I am new to Lua programming language. I installed Lua for Windows v5.1.5-52. I want to use luacom library to run shell script. Here is my code,
local luacom = require('luacom');
local shell = luacom.CreateObject("WScript.Shell")
shell:Run ('echo 123', 0)
which throws the following error:
lua: COM exception:(.\src\library\tLuaCOM.cpp,398):The system cannot
find the file specified.
I looked for tLuaCOM.cpp file, but could not find it, not even folder src. Though I found luacom.dll in clibs folder.
Is there any workaround with this problem?
tLuaCOM.cpp is a luacom source file, so it's probably not on your PC, except you've build it yourself.
The error comes from one of the calls - either CreateObject() or Run.
The Run Method (Windows Script Host) helps says that it starts processes:
The Run method starts a program running in a new Windows process.
but echo is a shell command, not an executable, so you have to start an instance of the Windows command interpreter and pass your command like:
shell:Run('cmd /c "echo 123"')
Related
I installed flatpak using guix, but it segfaulted on startup. I wanted to debug it, but guix installs a wrapper script for flatpak, so I get this error when trying to run it under gdb:
"/home/user/.guix-profile/bin/flatpak": not in executable format: file format not recognized
and I tried to edit the wrapper script to call gdb, but this wrapper script is not even editable by root, because it is owned by root and has read-only permissions.
Simply copy the script to your current working directory:
cp /home/user/.guix-profile/bin/flatpak .
Mark it as writable:
chmod +w flatpak
Edit the script with your favourite text editor, to replace the string exec -a with exec gdb --args.
And finally, run it with any arguments you provided before, when it misbehaved:
./flatpak remote-add flathub https://flathub.org/repo/flathub.flatpakrepo
In this particular case, this wasn't immediately super-useful, because a debug symbol output hasn't been built for this package. But at least I could get a backtrace out of gdb.
I created a c++ programm that works with ros. The first step would be to open a roscore in a terminal and move on from there. I do so with system("roscore &");
I compiled my file and can run it just fine with ./file.
However, I want to be able to run it as an application (double click). I created a .desktop file and the program shows up in my application list. When i start it though, all I get is a terminal that opens with the message
sh: 1: roscore: not found
etc.
The same applies for the roslaunch commands. I also fork and exec a roslaunch command, which does not work as well.
I tried system("ls"); which worked. All cout messages work as well.
Any idea what is wrong here?
roscore executable is not located in std paths (/bin:/usr/bin:). Use the absolute path - system("/path/to/roscore &")
I am trying to have my program change directory (to where the user wishes to) but I am unable to navigate there and create a file? It appears that I am able to navigate there but when I get to the next system call it returns back to the current directory
Is there a way to set where my program cwd is pointing to?
std::string s1 = "cd " + userDirectory;
system(s1.c_str());
system("dir > test.txt");
SetCurrentDirectory Win32 on Windows.
chdir() / _chdir for POSIX (a common C API available on many OS:es).
boost/std::filesystem current_path() for C++ (std in C++17).
The system function starts a new command interpreter as a new process. And then runs the commands in that command interpreter. And as the cd command is a built-in command it will only apply to that command interpreter process, not your process.
You have a couple of solutions you can try:
Put the commands (cd and dir and everything else) in to a script file that you run.
Change the working directory of your process.
On Windows you can change working directory using SetCurrentDirectoryW function.
How can I open a new terminal from C ++ code and write inside it. I know how to open new terminal by using system command (system("/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal")), but do not know how to write string in it ? I'm working on an operating system mac os.
In Linux you can do so
std :: string cmd = "gnome-terminal-x sh-c 'ls-l; exec bash'";
system (cmd.c_str ());
how to do it in the mac os ?
Your basic mechanism of calling system() should still work, you just need a different command.
One way to do this is by running AppleScript from the command line via osascript. You can use the "AppleScript Editor" application (and use the Library command in its Window menu) to learn more about all the commands that can be given to programs in this way.
For example, to make the Mac Terminal run top, I could invoke this command line:
/usr/bin/osascript -e 'tell application "Terminal" to do script "top"'
Similarly, if I'd already written an entire file of commands to run, I could give it a .command extension and ask Terminal to open the file instead:
/usr/bin/osascript -e 'tell application "Terminal" to open "/Users/me/Desktop/MyFile.command"'
I’ve produced a C++ program in Eclipse running on Redhat, which compiles and runs fine through Eclipse.
I thought that to run it separately to Eclipse you use the build artifact which is in the directory set via the project’s properties.
However this executable doesn’t run (I know it’s an executable as I’ve set it to be an executable via the project’s properties and it shows up as such via the ls command and the file explorer).
When attempting to run it using the executable’s name, I get the error:
bash: <filename>: command not found
When attempting to run it as a bash file:
<filename>: <filename>: cannot execute binary file
And when running it with "./" before the file name, nothing happens. Nothing new appears in the running processes and the terminal just goes to the next line as though I’d just pressed enter with no command.
Any help?
You've more or less figure out the first error yourself. when you just run <filename> , it is not in your PATH environment variable, so you get "command not found". You have to give a full or relative path when to the program in order to run it, even if you're in the same directory as the program - you run it with ./<filename>
When you do run your program, it appears to just exit as soon as you start it - we can't help much with that without knowing what the program does or see some code.
You can do some debugging, e.g. after the program just exits run echo $? to see if it exited with a particular exit value, or run your program using the strace tool to see what it does (or do it the usual way, insert printf debugging, or debug it with gdb)