Print main command along with subcommand on help page

README.md

@@ -895,7 +895,7 @@ Subcommands:
   submodule     Initialize, update or inspect submodules
 
 foo@bar:/home/dev/$ ./git add --help
-Usage: add [-h] files
+Usage: git add [-h] files
 
 Add file contents to the index
 
@@ -907,7 +907,7 @@ Optional arguments:
   -v, --version	prints version information and exits
 
 foo@bar:/home/dev/$ ./git commit --help
-Usage: commit [-h] [--all] [--message VAR]
+Usage: git commit [-h] [--all] [--message VAR]
 
 Record changes to the repository
 
@@ -918,7 +918,7 @@ Optional arguments:
   -m, --message	Use the given <msg> as the commit message.
 
 foo@bar:/home/dev/$ ./git submodule --help
-Usage: submodule [-h] {update}
+Usage: git submodule [-h] {update}
 
 Initialize, update or inspect submodules
 
@@ -957,7 +957,7 @@ Optional arguments:
   -v, --version prints version information and exits
 
 foo@bar:/home/dev/$ ./main hidden -h
-Usage: hidden [--help] [--version] files
+Usage: test hidden [--help] [--version] files
 
 Positional arguments:
   files         [nargs: 0 or more]

include/argparse/argparse.hpp

@@ -2010,7 +2010,7 @@ class ArgumentParser {
     std::stringstream stream;
 
     std::string curline("Usage: ");
-    curline += this->m_program_name;
+    curline += this->m_parser_path;
     const bool multiline_usage =
         this->m_usage_max_line_width < std::numeric_limits<std::size_t>::max();
     const size_t indent_size = curline.size();

test/test_help.cpp

@@ -244,3 +244,12 @@ TEST_CASE("multiline usage, break on mutex") {
         "               [--will-go-on-new-line]\n"
         "               [--on-a-dedicated-line]");
 }
+
+TEST_CASE("Usage output with subparser") {
+    argparse::ArgumentParser program("program");
+    argparse::ArgumentParser sub("sub");
+    program.add_subparser(sub);
+    // std::cout << "DEBUG:" << program.usage() << std::endl;
+    REQUIRE(program.usage() == "Usage: program [--help] [--version] {sub}");
+    REQUIRE(sub.usage() == "Usage: program sub [--help] [--version]");
+}