hostnamectl: say that tags can be removed by glob

man/hostnamectl.xml

@@ -180,12 +180,15 @@
         <para>Alternatively, each argument may be prefixed with <literal>+</literal> or <literal>-</literal>
         to incrementally update the configured tags rather than replacing them: an argument prefixed with
         <literal>+</literal> adds all of its (colon-separated) tags to the list, one prefixed with
-        <literal>-</literal> removes them. For example, <command>hostnamectl tags +foo:bar -quux:ooo</command>
-        adds the tags <literal>foo</literal> and <literal>bar</literal> and removes <literal>quux</literal>
-        and <literal>ooo</literal>. The prefix applies to the whole argument, i.e. to every tag listed within
-        it. Adding a <literal><replaceable>key</replaceable>=<replaceable>value</replaceable></literal> tag
-        replaces any value previously assigned to the same key. Prefixed and unprefixed arguments may not be
-        combined in a single invocation.</para>
+        <literal>-</literal> specifies a removal pattern. For example, <command>hostnamectl tags +foo:bar
+        -quux:ooo=*</command> adds the tags <literal>foo</literal> and <literal>bar</literal> and removes
+        <literal>quux</literal> and any assignment of <literal>ooo=</literal>. The prefix applies to the
+        whole argument, i.e. to every tag listed within it. Adding a
+        <literal><replaceable>key</replaceable>=<replaceable>value</replaceable></literal> tag replaces any
+        value previously assigned to the same key. Prefixed and unprefixed arguments may not be combined in a
+        single invocation. Removal patterns may use shell-style globbing to remove any matching tags,
+        <citerefentry project='man-pages'><refentrytitle>glob</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+        </para>
 
         <para>If <option>--apply</option> is specified, no <replaceable>TAG</replaceable> arguments may be
         given. Instead, <filename>systemd-hostnamed</filename> is asked to apply the tag configuration

test/units/TEST-71-HOSTNAME.sh

@@ -474,7 +474,20 @@ testcase_tags() {
     hostnamectl tags +foo=b
     assert_eq "$(hostnamectl tags)" "foo:foo=b"
     grep -x "TAGS=foo:foo=b" /etc/machine-info >/dev/null
-    hostnamectl tags alpha:beta:quux
+
+    # A '*' suffix on a tag to remove removes all tags with that prefix, before tags are added.
+    hostnamectl tags company.x:company.bar=old:companyfoo:other
+    hostnamectl tags -- '-company.*' +company.foo:company.bar=waldo
+    assert_eq "$(hostnamectl tags)" "company.bar=waldo:company.foo:companyfoo:other"
+    hostnamectl tags -- '-company.*:other' -companyfoo +new
+    assert_eq "$(hostnamectl tags)" "new"
+    hostnamectl tags new:k=1:kx=2:kk:k
+    hostnamectl tags -- '-k=*'
+    assert_eq "$(hostnamectl tags)" "k:kk:kx=2:new"
+    # The '*' suffix is only allowed for removal
+    (! hostnamectl tags -- '+foo*')
+    (! hostnamectl tags -- 'foo*')
+    assert_eq "$(hostnamectl tags)" "k:kk:kx=2:new"
 
     # Plain and prefixed arguments may not be mixed.
     (! hostnamectl tags foo +bar)