systemd-analyze: added the verb unit-shell to spawn and attach shell

shell-completion/bash/systemd-analyze

@@ -82,6 +82,7 @@ _systemd_analyze() {
         [FDSTORE]='fdstore'
         [CAPABILITY]='capability'
         [TRANSIENT_SETTINGS]='transient-settings'
+        [UNIT_SHELL]='unit-shell'
     )
 
     local CONFIGS='locale.conf systemd/bootchart.conf systemd/coredump.conf systemd/journald.conf
@@ -233,6 +234,13 @@ _systemd_analyze() {
         else
             comps="$(systemctl --no-legend --no-pager -t help)"
         fi
+
+    elif __contains_word "$verb" ${VERBS[UNIT_SHELL]}; then
+        if [[ $cur = -* ]]; then
+            comps='--help --version'
+        else
+            comps=$( __get_services $mode )
+        fi
     fi
 
     COMPREPLY=( $(compgen -W '$comps' -- "$cur") )