// Check that we have enough command line arguments and
// if not abort with an error message.
if (args.size != 2)
    punt("command line is: search pattern file");

// Move arguments to variables with better names
string pattern = args[0];
string fileName = args[1];

// Open a file to read, and then loop through each line.
file f = fileOpen(fileName, "r"); // "r" is for read
for (line in f.readLine())
    {
    // The line.find call returns the starting index of the
    // pattern in the line, or -1 if not found.
    if (line.find(pattern) >= 0)
        prin(line);	// Line already has end of line so prin
    }