check_http first lines

docs/20_Checks/check_systemdunit.md

@@ -16,7 +16,7 @@ A unit is everything listed by systemctl command - services, timers, targets, ..
 ______________________________________________________________________
 
 CHECK_SYSTEMDUNIT
-v1.0
+v1.1
 
 (c) Institute for Medical Education - University of Bern
 Licence: GNU GPL 3
@@ -30,21 +30,53 @@ The status is unknown if the command systemctl is not found.
 The status is critical if the service does not exist or is not running.
 
 SYNTAX:
-  check_systemdunit [-h] UNIT
+  check_systemdunit [-h|-l|-s] UNIT
 
 OPTIONS:
+
   -h     this help
+  -l     list all units
+  -s     list service units
+
   UNIT   Name of a unit - see output of 'systemctl' 
 
 EXAMPLES:
 
-  check_systemdunit mysql.service
-         show status of service mysql
+  check_systemdunit -s
+         list all existing services. For a unit check you need to add the name
+         in the 1st column.
+
+  check_systemdunit nginx.service
+         show status of nginx webservice
 
 ```
 
 ## Examples
 
+### List services
+
+You maybe want to start to get a list of services to pick an existing one that you wanna check periodically.
+
+You can use ``systemctl --no-legend --no-pager --type service`` or ``$ ./check_systemdunit -s``
+
+```txt
+List of service units:
+
+  alsa-restore.service                                  loaded active exited  Save/Restore Sound Card State
+  apparmor.service                                      loaded active exited  Load AppArmor profiles
+  avahi-daemon.service                                  loaded active running Avahi mDNS/DNS-SD Stack
+  bluetooth.service                                     loaded active running Bluetooth service
+  clamav-daemon.service                                 loaded active running Clam AntiVirus userspace daemon
+  clamav-freshclam.service                              loaded active running ClamAV virus database updater
+  colord.service                                        loaded active running Manage, Install and Generate Color Profiles
+  cronie.service                                        loaded active running Periodic Command Scheduler
+  ...
+```
+
+### Check a service
+
+To check a single service you need to add the unit name in the 1st column.
+
 ``$ ./check_systemdunit nginx`` returns
 
 ```txt
@@ -67,3 +99,7 @@ If a service does not exist: ``./check_systemdunit justadummy`` returns
 ```txt
 CRITICAL: Unit justadummy.service could not be found.
 ```
+
+### Other units
+
+With ``$ ./check_systemdunit -l`` you get a grouped list of all unit types. check_systemdunit handles all types - not only services.