The sudo systemctl status command will show a tree view of all running processes on your Linux machine. This is quite comprehensive and very useful output.
Here is a sample.
4.4 Mon Mar 04 jason@Yog-Sothoth 1: $ sudo systemctl status ● Yog-Sothoth State: running Jobs: 0 queued Failed: 0 units Since: Mon 2019-03-04 18:52:58 AEDT; 10h left CGroup: / ├─user.slice │ ├─user-123.slice │ │ ├─session-c4.scope │ │ │ ├─2467 gdm-session-worker [pam/gdm-launch-environment] │ │ │ ├─2520 /usr/lib/gdm3/gdm-x-session gnome-session --autostart /usr/share/gdm/greeter/autostart │ │ │ ├─2522 /usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/123/gdm/Xauthority -background none -noreset -keeptty -verbose 3 │ │ │ ├─2541 /usr/lib/gnome-session/gnome-session-binary --autostart /usr/share/gdm/greeter/autostart │ │ │ ├─2560 /usr/bin/gnome-shell │ │ │ ├─3120 ibus-daemon --xim --panel disable │ │ │ ├─3133 /usr/lib/ibus/ibus-dconf │ │ │ ├─3135 /usr/lib/ibus/ibus-x11 --kill-daemon │ │ │ ├─3407 /usr/lib/gnome-settings-daemon/gsd-xsettings │ │ │ ├─3410 /usr/lib/gnome-settings-daemon/gsd-a11y-settings │ │ │ ├─3411 /usr/lib/gnome-settings-daemon/gsd-clipboard │ │ │ ├─3419 /usr/lib/gnome-settings-daemon/gsd-color │ │ │ ├─3422 /usr/lib/gnome-settings-daemon/gsd-datetime │ │ │ ├─3427 /usr/lib/gnome-settings-daemon/gsd-housekeeping │ │ │ ├─3435 /usr/lib/gnome-settings-daemon/gsd-keyboard │ │ │ ├─3439 /usr/lib/gnome-settings-daemon/gsd-media-keys │ │ │ ├─3445 /usr/lib/gnome-settings-daemon/gsd-mouse │ │ │ ├─3446 /usr/lib/gnome-settings-daemon/gsd-power │ │ │ ├─3451 /usr/lib/gnome-settings-daemon/gsd-print-notifications │ │ │ ├─3457 /usr/lib/gnome-settings-daemon/gsd-rfkill │ │ │ ├─3462 /usr/lib/gnome-settings-daemon/gsd-screensaver-proxy │ │ │ ├─3465 /usr/lib/gnome-settings-daemon/gsd-sharing │ │ │ ├─3468 /usr/lib/gnome-settings-daemon/gsd-smartcard │ │ │ ├─3473 /usr/lib/gnome-settings-daemon/gsd-sound │ │ │ ├─3476 /usr/lib/gnome-settings-daemon/gsd-wacom │ │ │ └─3502 /usr/lib/ibus/ibus-engine-simple │ │ └─user@123.service │ │ ├─xdg-permission-store.service │ │ │ └─3364 /usr/lib/xdg-desktop-portal/xdg-permission-store │ │ ├─pulseaudio.service │ │ │ └─2593 /usr/bin/pulseaudio --daemonize=no │ │ ├─init.scope │ │ │ ├─2508 /lib/systemd/systemd --user │ │ │ └─2509 (sd-pam) │ │ ├─at-spi-dbus-bus.service │ │ │ ├─2543 /usr/lib/at-spi2-core/at-spi-bus-launcher │ │ │ ├─2548 /usr/bin/dbus-daemon --config-file=/usr/share/defaults/at-spi2/accessibility.conf --nofork --print-address 3 │ │ │ └─2551 /usr/lib/at-spi2-core/at-spi2-registryd --use-gnome-session │ │ └─dbus.service │ │ ├─2534 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only │ │ └─3139 /usr/lib/ibus/ibus-portal │ └─user-1000.slice │ ├─user@1000.service │ │ ├─gvfs-goa-volume-monitor.service |
To get information about just one process, use this command.
4.4 Mon Mar 04 jason@Yog-Sothoth 1: $ sudo systemctl status mysql.service ● mysql.service - MySQL Community Server Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2019-03-04 07:51:59 AEDT; 58min ago Process: 1763 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid (code=exited, status=0/SUCCESS) Process: 1671 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS) Main PID: 1765 (mysqld) Tasks: 28 (limit: 4915) CGroup: /system.slice/mysql.service └─1765 /usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid Mar 04 07:53:50 Yog-Sothoth systemd[1]: Starting MySQL Community Server... Mar 04 07:51:59 Yog-Sothoth systemd[1]: Started MySQL Community Server. |
This can also show messages pertaining to the service, as well as all instances that are running and their PID.
4.4 Mon Mar 04 jason@Yog-Sothoth 1: $ sudo systemctl status apache2.service ● apache2.service - The Apache HTTP Server Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled) Drop-In: /lib/systemd/system/apache2.service.d └─apache2-systemd.conf Active: active (running) since Mon 2019-03-04 07:53:55 AEDT; 57min ago Process: 6790 ExecReload=/usr/sbin/apachectl graceful (code=exited, status=0/SUCCESS) Process: 1672 ExecStart=/usr/sbin/apachectl start (code=exited, status=0/SUCCESS) Main PID: 1749 (apache2) Tasks: 6 (limit: 4915) CGroup: /system.slice/apache2.service ├─1749 /usr/sbin/apache2 -k start ├─6794 /usr/sbin/apache2 -k start ├─6795 /usr/sbin/apache2 -k start ├─6796 /usr/sbin/apache2 -k start ├─6797 /usr/sbin/apache2 -k start └─6798 /usr/sbin/apache2 -k start Mar 04 07:53:50 Yog-Sothoth systemd[1]: Starting The Apache HTTP Server... Mar 04 07:53:54 Yog-Sothoth apachectl[1672]: AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppre Mar 04 07:53:55 Yog-Sothoth systemd[1]: Started The Apache HTTP Server. Mar 04 07:56:44 Yog-Sothoth systemd[1]: Reloading The Apache HTTP Server. Mar 04 07:56:44 Yog-Sothoth apachectl[6790]: AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppre Mar 04 07:56:44 Yog-Sothoth systemd[1]: Reloaded The Apache HTTP Server. |
Another good reason to run Systemd on your Linux machine. This makes retrieving information about a running service even easier than before.
Use this command to show the properties of a running service.
4.4 Mon Mar 04 jason@Yog-Sothoth 1: $ sudo systemctl show mysql.service |
This is a part of the output, this shows everything you could possibly want.
Type=forking Restart=on-failure PIDFile=/run/mysqld/mysqld.pid NotifyAccess=none RestartUSec=100ms TimeoutStartUSec=10min TimeoutStopUSec=10min RuntimeMaxUSec=infinity WatchdogUSec=0 WatchdogTimestamp=Mon 2019-03-04 07:51:59 AEDT WatchdogTimestampMonotonic=110219190 PermissionsStartOnly=yes RootDirectoryStartOnly=no RemainAfterExit=no GuessMainPID=yes MainPID=1765 ControlPID=0 FileDescriptorStoreMax=0 NFileDescriptorStore=0 StatusErrno=0 Result=success |