partition table. The tool functions almost identically to it's old-school counterpart, FDISK, and uses almost identical commands.

The greatest advantage of using GDISK, besides being able tobe used on GPT partition tqables, is it's ability to create and manage more thanjust 4 primary partitions, as FDISK is limmited to. The other main difference is the usages of larger/longer hex-codes to differentiate different file-system types. For instance, the standard Linux filesystem type is specified bvy the hex code 0x83, or just 83, whereas using the GPT partitions table type, that same Linux basic filesystem type is identified with the hex code of 8300.

ALL GPT FILESYSTEM TYPES

0100 Microsoft basic data “FAT-12”
0400 Microsoft basic data “FAT-16 < 32M”
0600 Microsoft basic data “FAT-16”
0700 Microsoft basic data “NTFS (or HPFS)”
0701 Microsoft Storage Replica
0702 ArcaOS Type 1
0b00 Microsoft basic data “FAT-32”
0c00 Microsoft basic data “FAT-32 LBA”
0c01 Microsoft reserved
0e00 Microsoft basic data “FAT-16 LBA”
1100 Microsoft basic data “Hidden FAT-12”
1400 Microsoft basic data “Hidden FAT-16 < 32M”
1600 Microsoft basic data “Hidden FAT-16”
1700 Microsoft basic data “Hidden NTFS (or HPFS)”
1b00 Microsoft basic data “Hidden FAT-32”
1c00 Microsoft basic data “Hidden FAT-32 LBA”
1e00 Microsoft basic data “Hidden FAT-16 LBA”
2700 Windows RE
3000 ONIE boot
3001 ONIE config
3900 Plan 9
4100 PowerPC PReP boot
4200 Windows LDM data
4201 Windows LDM metadata
4202 Windows Storage Space
7501 IBM GPFS
7f00 ChromeOS kernel
7f01 ChromeOS root
7f02 ChromeOS reserved
7f03 ChromeOS firmware
7f04 ChromeOS mini-OS
7f05 ChromeOS hibernate
8200 Linux swap
8300 Linux filesystem
8301 Linux reserved
8302 Linux /home
8303 Linux x86 root (/)
8304 Linux x86-64 root (/)
8305 Linux ARM64 root (/)
8306 Linux /srv
8307 Linux ARM32 root (/)
8308 Linux dm-crypt
8309 Linux LUKS
830a Linux IA-64 root (/)
830b Linux x86 root verity
830c Linux x86-64 root verity
830d Linux ARM32 root verity
830e Linux ARM64 root verity
830f Linux IA-64 root verity
8310 Linux /var
8311 Linux /var/tmp
8312 Linux user’s home
8313 Linux x86 /usr
8314 Linux x86-64 /usr
8315 Linux ARM32 /usr
8316 Linux ARM64 /usr
8317 Linux IA-64 /usr
8318 Linux x86 /usr verity
8319 Linux x86-64 /usr verity
831a Linux ARM32 /usr verity
831b Linux ARM64 /usr verity
831c Linux IA-64 /usr verity
831d Linux Alpha root (/)
831e Linux ARC root (/)
831f Linux LoongArch root (/)
8320 Linux MIPS-32 BE root (/)
8321 Linux MIPS-64 BE root (/)
8322 Linux MIPS-32 LE root (/)
8323 Linux MIPS-64 LE root (/)
8324 Linux PA-RISC root (/)
8325 Linux PowerPC-32 root (/)
8326 Linux PowerPC-64 BE root (/)
8327 Linux PowerPC-64 LE root (/)
8328 Linux RISC-V-32 root (/)
8329 Linux RISC-V-64 root (/)
832a Linux s390 root (/)
832b Linux s390x root (/)
832c Linux TILE-Gx root (/)
832d Linux Alpha /usr
832e Linux ARC /usr
832f Linux LoongArch /usr
8330 Linux MIPS-32 BE /usr
8331 Linux MIPS-64 BE /usr
8332 Linux MIPS-32 LE /usr
8333 Linux MIPS-64 LE /usr
8334 Linux PA-RISC /usr
8335 Linux PowerPC-32 /usr
8336 Linux PowerPC-64 BE /usr
8337 Linux PowerPC-64 LE /usr
8338 Linux RISC-V-32 /usr
8339 Linux RISC-V-64 /usr
833a Linux s390 /usr
833b Linux s390x /usr
833c Linux TILE-Gx /usr
833d Linux Alpha root verity
833e Linux ARC root verity
833f Linux LoongArch root verity
8340 Linux MIPS-32 BE root verity
8341 Linux MIPS-64 BE root verity
8342 Linux MIPS-32 LE root verity
8343 Linux MIPS-64 LE root verity
8344 Linux PA-RISC root verity
8345 Linux PowerPC-64 LE root verity
8346 Linux PowerPC-64 BE root verity
8347 Linux PowerPC-32 root verity
8348 Linux RISC-V-32 root verity
8349 Linux RISC-V-64 root verity
834a Linux s390 root verity
834b Linux s390x root verity
834c Linux TILE-Gx root verity
834d Linux Alpha /usr verity
834e Linux ARC /usr verity
834f Linux LoongArch /usr verity
8350 Linux MIPS-32 BE /usr verity
8351 Linux MIPS-64 BE /usr verity
8352 Linux MIPS-32 LE /usr verity
8353 Linux MIPS-64 LE /usr verity
8354 Linux PA-RISC /usr verity
8355 Linux PowerPC-64 LE /usr verity
8356 Linux PowerPC-64 BE /usr verity
8357 Linux PowerPC-32 /usr verity
8358 Linux RISC-V-32 /usr verity
8359 Linux RISC-V-64 /usr verity
835a Linux s390 /usr verity
835b Linux s390x /usr verity
835c Linux TILE-Gx /usr verity
835d Linux Alpha root verity signature
835e Linux ARC root verity signature
835f Linux ARM32 root verity signature
8360 Linux ARM64 root verity signature
8361 Linux IA-64 root verity signature
8362 Linux LoongArch root verity signature
8363 Linux MIPS-32 BE root verity signature
8364 Linux MIPS-64 BE root verity signature
8365 Linux MIPS-32 LE root verity signature
8366 Linux MIPS-64 LE root verity signature
8367 Linux PA-RISC root verity signature
8368 Linux PowerPC-64 LE root verity signature
8369 Linux PowerPC-64 BE root verity signature
836a Linux PowerPC-32 root verity signature
836b Linux RISC-V-32 root verity signature
836c Linux RISC-V-64 root verity signature
836d Linux s390 root verity signature
836e Linux s390x root verity signature
836f Linux TILE-Gx root verity signature
8370 Linux x86-64 root verity signature
8371 Linux x86 root verity signature
8372 Linux Alpha /usr verity signature
8373 Linux ARC /usr verity signature
8374 Linux ARM32 /usr verity signature
8375 Linux ARM64 /usr verity signature
8376 Linux IA-64 /usr verity signature
8377 Linux LoongArch /usr verity signature
8378 Linux MIPS-32 BE /usr verity signature
8379 Linux MIPS-64 BE /usr verity signature
837a Linux MIPS-32 LE /usr verity signature
837b Linux MIPS-64 LE /usr verity signature
837c Linux PA-RISC /usr verity signature
837d Linux PowerPC-64 LE /usr verity signature
837e Linux PowerPC-64 BE /usr verity signature
837f Linux PowerPC-32 /usr verity signature
8380 Linux RISC-V-32 /usr verity signature
8381 Linux RISC-V-64 /usr verity signature
8382 Linux s390 /usr verity signature
8383 Linux s390x /usr verity signature
8384 Linux TILE-Gx /usr verity signature
8385 Linux x86-64 /usr verity signature
8386 Linux x86 /usr verity signature
8400 Intel Rapid Start
8401 SPDK block device
8500 Container Linux /usr
8501 Container Linux resizable rootfs
8502 Container Linux /OEM customization
8503 Container Linux root on RAID
8e00 Linux LVM
a000 Android bootloader
a001 Android bootloader 2
a002 Android boot
a003 Android recovery
a004 Android misc
a005 Android metadata
a006 Android system
a007 Android cache
a008 Android data
a009 Android persistent
a00a Android factory
a00b Android fastboot/tertiary
a00c Android OEM
a00d Android vendor
a00e Android config
a00f Android factory (alt)
a010 Android meta
a011 Android EXT
a012 Android SBL1
a013 Android SBL2
a014 Android SBL3
a015 Android APPSBL
a016 Android QSEE/tz
a017 Android QHEE/hyp
a018 Android RPM
a019 Android WDOG debug/sdi
a01a Android DDR
a01b Android CDT
a01c Android RAM dump
a01d Android SEC
a01e Android PMIC
a01f Android misc 1
a020 Android misc 2
a021 Android device info
a022 Android APDP
a023 Android MSADP
a024 Android DPO
a025 Android recovery 2
a026 Android persist
a027 Android modem ST1
a028 Android modem ST2
a029 Android FSC
a02a Android FSG 1
a02b Android FSG 2
a02c Android SSD
a02d Android keystore
a02e Android encrypt
a02f Android EKSST
a030 Android RCT
a031 Android spare1
a032 Android spare2
a033 Android spare3
a034 Android spare4
a035 Android raw resources
a036 Android boot 2
a037 Android FOTA
a038 Android system 2
a039 Android cache
a03a Android user data
a03b LG (Android) advanced flasher
a03c Android PG1FS
a03d Android PG2FS
a03e Android board info
a03f Android MFG
a040 Android limits
a200 Atari TOS basic data
a500 FreeBSD disklabel
a501 FreeBSD boot
a502 FreeBSD swap
a503 FreeBSD UFS
a504 FreeBSD ZFS
a505 FreeBSD Vinum/RAID
a506 FreeBSD nandfs
a580 Midnight BSD data
a581 Midnight BSD boot
a582 Midnight BSD swap
a583 Midnight BSD UFS
a584 Midnight BSD ZFS
a585 Midnight BSD Vinum
a600 OpenBSD disklabel
a800 Apple UFS
a900 FreeBSD disklabel “NetBSD partition types. Note that the main entry sets it up as a FreeBSD disklabel. I’m not 100% certain this is the correct behavior.”
a901 NetBSD swap
a902 NetBSD FFS
a903 NetBSD LFS
a904 NetBSD concatenated
a905 NetBSD encrypted
a906 NetBSD RAID
ab00 Recovery HD
af00 Apple HFS/HFS+
af01 Apple RAID
af02 Apple RAID offline
af03 Apple label
af04 AppleTV recovery
af05 Apple Core Storage
af06 Apple SoftRAID Status
af07 Apple SoftRAID Scratch
af08 Apple SoftRAID Volume
af09 Apple SoftRAID Cache
af0a Apple APFS
af0b Apple APFS Pre-Boot
af0c Apple APFS Recovery
b000 U-Boot boot loader
b300 QNX6 Power-Safe
bb00 Barebox boot loader
bc00 Acronis Secure Zone
be00 Solaris boot
bf00 Solaris root
bf01 Solaris /usr & Mac ZFS
bf02 Solaris swap
bf03 Solaris backup
bf04 Solaris /var
bf05 Solaris /home
bf06 Solaris alternate sector
bf07 Solaris Reserved 1
bf08 Solaris Reserved 2
bf09 Solaris Reserved 3
bf0a Solaris Reserved 4
bf0b Solaris Reserved 5
c001 HP-UX data
c002 HP-UX service
e100 ONIE boot
e101 ONIE config
e900 Veracrypt data
ea00 Freedesktop $BOOT
eb00 Haiku BFS
ed00 Sony system partition
ed01 Lenovo system partition
ef00 EFI System
ef01 MBR partition scheme
ef02 BIOS boot partition
f100 Fuchsia boot loader (slot A/B/R)
f101 Fuchsia durable mutable encrypted system data
f102 Fuchsia durable mutable boot loader
f103 Fuchsia factory ro system data
f104 Fuchsia factory ro bootloader data
f105 Fuchsia Volume Manager
f106 Fuchsia verified boot metadata (slot A/B/R)
f107 Fuchsia Zircon boot image (slot A/B/R)
f108 Fuchsia ESP
f109 Fuchsia System
f10a Fuchsia Data
f10b Fuchsia Install
f10c Fuchsia Blob
f10d Fuchsia FVM
f10e Fuchsia Zircon boot image (slot A)
f10f Fuchsia Zircon boot image (slot B)
f110 Fuchsia Zircon boot image (slot R)
f111 Fuchsia sys-config
f112 Fuchsia factory-config
f113 Fuchsia bootloader
f114 Fuchsia guid-test
f115 Fuchsia verified boot metadata (A)
f116 Fuchsia verified boot metadata (B)
f117 Fuchsia verified boot metadata (R)
f118 Fuchsia misc
f119 Fuchsia emmc-boot1
f11a Fuchsia emmc-boot2
f800 Ceph OSD
f801 Ceph dm-crypt OSD
f802 Ceph journal
f803 Ceph dm-crypt journal
f804 Ceph disk in creation
f805 Ceph dm-crypt disk in creation
f806 Ceph block
f807 Ceph block DB
f808 Ceph block write-ahead log
f809 Ceph lockbox for dm-crypt keys
f80a Ceph multipath OSD
f80b Ceph multipath journal
f80c Ceph multipath block 1
f80d Ceph multipath block 2
f80e Ceph multipath block DB
f80f Ceph multipath block write-ahead log
f810 Ceph dm-crypt block
f811 Ceph dm-crypt block DB
f812 Ceph dm-crypt block write-ahead log
f813 Ceph dm-crypt LUKS journal
f814 Ceph dm-crypt LUKS block
f815 Ceph dm-crypt LUKS block DB
f816 Ceph dm-crypt LUKS block write-ahead log
f817 Ceph dm-crypt LUKS OSD
fb00 VMWare VMFS
fb01 VMWare reserved
fc00 VMWare kcore crash partition
fd00 Linux RAID
“Note: DO NOT use the 0xffff code; that’s reserved to indicate an unknown GUID type code.”

Here's where this list came from:
https://www.toomanyatoms.com/computer/gdisk_gpt_partition_codes.html

FDISK - The Original Old-School Partitioning Tool

fdisk, the disk partitionling command-line tool, as are all Linux command line commands, Case Sensitive, and therefore always lower case! fdisk doesn't always need switches, but ALWAYS MUST have arguments! In the case of fdisk, the most common switch is the "l" switch, a lower-case L. It's used to only LIST, and NOT change/modify any disk partitions. The "l" switch spits out the current partition pointed to with the argument, which is always a Linux "device" file, such as "/dev/sda", case sensitive, without the quotes. /dev/sda is the first hard drive, with the "s" part referring to the old SCSI protocol. Therefore, /dev/sda referres to SCSI device A, the first drive in a Linux system. The next drive would be /dev/sdb, the third drive would be /dev/sdc, and so on.

On more modern systems, that don't use old-school hard drives, the newest technology drives used for storage, especially on laptops, are M.1 drives, which are solid-state drives which usually use the NVMe standard, making the device files for those drives something like /dev/nvme01p0, or similar. CD & DVD writers(also referred to "burners"), often use "/dev/sr0" as the first CD/DVD burner on a system, which stand for "SCSI Recorder Number 0", since numbering usually starts with 0 on computer systems.

Regardless of the device files being used, the "fdisk" commands are all basically the same, other than the actual device you are partitionling, which is CRITICAl, as there is NO going back once you have partitioned and written that partion table to the drive!!! Therefore, you MUST ALWAYS be 100% CERTAIN you are using the correct hard of solid-state drive file!!!

One more BIG concern to take into account is if the disk already has an existing partion table created, from being previously used, you MUST be sure to use the CORRECT disk partitioning tools, as newer, larger and more modern computers use the new disk partitioning tool called GDISK, instead of FDISK! Both are used with all Lower Case letters(fdis & gdisk), but if there is already a "gdisk" partioned disk, known as a "GPT" partition table, you MUST use the "gdisk" tool to make any changes/modification to the disk's partition table, and visa versa in the case of a disk with an existing "fdisk" partion table, known as the "DOS" partition table type. It usually shows as all lower-case, such as "dos".

Usesage of both partitioning tools are almost identicle, with the only real differences being the partition type hex-codes used to define the partition types at creation time.

The first step is the unmount the USB flash drive, before using any partitioning tools, as it can otherwise corrupt the drive. Because I am using an existing 256GB USB 3.0 flash drive, I prefer to use the udiskctl utility to both unmount and power-off USB flash drives. Here is the command I use to "unmount" the drive, before making any changes to it's partition table:

[root@server.dawgland.com:~]# udisksctl unmount -b /dev/sdl
Unmounted /dev/sdl.
[root@server.dawgland.com:~]#

Next, I need to use the fdisk tool to delete the existing partitions on the USB flash drive:

[root@server.dawgland.com:~]# fdisk /dev/sdl

Welcome to fdisk (util-linux 2.35.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

The device contains 'exfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

Command (m for help): p

Disk /dev/sdl: 234.38 GiB, 251658240000 bytes, 491520000 sectors
Disk model: ProductCode     
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot      Start        End    Sectors  Size Id Type
/dev/sdl1       4294967295 8589934589 4294967295    2T ff BBT
/dev/sdl2       4294967295 8589934589 4294967295    2T ff BBT
/dev/sdl3       4294967295 8589934589 4294967295    2T ff BBT
/dev/sdl4       4294967295 5035196669  740229375  353G ff BBT

Command (m for help): d
Partition number (1-4, default 4): 

Partition 4 has been deleted.

Command (m for help): d
Partition number (1-3, default 3): 

Partition 3 has been deleted.

Command (m for help): d
Partition number (1,2, default 2): 

Partition 2 has been deleted.

Command (m for help): d
Selected partition 1
Partition 1 has been deleted.

Command (m for help): p
Disk /dev/sdl: 234.38 GiB, 251658240000 bytes, 491520000 sectors
Disk model: ProductCode     
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@server.dawgland.com:~]#

I like to manually run the "sync" command a couple of times just to make sure the disks are all synced up! Here's is me doing so:

[root@server.dawgland.com:~]# sync
[root@server.dawgland.com:~]# sync
[root@server.dawgland.com:~]# sync
[root@server.dawgland.com:~]#

I then use the "fdisk" tool again to view my changes. As can be seen, although the 4 partitions had vanished, as intended, it still shows the deives contains an 'exfat' signature, and althoug it states it will be removed by a "write" command, doing the "w" command does NOT remove the 'exfat' signature, as seen in this example:

[root@server.dawgland.com:~]# fdisk /dev/sdl

Welcome to fdisk (util-linux 2.35.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

The device contains 'exfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

Command (m for help):

To resolve this issue, the "wipe" options must be CORRECTLY used, as shown in this example:

[root@server.dawgland.com:~]# fdisk -W always /dev/sdl

Welcome to fdisk (util-linux 2.35.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

The device contains 'exfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

Command (m for help): w

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@server.dawgland.com:~]# sync
[root@server.dawgland.com:~]# sync
[root@server.dawgland.com:~]# fdisk /dev/sdl

Welcome to fdisk (util-linux 2.35.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xe345e7b0.

Command (m for help):q
[root@server.dawgland.com:~]#

As you can now see, the 'exfat' signature warning is not gone! The disk can now be safely and correctly partitioned as normal!

• • • The "wipe" switch has a caveat which requires the addition of "always" being used after the -W switch, which must be an upper-case W. Here is an example from a disk that had been partioned and formated using the "ExFAT" partition and filesystem, which held onto the 'exfat' signature and didn't want to clear it by a normal delete partion command and write partition table command. It still showed as 'exfat', as seen in these examples!

• df - DiskFree - Shows how much space is used by files, and how much space is left on storage devices connected to the system in one way or another, both locally mounted and remotely mounted file systems.
• du - DiskUsage - Shows how much space is used by files.
• ls - List - List files with a multitude of options and switches. I use ls -l, of which there usually exists an alias using "ll" as a shortcut to the "ls -l" command. The -l switch shows a Long listing, which means it shows not only file names, but file sizes and file attrubutes, ownerships, etc. I often add the "-a" switch to the "ls" command as well, meaning show "ALL" files, including "hidden" files, which start with a dot to hide them from a normal directory listing. So, I usually always use "ls -al" to list the contents of a directory, such as here:

[jamie@rocky9vm32.dawgland.com:~]$ ls -al
total 20
drwx------. 7 jamie jamie  170 Oct  5 02:01 .
drwxr-xr-x. 3 root  root    19 Jan 26  2023 ..
drwx------. 3 jamie jamie   17 Oct  4 23:04 .ansible
-rw-------. 1 jamie jamie 2875 Oct  5 02:10 .bash_history
-rw-r--r--. 1 jamie jamie   18 Nov  1  2022 .bash_logout
-rw-r--r--. 1 jamie jamie  141 Nov  1  2022 .bash_profile
-rw-r--r--. 1 jamie jamie  660 Jan 27  2023 .bashrc
drwx------. 3 jamie jamie   24 Jul 25 21:40 .cache
drwx------. 3 jamie jamie   17 Jul 25 21:38 .config
-rw-------. 1 jamie jamie   20 Oct  5 02:01 .lesshst
drwx------. 3 jamie jamie   19 Jul 25 21:38 .local
drwx------. 2 jamie jamie   61 Jan 27  2023 .ssh
[jamie@rocky9vm32.dawgland.com:~]$

MariaDB - The "Free" MySQL Alternative

MySQL, the long time "free" SQL server and client that used to be included in all standard Linux server installations server, has been acquired by Oracle, and they've "commercialized" it, so that it is no longer "officially" free for any commercial or business usage, and only "free" for personal not-for-profit use. This caused a bunch of long time developers to create what has become the "de-facto" MySQL replacement, and uses the exact same MySQL commands and syntax that we have become accustomed to throughout the years.

Installation of MariaDB

This is how I installed MariaDB on my new Fedora Linux 24, the latest and greatest! In one command, I've installed both the server and client, along with all of their dependencies! Here's how I did it:

[root@fc24 ~]# dnf install mariadb-server mariadb
Last metadata expiration check: 3:08:41 ago on Sun Sep 11 00:31:02 2016.
Dependencies resolved.
=============================================================================
 Package                Arch        Version               Repository    Size
=============================================================================
Installing:
 mariadb                x86_64      3:10.1.16-1.fc24      updates      6.3 M
 mariadb-common         x86_64      3:10.1.16-1.fc24      updates       66 k
 mariadb-config         x86_64      3:10.1.16-1.fc24      updates       29 k
 mariadb-errmsg         x86_64      3:10.1.16-1.fc24      updates      203 k
 mariadb-libs           x86_64      3:10.1.16-1.fc24      updates      654 k
 mariadb-server         x86_64      3:10.1.16-1.fc24      updates       19 M
 perl-DBD-MySQL         x86_64      4.036-1.fc24          updates      146 k
 perl-DBI               x86_64      1.634-3.fc24          fedora       729 k
 perl-Math-BigInt       noarch      1.9997.15-2.fc24      fedora       178 k
 perl-Math-Complex      noarch      1.59-362.fc24         updates       95 k
 perl-Storable          x86_64      1:2.53-348.fc24       updates       84 k

Transaction Summary
=============================================================================
Install  11 Packages

Total download size: 28 M
Installed size: 140 M
Is this ok [y/N]:y

Here is the rest of the output from the "dnf" after hitting the "Y" key to proceed to download the installation RPM packages, install them, and then clean things up to finish the installation:

Downloading Packages:
(1/11): mariadb-common-10.1.16-1.fc24.x86_64 158 kB/s |  66 kB     00:00    
(2/11): perl-DBI-1.634-3.fc24.x86_64.rpm     1.3 MB/s | 729 kB     00:00    
(3/11): perl-Math-BigInt-1.9997.15-2.fc24.no 1.9 MB/s | 178 kB     00:00    
(4/11): mariadb-errmsg-10.1.16-1.fc24.x86_64 361 kB/s | 203 kB     00:00    
(5/11): mariadb-config-10.1.16-1.fc24.x86_64 295 kB/s |  29 kB     00:00    
(6/11): perl-DBD-MySQL-4.036-1.fc24.x86_64.r 532 kB/s | 146 kB     00:00    
(7/11): mariadb-libs-10.1.16-1.fc24.x86_64.r 930 kB/s | 654 kB     00:00    
(8/11): perl-Math-Complex-1.59-362.fc24.noar 1.0 MB/s |  95 kB     00:00    
(9/11): perl-Storable-2.53-348.fc24.x86_64.r 1.0 MB/s |  84 kB     00:00    
(10/11): mariadb-10.1.16-1.fc24.x86_64.rpm   2.2 MB/s | 6.3 MB     00:02    
(11/11): mariadb-server-10.1.16-1.fc24.x86_6 3.8 MB/s |  19 MB     00:05    
-----------------------------------------------------------------------------
Total                                        4.3 MB/s |  28 MB     00:06     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Installing  : mariadb-config-3:10.1.16-1.fc24.x86_64                  1/11 
  Installing  : mariadb-common-3:10.1.16-1.fc24.x86_64                  2/11 
  Installing  : mariadb-errmsg-3:10.1.16-1.fc24.x86_64                  3/11 
  Installing  : mariadb-3:10.1.16-1.fc24.x86_64                         4/11 
  Installing  : mariadb-libs-3:10.1.16-1.fc24.x86_64                    5/11 
  Installing  : perl-Storable-1:2.53-348.fc24.x86_64                    6/11 
  Installing  : perl-Math-Complex-1.59-362.fc24.noarch                  7/11 
  Installing  : perl-Math-BigInt-1.9997.15-2.fc24.noarch                8/11 
  Installing  : perl-DBI-1.634-3.fc24.x86_64                            9/11 
  Installing  : perl-DBD-MySQL-4.036-1.fc24.x86_64                     10/11 
  Installing  : mariadb-server-3:10.1.16-1.fc24.x86_64                 11/11 
  Verifying   : mariadb-server-3:10.1.16-1.fc24.x86_64                  1/11 
  Verifying   : perl-DBI-1.634-3.fc24.x86_64                            2/11 
  Verifying   : mariadb-common-3:10.1.16-1.fc24.x86_64                  3/11 
  Verifying   : mariadb-errmsg-3:10.1.16-1.fc24.x86_64                  4/11 
  Verifying   : perl-Math-BigInt-1.9997.15-2.fc24.noarch                5/11 
  Verifying   : mariadb-3:10.1.16-1.fc24.x86_64                         6/11 
  Verifying   : mariadb-config-3:10.1.16-1.fc24.x86_64                  7/11 
  Verifying   : perl-DBD-MySQL-4.036-1.fc24.x86_64                      8/11 
  Verifying   : mariadb-libs-3:10.1.16-1.fc24.x86_64                    9/11 
  Verifying   : perl-Math-Complex-1.59-362.fc24.noarch                 10/11 
  Verifying   : perl-Storable-1:2.53-348.fc24.x86_64                   11/11 

Installed:
  mariadb.x86_64 3:10.1.16-1.fc24                                            
  mariadb-common.x86_64 3:10.1.16-1.fc24                                     
  mariadb-config.x86_64 3:10.1.16-1.fc24                                     
  mariadb-errmsg.x86_64 3:10.1.16-1.fc24                                     
  mariadb-libs.x86_64 3:10.1.16-1.fc24                                       
  mariadb-server.x86_64 3:10.1.16-1.fc24                                     
  perl-DBD-MySQL.x86_64 4.036-1.fc24                                         
  perl-DBI.x86_64 1.634-3.fc24                                               
  perl-Math-BigInt.noarch 1.9997.15-2.fc24                                   
  perl-Math-Complex.noarch 1.59-362.fc24                                     
  perl-Storable.x86_64 1:2.53-348.fc24                                       

Complete!
[root@fc24 ~]# 

Secure MariaDB Database Server Before Enabling SQL Server for Production

Before you enable the MariaDB SQL server, you MUST secure the server, either manually or using the included mysql_secure_installation shell script. Personally, I prefer to do it manually so that I can fine tune and tweak my installation. But the ultimate choice is your's.

Samba/CIFS Information --> Sharing Linux & Windows Stuff - A Necessary Evil~!

Excellent information on Samba 4 and using it to replace Windows AD, can be found here:
Setting up Samba 4 as Windows Active Directory Domain Controller

Password Info & Creation

Usually, passwords are created from the command line using the "passwd" command.
When creating a new user account, by default no password is set, so it must be done so manually!

If you need to create a pasword hash that can be copy and pasted into some other file manually,
there are a number of ways to do it, however I personally prefer a tool that is included with most
Linux distributions, aka "Distros". This tool is part of the Apache web server, so most systems already have it installed.
The htpasswd command is very versatile. This is an example of how to create a password hash manually:

[root@server ~]# htpasswd -c /tmp/tmppass tim
New password: 
Re-type new password: 
Adding password for user tim
[root@server ~]# cat /tmp/tmppass 
tim:$apr1$2/FJ6Trp$YF8RcdKJvkHKsyrZBQn9N0

The hash is after the "tim:" part, and can be copy and pasted into any file you need it for.

7zip Archive Handling With Linux

Depending on your distro, you will want to get either the 7za package for RPM and APT based distros, and the p7zip packages for Slackware, my preferred server distro!

Fedora VNC Information

This is where the symlink for the vncserver@ service resides

[jamie@server system]$ ls -l vncserver@.service 
-rw-r--r--. 1 root root 1734 Jan 21  2014 vncserver@.service
[jamie@server system]$ pwd
/lib/systemd/system

Puppy Linux

Puppy Linux is one of the tiniest Linux distributions, at only 335MB in size for the 32-bit version. The verified ISO for PuppyLinux Bionic32 can be downloaded from here: https://thebestlinux.com/pub/BionicPup32-19.03-231016.iso