diff --git a/coccinelle/empty-or-dash.cocci b/coccinelle/empty-or-dash.cocci
new file mode 100644
index 0000000000..bebaead2ff
--- /dev/null
+++ b/coccinelle/empty-or-dash.cocci
@@ -0,0 +1,5 @@
+@@
+expression s;
+@@
+- (isempty(s) || streq(s, "-"))
++ empty_or_dash(s)
diff --git a/src/basic/string-util.h b/src/basic/string-util.h
index 9cf11198b1..b23f4c8341 100644
--- a/src/basic/string-util.h
+++ b/src/basic/string-util.h
@@ -57,6 +57,16 @@ static inline const char *empty_to_dash(const char *str) {
         return isempty(str) ? "-" : str;
 }
 
+static inline bool empty_or_dash(const char *str) {
+        return !str ||
+                str[0] == 0 ||
+                (str[0] == '-' && str[1] == 0);
+}
+
+static inline const char *empty_or_dash_to_null(const char *p) {
+        return empty_or_dash(p) ? NULL : p;
+}
+
 static inline char *startswith(const char *s, const char *prefix) {
         size_t l;
 
diff --git a/src/import/export.c b/src/import/export.c
index 4566a66a15..77d24b8635 100644
--- a/src/import/export.c
+++ b/src/import/export.c
@@ -78,8 +78,7 @@ static int export_tar(int argc, char *argv[], void *userdata) {
 
         if (argc >= 3)
                 path = argv[2];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         determine_compression_from_filename(path);
 
@@ -155,8 +154,7 @@ static int export_raw(int argc, char *argv[], void *userdata) {
 
         if (argc >= 3)
                 path = argv[2];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         determine_compression_from_filename(path);
 
diff --git a/src/import/import-fs.c b/src/import/import-fs.c
index 974c0f5536..04344492c8 100644
--- a/src/import/import-fs.c
+++ b/src/import/import-fs.c
@@ -117,15 +117,13 @@ static int import_fs(int argc, char *argv[], void *userdata) {
 
         if (argc >= 2)
                 path = argv[1];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         if (argc >= 3)
                 local = argv[2];
         else if (path)
                 local = basename(path);
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 if (!machine_name_is_valid(local)) {
diff --git a/src/import/import.c b/src/import/import.c
index e3a1ae8a8b..cc28557459 100644
--- a/src/import/import.c
+++ b/src/import/import.c
@@ -49,15 +49,13 @@ static int import_tar(int argc, char *argv[], void *userdata) {
 
         if (argc >= 2)
                 path = argv[1];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         if (argc >= 3)
                 local = argv[2];
         else if (path)
                 local = basename(path);
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = tar_strip_suffixes(local, &ll);
@@ -145,15 +143,13 @@ static int import_raw(int argc, char *argv[], void *userdata) {
 
         if (argc >= 2)
                 path = argv[1];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         if (argc >= 3)
                 local = argv[2];
         else if (path)
                 local = basename(path);
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = raw_strip_suffixes(local, &ll);
diff --git a/src/import/pull.c b/src/import/pull.c
index 68b1221b72..7e8712493f 100644
--- a/src/import/pull.c
+++ b/src/import/pull.c
@@ -64,8 +64,7 @@ static int pull_tar(int argc, char *argv[], void *userdata) {
                 local = l;
         }
 
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = tar_strip_suffixes(local, &ll);
@@ -151,8 +150,7 @@ static int pull_raw(int argc, char *argv[], void *userdata) {
                 local = l;
         }
 
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = raw_strip_suffixes(local, &ll);
diff --git a/src/locale/keymap-util.c b/src/locale/keymap-util.c
index 17540089ba..b8bd181c16 100644
--- a/src/locale/keymap-util.c
+++ b/src/locale/keymap-util.c
@@ -32,10 +32,6 @@ static bool startswith_comma(const char *s, const char *prefix) {
         return IN_SET(*s, ',', '\0');
 }
 
-static const char* strnulldash(const char *s) {
-        return isempty(s) || streq(s, "-") ? NULL : s;
-}
-
 static const char* systemd_kbd_model_map(void) {
         const char* s;
 
@@ -551,15 +547,15 @@ int vconsole_convert_to_x11(Context *c) {
                         if (!streq(c->vc_keymap, a[0]))
                                 continue;
 
-                        if (!streq_ptr(c->x11_layout, strnulldash(a[1])) ||
-                            !streq_ptr(c->x11_model, strnulldash(a[2])) ||
-                            !streq_ptr(c->x11_variant, strnulldash(a[3])) ||
-                            !streq_ptr(c->x11_options, strnulldash(a[4]))) {
+                        if (!streq_ptr(c->x11_layout, empty_or_dash_to_null(a[1])) ||
+                            !streq_ptr(c->x11_model, empty_or_dash_to_null(a[2])) ||
+                            !streq_ptr(c->x11_variant, empty_or_dash_to_null(a[3])) ||
+                            !streq_ptr(c->x11_options, empty_or_dash_to_null(a[4]))) {
 
-                                if (free_and_strdup(&c->x11_layout, strnulldash(a[1])) < 0 ||
-                                    free_and_strdup(&c->x11_model, strnulldash(a[2])) < 0 ||
-                                    free_and_strdup(&c->x11_variant, strnulldash(a[3])) < 0 ||
-                                    free_and_strdup(&c->x11_options, strnulldash(a[4])) < 0)
+                                if (free_and_strdup(&c->x11_layout, empty_or_dash_to_null(a[1])) < 0 ||
+                                    free_and_strdup(&c->x11_model, empty_or_dash_to_null(a[2])) < 0 ||
+                                    free_and_strdup(&c->x11_variant, empty_or_dash_to_null(a[3])) < 0 ||
+                                    free_and_strdup(&c->x11_options, empty_or_dash_to_null(a[4])) < 0)
                                         return -ENOMEM;
 
                                 modified = true;
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index c8607bcec3..d98027a0ca 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -1993,16 +1993,6 @@ static int transfer_image_common(sd_bus *bus, sd_bus_message *m) {
         return -r;
 }
 
-static const char *nullify_dash(const char *p) {
-        if (isempty(p))
-                return NULL;
-
-        if (streq(p, "-"))
-                return NULL;
-
-        return p;
-}
-
 static int import_tar(int argc, char *argv[], void *userdata) {
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
         _cleanup_free_ char *ll = NULL, *fn = NULL;
@@ -2014,10 +2004,10 @@ static int import_tar(int argc, char *argv[], void *userdata) {
         assert(bus);
 
         if (argc >= 2)
-                path = nullify_dash(argv[1]);
+                path = empty_or_dash_to_null(argv[1]);
 
         if (argc >= 3)
-                local = nullify_dash(argv[2]);
+                local = empty_or_dash_to_null(argv[2]);
         else if (path) {
                 r = path_extract_filename(path, &fn);
                 if (r < 0)
@@ -2081,10 +2071,10 @@ static int import_raw(int argc, char *argv[], void *userdata) {
         assert(bus);
 
         if (argc >= 2)
-                path = nullify_dash(argv[1]);
+                path = empty_or_dash_to_null(argv[1]);
 
         if (argc >= 3)
-                local = nullify_dash(argv[2]);
+                local = empty_or_dash_to_null(argv[2]);
         else if (path) {
                 r = path_extract_filename(path, &fn);
                 if (r < 0)
@@ -2148,10 +2138,10 @@ static int import_fs(int argc, char *argv[], void *userdata) {
         assert(bus);
 
         if (argc >= 2)
-                path = nullify_dash(argv[1]);
+                path = empty_or_dash_to_null(argv[1]);
 
         if (argc >= 3)
-                local = nullify_dash(argv[2]);
+                local = empty_or_dash_to_null(argv[2]);
         else if (path) {
                 r = path_extract_filename(path, &fn);
                 if (r < 0)
@@ -2230,8 +2220,7 @@ static int export_tar(int argc, char *argv[], void *userdata) {
 
         if (argc >= 3)
                 path = argv[2];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         if (path) {
                 determine_compression_from_filename(path);
@@ -2280,8 +2269,7 @@ static int export_raw(int argc, char *argv[], void *userdata) {
 
         if (argc >= 3)
                 path = argv[2];
-        if (isempty(path) || streq(path, "-"))
-                path = NULL;
+        path = empty_or_dash_to_null(path);
 
         if (path) {
                 determine_compression_from_filename(path);
@@ -2338,8 +2326,7 @@ static int pull_tar(int argc, char *argv[], void *userdata) {
                 local = l;
         }
 
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = tar_strip_suffixes(local, &ll);
@@ -2402,8 +2389,7 @@ static int pull_raw(int argc, char *argv[], void *userdata) {
                 local = l;
         }
 
-        if (isempty(local) || streq(local, "-"))
-                local = NULL;
+        local = empty_or_dash_to_null(local);
 
         if (local) {
                 r = raw_strip_suffixes(local, &ll);
diff --git a/src/sysusers/sysusers.c b/src/sysusers/sysusers.c
index 9a85a20be3..843c3837d1 100644
--- a/src/sysusers/sysusers.c
+++ b/src/sysusers/sysusers.c
@@ -1411,7 +1411,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
                                        "[%s:%u] Unknown command type '%c'.", fname, line, action[0]);
 
         /* Verify name */
-        if (isempty(name) || streq(name, "-"))
+        if (empty_or_dash(name))
                 name = mfree(name);
 
         if (name) {
@@ -1426,7 +1426,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         }
 
         /* Verify id */
-        if (isempty(id) || streq(id, "-"))
+        if (empty_or_dash(id))
                 id = mfree(id);
 
         if (id) {
@@ -1437,7 +1437,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         }
 
         /* Verify description */
-        if (isempty(description) || streq(description, "-"))
+        if (empty_or_dash(description))
                 description = mfree(description);
 
         if (description) {
@@ -1453,7 +1453,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         }
 
         /* Verify home */
-        if (isempty(home) || streq(home, "-"))
+        if (empty_or_dash(home))
                 home = mfree(home);
 
         if (home) {
@@ -1469,7 +1469,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         }
 
         /* Verify shell */
-        if (isempty(shell) || streq(shell, "-"))
+        if (empty_or_dash(shell))
                 shell = mfree(shell);
 
         if (shell) {
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 84e104f9b5..d9d1cc1c1a 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -2507,7 +2507,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer, bool
                 return -EIO;
         }
 
-        if (!isempty(buffer) && !streq(buffer, "-")) {
+        if (!empty_or_dash(buffer)) {
                 i.argument = strdup(buffer);
                 if (!i.argument)
                         return log_oom();
@@ -2704,7 +2704,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer, bool
                 free_and_replace(i.path, p);
         }
 
-        if (!isempty(user) && !streq(user, "-")) {
+        if (!empty_or_dash(user)) {
                 const char *u = user;
 
                 r = get_user_creds(&u, &i.uid, NULL, NULL, NULL, USER_CREDS_ALLOW_MISSING);
@@ -2716,7 +2716,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer, bool
                 i.uid_set = true;
         }
 
-        if (!isempty(group) && !streq(group, "-")) {
+        if (!empty_or_dash(group)) {
                 const char *g = group;
 
                 r = get_group_creds(&g, &i.gid, USER_CREDS_ALLOW_MISSING);
@@ -2729,7 +2729,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer, bool
                 i.gid_set = true;
         }
 
-        if (!isempty(mode) && !streq(mode, "-")) {
+        if (!empty_or_dash(mode)) {
                 const char *mm = mode;
                 unsigned m;
 
@@ -2749,7 +2749,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer, bool
         } else
                 i.mode = IN_SET(i.type, CREATE_DIRECTORY, TRUNCATE_DIRECTORY, CREATE_SUBVOLUME, CREATE_SUBVOLUME_INHERIT_QUOTA, CREATE_SUBVOLUME_NEW_QUOTA) ? 0755 : 0644;
 
-        if (!isempty(age) && !streq(age, "-")) {
+        if (!empty_or_dash(age)) {
                 const char *a = age;
 
                 if (*a == '~') {