C programming basics: Command line arguments

by amitsaha 11 years ago

GNU/Linux ◆ xterm-256color ◆ bash 1115 views

Learn the very basics of command line arguments.

You should realize that argc and argv are just variables. You can use any other variable names in their place. The important bit however is that you should always have the integer variable first, and then the array of arguments (which you can also declare as char *argv[] - i.e. an array of pointers).

The first argument is always the program name, i.e. ./prog in this case.

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You can download this recording in asciicast v2 format, as a .cast file.

Download

Replay in terminal

You can replay the downloaded recording in your terminal using the asciinema play command:

asciinema play 1925.cast

If you don't have asciinema CLI installed then see installation instructions.

Use with stand-alone player on your website

Download asciinema player from the releases page (you only need .js and .css file), then use it like this:

<!DOCTYPE html>
<html>
<head>
  <link rel="stylesheet" type="text/css" href="asciinema-player.css" />
</head>
<body>
  <div id="player"></div>
  <script src="asciinema-player.min.js"></script>
  <script>
    AsciinemaPlayer.create(
      '/assets/1925.cast',
      document.getElementById('player'),
      { cols: 172, rows: 47 }
    );
  </script>
</body>
</html>

See asciinema player quick-start guide for full usage instructions.

While this site doesn't provide GIF conversion at the moment, you can still do it yourself with the help of asciinema GIF generator utility - agg.

Once you have it installed, generate a GIF with the following command:

agg https://asciinema.org/a/1925 demo.gif

Or, if you already downloaded the recording file:

agg demo.cast demo.gif

Check agg --help for all available options. You can change font family and size, select color theme, adjust speed and more.

See agg manual for full usage instructions.