diff --git a/common/common.cpp b/common/common.cpp
index 804af1d94..0bf01ce2a 100644
--- a/common/common.cpp
+++ b/common/common.cpp
@@ -373,7 +373,7 @@ bool gpt_params_parse_ex(int argc, char ** argv, gpt_params & params, std::vecto
                 }
             } catch (std::exception & e) {
                 throw std::invalid_argument(format(
-                    "error while handling environment variable \"%s\": %s\n\n", opt.env.c_str(), e.what()));
+                    "error while handling environment variable \"%s\": %s\n\n", opt.env, e.what()));
             }
         }
     }
@@ -395,7 +395,7 @@ bool gpt_params_parse_ex(int argc, char ** argv, gpt_params & params, std::vecto
         }
         auto opt = *arg_to_options[arg];
         if (opt.has_value_from_env()) {
-            fprintf(stderr, "warn: %s environment variable is set, but will be overwritten by command line argument %s\n", opt.env.c_str(), arg.c_str());
+            fprintf(stderr, "warn: %s environment variable is set, but will be overwritten by command line argument %s\n", opt.env, arg.c_str());
         }
         try {
             if (opt.handler_void) {
@@ -595,15 +595,19 @@ std::string llama_arg::to_string() {
     std::string leading_spaces(n_leading_spaces, ' ');
 
     std::ostringstream ss;
-    for (const auto & arg : args) {
+    for (const auto arg : args) {
         if (arg == args.front()) {
-            ss << (args.size() == 1 ? arg : format("%-7s", (arg + ",").c_str()));
+            if (args.size() == 1) {
+                ss << arg;
+            } else {
+                ss << format("%-7s", arg) << ", ";
+            }
         } else {
             ss << arg << (arg != args.back() ? ", " : "");
         }
     }
-    if (!value_hint.empty()) ss << " " << value_hint;
-    if (!value_hint_2.empty()) ss << " " << value_hint_2;
+    if (value_hint) ss << " " << value_hint;
+    if (value_hint_2) ss << " " << value_hint_2;
     if (ss.tellp() > n_leading_spaces - 3) {
         // current line is too long, add new line
         ss << "\n" << leading_spaces;
@@ -675,7 +679,7 @@ std::vector<llama_arg> gpt_params_parser_init(gpt_params & params, llama_example
                 if (seen_args.find(a) == seen_args.end()) {
                     seen_args.insert(a);
                 } else {
-                    throw std::runtime_error(format("found duplicated argument in source code: %s", a.c_str()));
+                    throw std::runtime_error(format("found duplicated argument in source code: %s", a));
                 }
             }
             options.push_back(std::move(arg));
@@ -693,7 +697,7 @@ std::vector<llama_arg> gpt_params_parser_init(gpt_params & params, llama_example
     add_opt(llama_arg(
         {"--version"},
         "show version and build info",
-        [](gpt_params & params) {
+        [](gpt_params &) {
             fprintf(stderr, "version: %d (%s)\n", LLAMA_BUILD_NUMBER, LLAMA_COMMIT);
             fprintf(stderr, "built with %s for %s\n", LLAMA_COMPILER, LLAMA_BUILD_TARGET);
             exit(0);
@@ -2248,32 +2252,32 @@ std::vector<llama_arg> gpt_params_parser_init(gpt_params & params, llama_example
     add_opt(llama_arg(
         {"--log-test"},
         "Log test",
-        [](gpt_params & params) { log_param_single_parse("--log-test"); }
+        [](gpt_params &) { log_param_single_parse("--log-test"); }
     ));
     add_opt(llama_arg(
         {"--log-disable"},
         "Log disable",
-        [](gpt_params & params) { log_param_single_parse("--log-disable"); }
+        [](gpt_params &) { log_param_single_parse("--log-disable"); }
     ));
     add_opt(llama_arg(
         {"--log-enable"},
         "Log enable",
-        [](gpt_params & params) { log_param_single_parse("--log-enable"); }
+        [](gpt_params &) { log_param_single_parse("--log-enable"); }
     ));
     add_opt(llama_arg(
         {"--log-new"},
         "Log new",
-        [](gpt_params & params) { log_param_single_parse("--log-new"); }
+        [](gpt_params &) { log_param_single_parse("--log-new"); }
     ));
     add_opt(llama_arg(
         {"--log-append"},
         "Log append",
-        [](gpt_params & params) { log_param_single_parse("--log-append"); }
+        [](gpt_params &) { log_param_single_parse("--log-append"); }
     ));
     add_opt(llama_arg(
         {"--log-file"}, "FNAME",
         "Log file",
-        [](gpt_params & params, const std::string & value) { log_param_pair_parse(false, "--log-file", value); }
+        [](gpt_params &, const std::string & value) { log_param_pair_parse(false, "--log-file", value); }
     ));
 #endif // LOG_DISABLE_LOGS
 
diff --git a/common/common.h b/common/common.h
index 1f709271d..b79149da0 100644
--- a/common/common.h
+++ b/common/common.h
@@ -305,10 +305,10 @@ struct gpt_params {
 
 struct llama_arg {
     std::set<enum llama_example> examples = {LLAMA_EXAMPLE_COMMON};
-    std::vector<std::string> args;
-    std::string value_hint; // help text or example for arg value
-    std::string value_hint_2; // for second arg value
-    std::string env;
+    std::vector<const char *> args;
+    const char * value_hint   = nullptr; // help text or example for arg value
+    const char * value_hint_2 = nullptr; // for second arg value
+    const char * env          = nullptr;
     std::string help;
     void (*handler_void)   (gpt_params & params) = nullptr;
     void (*handler_string) (gpt_params & params, const std::string &) = nullptr;
@@ -316,42 +316,42 @@ struct llama_arg {
     void (*handler_int)    (gpt_params & params, int) = nullptr;
 
     llama_arg(
-        const std::initializer_list<std::string> & args,
-        const std::string & value_hint,
+        const std::initializer_list<const char *> & args,
+        const char * value_hint,
         const std::string & help,
         void (*handler)(gpt_params & params, const std::string &)
     ) : args(args), value_hint(value_hint), help(help), handler_string(handler) {}
 
     llama_arg(
-        const std::initializer_list<std::string> & args,
-        const std::string & value_hint,
+        const std::initializer_list<const char *> & args,
+        const char * value_hint,
         const std::string & help,
         void (*handler)(gpt_params & params, int)
     ) : args(args), value_hint(value_hint), help(help), handler_int(handler) {}
 
     llama_arg(
-        const std::initializer_list<std::string> & args,
+        const std::initializer_list<const char *> & args,
         const std::string & help,
         void (*handler)(gpt_params & params)
     ) : args(args), help(help), handler_void(handler) {}
 
     // support 2 values for arg
     llama_arg(
-        const std::initializer_list<std::string> & args,
-        const std::string & value_hint,
-        const std::string & value_hint_2,
+        const std::initializer_list<const char *> & args,
+        const char * value_hint,
+        const char * value_hint_2,
         const std::string & help,
         void (*handler)(gpt_params & params, const std::string &, const std::string &)
     ) : args(args), value_hint(value_hint), value_hint_2(value_hint_2), help(help), handler_str_str(handler) {}
 
-    llama_arg & set_examples(std::set<enum llama_example> examples) {
+    llama_arg & set_examples(std::initializer_list<enum llama_example> examples) {
         this->examples = std::move(examples);
         return *this;
     }
 
-    llama_arg & set_env(std::string env) {
+    llama_arg & set_env(const char * env) {
         help = help + "\n(env: " + env + ")";
-        this->env = std::move(env);
+        this->env = env;
         return *this;
     }
 
@@ -360,8 +360,8 @@ struct llama_arg {
     }
 
     bool get_value_from_env(std::string & output) const {
-        if (env.empty()) return false;
-        char * value = std::getenv(env.c_str());
+        if (env == nullptr) return false;
+        char * value = std::getenv(env);
         if (value) {
             output = value;
             return true;
@@ -370,7 +370,7 @@ struct llama_arg {
     }
 
     bool has_value_from_env() const {
-        return std::getenv(env.c_str());
+        return env != nullptr && std::getenv(env);
     }
 
     std::string to_string();
diff --git a/examples/export-docs/export-docs.cpp b/examples/export-docs/export-docs.cpp
index 86c041a81..a09036dcf 100644
--- a/examples/export-docs/export-docs.cpp
+++ b/examples/export-docs/export-docs.cpp
@@ -22,18 +22,19 @@ static void export_md(std::string fname, llama_example ex) {
         // args
         for (const auto & arg : opt.args) {
         if (arg == opt.args.front()) {
-                file << (opt.args.size() == 1 ? arg : (arg + ", "));
+                file << arg;
+                if (opt.args.size() > 1) file << ", ";
             } else {
                 file << arg << (arg != opt.args.back() ? ", " : "");
             }
         }
         // value hint
-        if (!opt.value_hint.empty()) {
+        if (opt.value_hint) {
             std::string md_value_hint(opt.value_hint);
             string_replace_all(md_value_hint, "|", "\\|");
             file << " " << md_value_hint;
         }
-        if (!opt.value_hint_2.empty()) {
+        if (opt.value_hint_2) {
             std::string md_value_hint_2(opt.value_hint_2);
             string_replace_all(md_value_hint_2, "|", "\\|");
             file << " " << md_value_hint_2;