Regular expression: match text before end of line

Question

I have a file that looks like this:

J6      INT-00113G  227.905    5.994  180  ~!@#$%&^)
J3      INT-00113G  227.905 -203.244  180  12341341312315
U13     EXCLUDES    -42.210  181.294  180  QFP128
U3      IC-00276G     5.135  198.644  90   B%GA!@-48
U12     IC-00270G  -123.610 -201.594  0    SOP8_000
J1      INT-00112G  269.665  179.894  180  SOIC16_1
J2      INT-00112G  269.665  198.144  180  SOIC16-_2
..      ..........  .......  .......  ...  ................

And I would like to match the final value in the 6th column to remove it from the list. The length of the value in the 6th column is not defined and can contain any character. So what I would like to do is match the final value before the space. or just the end of the line.

---

CODE:

        // Reads the lines in the file to format.
        var fileReader = File.OpenText(filePath + "\\Remove Package 1 Endings.txt");

        // Creates a list for the lines to be stored in.
        var fileList = new List<string>();

        // Adds each line in the file to the list.
        while (true)
        {
            var line = fileReader.ReadLine();
            if (line == null)
                break;

            fileList.Add(line);
        }

        var mainResult = new List<string>();
        var theResult = new List<string>();

        foreach (var mainLine in fileList)
            mainResult.Add(string.Join(" ", mainLine));

        foreach (var theLine in mainResult)
        {
            // PLACEMENT ONE Regex
            Match theRegex = Regex.Match(theLine, @"insert the regex here!");

            if (theRegex.Success)
                theResult.Add(string.Join(" ", theLine));
        }

        // Removes the matched values from both of the Regex used above.
        List<string> userResult = mainResult.Except(theResult).ToList();

        // Prints the proper values into the assigned RichTextBoxes.
        foreach (var line in userResult)
            richTextBox2.AppendText(line + "\n");

What I'm trying to do is make the file look like this:

J6      INT-00113G  227.905    5.994  180
J3      INT-00113G  227.905 -203.244  180
U13     EXCLUDES    -42.210  181.294  180
U3      IC-00276G     5.135  198.644  90
U12     IC-00270G  -123.610 -201.594  0
J1      INT-00112G  269.665  179.894  180
J2      INT-00112G  269.665  198.144  180

---

Question:

• Can someone help come up with a regex for this?

EDIT:

ADDED CODE:

        var lines = new List<string>(File.ReadAllLines(filePath + "\\Remove Package 1 Endings.txt"));
        for (int i = 0; i < lines.Count; i++)
        {
            var idx = lines[i].LastIndexOf(" ");

            if (idx != -1)
                lines[i] = lines[i].Remove(idx);

            richTextBox1.AppendText(lines[i] + Environment.NewLine
        }

Answer 1

\S+$ , . ( , ... #, ?, (?m) , .).

\S -
+ - ,
$ - , .

EDIT: , .

(, , , , , ).

Answer 2

, , ; , , , , (, , ), , :

var lines = new List<string>(File.ReadAllLines(path));
for (int i = 0; i < lines.Count; i++) 
{
    var idx = lines[i].LastIndexOf(" ");   
    if (idx != -1)
    {     
        lines[i] = lines[i].Remove(idx);
    }
}

, , , , - .

Answer 3

, , :

\s+([\S]*)$