• Dart

var s = File(Platform.resolvedExecutable).uri.pathSegments.last;

• D

void main(string[] args) {
    string s = args[0].baseName;
}

• Ada

S : String := (Simple_Name (Command_Name));

• C

#ifdef _WIN32
#define PATH_SEP '\\'
#else
#define PATH_SEP '/'
#endif

int main(int argc, char* argv[])
{
    char *s = strchr(argv[0], PATH_SEP);
    s = s ? s + 1 : argv[0];

    return 0;
}

• C++

int main(int argc, char* argv[])
{
    std::cout << std::filesystem::path(argv[0]).filename() << '\n';
}

• C#

var path=Environment.CommandLine;
var s=Path.GetFileName(path);

• Fortran

program p
implicit none
character(len=:),allocatable :: s
integer                      :: stat,l,i,j,k
 call get_command_argument (0,length=l)
 allocate(character(len=l) :: s)
 call get_command_argument (0,s,status=stat)
 if (stat == 0) then
  i=index(s,'/',back=.true.)
  j=index(s,'\',back=.true.)
  k=max(i,j)
  if(k.ne.0)s=s(k+1:)
  print *, "The program's name is " // trim (s)
 endif
end program p

• Go

path := os.Args[0]
s = filepath.Base(path)

• Go

path, err := os.Executable()
if err != nil {
  panic(err)
}
s = filepath.Base(path)

• Haskell

s <- getProgName

• JS

var s = process.argv0;

• Java

String s = System.getProperty("sun.java.command");

• Lua

s = arg[0]

• PHP

$s = $_SERVER['PHP_SELF'];

• Pascal

s := ExtractFileName(ParamStr(0));

• Perl

my $s = $0;

• Python

s = sys.argv[0]

• Ruby

s = $0

• Ruby

s = __FILE__

• Rust

let s = std::env::current_exe()
    .expect("Can't get the exec path")
    .file_name()
    .expect("Can't get the exec name")
    .to_string_lossy()
    .into_owned();

• Rust

fn get_exec_name() -> Option<String> {
    std::env::current_exe()
        .ok()
        .and_then(|pb| pb.file_name().map(|s| s.to_os_string()))
        .and_then(|s| s.into_string().ok())
}

fn main() -> () {
    let s = get_exec_name().unwrap();
    println!("{}", s);
}