It looks like you have a test.txt file with MacIntosh line endings?

With my test1.txt below, which has different octets than yours, things work better, but not perfect. There is still an odd behavior of the Tk Text widget inserting spaces. Its some sort of encoding problem, which eludes me. :-(

test1.txt

1
2
3
4
5
6
7
8
9
a
b
c
d
e
f
[download]

Running the program with your test.txt gives a Tk::Text output as

1
/x(d)
3
/x(d)
5
/x(d)
7
/x(d)
9
/x(d)
b
/x(d)
d
/x(d)
f
/x(d)
[download]

Running test1.txt, which has a unicode octet difference gives

1
3
5
7
9
b
d
f
[download]

Notice your sample text.txt shows /x(d) If I double quote "@contents", then I get a good result with my test1.txt , but an odd spce gets put in.

1
 2
 3
 4
 5
 6
 7
 8
 9
 a
 b
 c
 d
 e
 f
[download]