shell-completion/zsh: silence error when machinectl is not installed

This fixes a few unrelated issues:
- when ENABLE_MACHINED is false, machinectl is not installed, but _sd_machines
  is still used in a few places that want to complete -M and such.
  Also, bash completion calls machinectl in various places.
  Make missing machinectl mean "no machines" in this case, so
  that no error is generated in the callers.
- machinectl list --full would print multiple lines of output per machine,
  breaking grep, issue introduced in e2268fa437.
  Using --max-addresses=1 would fix the issue, but let's use
  --max-addresses=0 because we now can.
- the lists used in various places were slightly different for no good reason.
- don't use a subshell if not necessary.

The code for bash still uses the same combined list of images and running
machines for various commands. The zsh code uses images for start/clone, and
running machines for the rest. Maybe something to fix in the future.

Replaces #25048.

shell-completion/bash/busctl

@@ -25,8 +25,9 @@ __contains_word () {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager 2>/dev/null |
-        { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __get_busnames() {

shell-completion/bash/journalctl

@@ -27,8 +27,9 @@ __contains_word () {
 
 __get_machines() {
     local a b
-    (machinectl list-images --full --no-legend --no-pager; machinectl list --full --no-legend --no-pager; echo ".host") | \
-        { while read a b; do echo " $a"; done; } | sort -u;
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __syslog_priorities=(emerg alert crit err warning notice info debug)

shell-completion/bash/loginctl

@@ -31,8 +31,9 @@ __get_all_seats    () { loginctl --no-legend list-seats    | { while read -r a b
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager 2>/dev/null |
-        { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _loginctl () {

shell-completion/bash/machinectl

@@ -25,8 +25,9 @@ __contains_word() {
 
 __get_machines() {
     local a b
-    (machinectl list-images --full --no-legend --no-pager; machinectl list --full --no-legend --no-pager; echo ".host") | \
-	{ while read a b; do echo " $a"; done; } | sort -u;
+    { machinectl list-images --full --no-legend --no-pager 2>/dev/null; machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _machinectl() {

shell-completion/bash/portablectl

@@ -25,8 +25,9 @@ __contains_word () {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager 2>/dev/null |
-        { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _portablectl() {

shell-completion/bash/systemctl.in

@@ -115,8 +115,9 @@ __get_all_unit_files () { { __systemctl $1 list-unit-files "$2*"; } | { while re
 
 __get_machines() {
     local a b
-    { machinectl list-images --full --no-legend --no-pager; machinectl list --full --no-legend --no-pager; } | \
-        { while read a b; do echo " $a"; done; }
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _systemctl () {

shell-completion/bash/systemd-analyze

@@ -27,7 +27,9 @@ __contains_word () {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __get_units_all() {

shell-completion/bash/systemd-cgls

@@ -25,7 +25,9 @@ __contains_word() {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __get_units_have_cgroup() {

shell-completion/bash/systemd-cgtop

@@ -25,7 +25,9 @@ __contains_word() {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _systemd_cgtop() {

shell-completion/bash/systemd-nspawn

@@ -35,7 +35,9 @@ __get_slices() {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __get_env() {

shell-completion/bash/systemd-run

@@ -26,7 +26,9 @@ __get_slice_units () { __systemctl $1 list-units --all -t slice \
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 _systemd_run() {

shell-completion/bash/timedatectl

@@ -27,7 +27,9 @@ __contains_word () {
 
 __get_machines() {
     local a b
-    machinectl list --full --no-legend --no-pager | { while read a b; do echo " $a"; done; };
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo " $a"; done; } | \
+        sort -u
 }
 
 __get_interfaces(){

shell-completion/zsh/_sd_machines

@@ -3,7 +3,10 @@
 
 (( $+functions[__sd_machines_get_machines] )) ||
     __sd_machines_get_machines () {
-        machinectl --full --no-legend --no-pager list |  {while read -r a b; do echo $a; done;};
+
+    { machinectl list --full --max-addresses=0 --no-legend --no-pager 2>/dev/null; echo ".host"; } | \
+	{ while read a b; do echo "$a"; done; } | \
+        sort -u
     }
 
 local -a _machines