bash-completion: add completions for hostnamectl

bash-completion/systemd-bash-completion.sh

@@ -439,3 +439,38 @@ _localectl() {
         return 0
 }
 complete -F _localectl localectl
+
+_hostnamectl() {
+        local verb comps
+        local cur=${COMP_WORDS[COMP_CWORD]} prev=${COMP_WORDS[COMP_CWORD-1]}
+        local OPTS='-h --help --version --transient --static --pretty
+                    --no-ask-password -H --host'
+
+        if [[ $cur = -* ]]; then
+                COMPREPLY=( $(compgen -W '${OPTS[*]}' -- "$cur") )
+                return 0
+        fi
+
+        local -A VERBS=(
+                [STANDALONE]='status'
+                     [ICONS]='set-icon-name'
+                      [NAME]='set-hostname'
+        )
+
+        for ((i=0; i <= COMP_CWORD; i++)); do
+                if __contains_word "${COMP_WORDS[i]}" ${VERBS[*]}; then
+                        verb=${COMP_WORDS[i]}
+                        break
+                fi
+        done
+
+        if [[ -z $verb ]]; then
+                comps=${VERBS[*]}
+        elif __contains_word "$verb" ${VERBS[STANDALONE]} ${VERBS[ICONS]} ${VERBS[NAME]}; then
+                comps=''
+        fi
+
+        COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
+        return 0
+}
+complete -F _hostnamectl hostnamectl