System

View system resources (CPU, memory, disk, etc).

View and manage processes and kill those using excessive resources.

Resources

top displays all running processes in the system and their resource consumption (cpu, memory)

top -p PID for a specific process.

htop displays and manages processes in the operating server, –-tree shows process hierarchical view.

Processes

ps summarizes the status of all running processes in your Linux system at a specific time

ps ru shows only running processes for the current user

time measures the execution time of commands or scripts to gain insights into system performance.

time command-or-script && another-command-or-sript

jobs -l show tasks or commands running in the current shell (useful if you forget about background jobs)

Use the kill command to terminate a process using its ID. Here’s the basic syntax:

kill -9 Process_ID to kill a specific process (using the ID shown via the ps command)

killall process-name e.g. killall chrome

To obtain the process ID, run the following command:

ps ux

The kill command uses SIGTERM to allow a process a little time to save data and release resources gracefully before exiting.

Kernel

uname (unix name) displays detailed information about your Linux machine, including hardware, name, and operating system kernel.

❯ uname -a
Linux gkar 6.12.32-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.32-1 (2025-06-07) x86_64 GNU/Linux

Flags:

-a --all print all information, in the following order, except omit -p and -i if unknown: -s --kernel-name print the kernel name -n --nodename print the network node hostname -r --kernel-release print the kernel release -v --kernel-version print the kernel version -m --machine print the machine hardware name -p --processor print the processor type (non-portable) -i --hardware-platform print the hardware platform (non-portable) -o --operating-system print the operating system

Network

• hostname - show or set the system's host name
• domainname - show or set the system's NIS/YP domain name
• ypdomainname - show or set the system's NIS/YP domain name
• nisdomainname - show or set the system's NIS/YP domain name
• dnsdomainname - show the system's DNS domain name

ip address shows the Network IP addresses available on the operating system

Services

systemctl to list and manage services in the system

systemctl subcommand [service_name][options]

The subcommands represent your task, like listing, restarting, terminating, or enabling the services. For example, we will list Linux services using this:

sudo systemctl list-unit-files --type service --all

systemctl show lists all services

System Control - all information

❯ systemctl show
Version=257.6-1
Features=+PAM +AUDIT +SELINUX +APPARMOR +IMA +IPE +SMACK +SECCOMP +GCRYPT -GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBCR>
Architecture=x86-64
Tainted=unmerged-bin
FirmwareTimestampMonotonic=17770382
LoaderTimestampMonotonic=7539019
KernelTimestamp=Thu 2025-07-03 08:57:35 BST
KernelTimestampMonotonic=0
InitRDTimestampMonotonic=0
UserspaceTimestamp=Thu 2025-07-03 08:57:41 BST
UserspaceTimestampMonotonic=5422672
FinishTimestamp=Thu 2025-07-03 08:57:54 BST
FinishTimestampMonotonic=18590863
ShutdownStartTimestampMonotonic=0
SecurityStartTimestamp=Thu 2025-07-03 08:57:41 BST
SecurityStartTimestampMonotonic=5429873
SecurityFinishTimestamp=Thu 2025-07-03 08:57:41 BST
SecurityFinishTimestampMonotonic=5431546
GeneratorsStartTimestamp=Thu 2025-07-03 08:57:41 BST
GeneratorsStartTimestampMonotonic=5704612
GeneratorsFinishTimestamp=Thu 2025-07-03 08:57:41 BST
GeneratorsFinishTimestampMonotonic=5747292
UnitsLoadStartTimestamp=Thu 2025-07-03 08:57:41 BST
UnitsLoadStartTimestampMonotonic=5747313
UnitsLoadFinishTimestamp=Thu 2025-07-03 08:57:41 BST
UnitsLoadFinishTimestampMonotonic=5856839
UnitsLoadTimestamp=Thu 2025-07-03 09:23:28 BST
UnitsLoadTimestampMonotonic=1412993331
InitRDSecurityStartTimestampMonotonic=0
InitRDSecurityFinishTimestampMonotonic=0
InitRDGeneratorsStartTimestampMonotonic=0
InitRDGeneratorsFinishTimestampMonotonic=0
InitRDUnitsLoadStartTimestampMonotonic=0
InitRDUnitsLoadFinishTimestampMonotonic=0
LogLevel=info
LogTarget=journal-or-kmsg
NNames=427
NFailedUnits=1
NJobs=0
NInstalledJobs=349
NFailedJobs=1
Progress=1
Environment=LANG=en_GB.UTF-8 LANGUAGE=en_GB:en PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
ConfirmSpawn=no
ShowStatus=no
UnitPath=/etc/systemd/system.control /run/systemd/system.control /run/systemd/transient /run/systemd/generator.early /etc/systemd/system /etc/systemd/system.attached /run>
DefaultStandardOutput=journal
DefaultStandardError=inherit
WatchdogLastPingTimestampMonotonic=18446744073709551615
RuntimeWatchdogUSec=0
RuntimeWatchdogPreUSec=0
RebootWatchdogUSec=10min
KExecWatchdogUSec=0
ServiceWatchdogs=yes
SystemState=degraded
DefaultTimerAccuracyUSec=1min
DefaultTimeoutStartUSec=1min 30s
DefaultTimeoutStopUSec=1min 30s
DefaultTimeoutAbortUSec=1min 30s
DefaultDeviceTimeoutUSec=1min 30s
DefaultRestartUSec=100ms
DefaultStartLimitIntervalUSec=10s
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View logs

watch run a utility every 2 seconds (or given interval) to monitor changes in the output.

-n to specify the delay in seconds.

-d highlights changes in the output.

Shutdown and reboot

shutdown to turn off or restart your Linux system at a specific time, shutdown [option] [time] [message]. The message is shown to all users logged into the system.

-r to reboot the system.

shutdown -r now