So, I am confused by this sort routine

[ghostmachine4]

Source :Sorting text with numbers - Sorting that handles numbers as numbers not text

So , the little help text says

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...
test [n]

  n     Specifies the character number, n, to
        begin each comparison.  3 indicates that
        each comparison should begin at the 3rd
        character in each line.  Lines with fewer
        than n characters collate before other lines.
        By default comparisons start at the first
        character in each line.

It says "n" specifies the position of character to start sorting. So let's say we have this in a file

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abc10def3
abc900def4
abc29def3
ab2234defa
ab2234defv

without specifying the "n" character, it gives supposedly correct results

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C:\work>type file | test.bat
ab2234defa  <== since "2" is at 3rd position
ab2234defv  <=== since "v" is greater than "a" at the last position
abc10def3
abc29def3  <=== the rest are at 4th position
abc900def4

However, when tested with n = 4 for example

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C:\work>type file | test.bat 4
abc10def3
abc900def4 <=== why is 900 here ie, greater than "29" below? 
abc29def3
ab2234defa
ab2234defv

this gives incorrect results, since starting from 4th position, these should be the correct result

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abc10def3 <== starting from 4th position "10" is smallest
abc29def3 <=== then 29
ab2234defa  <== then 234
ab2234defv  <== then 234 and last character "v" is greater than previous "a"
abc900def4  <== 900 is the highest.

Some one please clear up my confusion.

[DosItHelp]

"Specifies the character number, n, to begin each comparison." means that n=4 indicates that each comparison should begin at the 4th character in each line.
Adding a space after the 4th character should clarify:

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abc1  0def3      <== 0
abc9  00def4     <== 0 results from 00, 4 is greater than 3 
abc2  9def3      <== 9
ab22  34defa     <== 34
ab22  34defv     <== 34, v is greater that a

Makes sense?

[ghostmachine4]

"Specifies the character number, n, to begin each comparison." means that n=4 indicates that each comparison should begin at the 4th character in each line.
Adding a space after the 4th character should clarify:

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abc1  0def3      <== 0
abc9  00def4     <== 0 results from 00, 4 is greater than 3 
abc2  9def3      <== 9
ab22  34defa     <== 34
ab22  34defv     <== 34, v is greater that a

Makes sense?

Well, it makes sense if the statement says "each comparison should begin after the nth character in each line." instead of "each comparison should begin at the 4th character in each line." . With "begin at" , I take it to mean literally starting from the 4th character. In your example, I view it as starting from the 5th character. I really should have specified n=3 if I want it to start at 4th character. thanks for clarifying.

[DosItHelp]

Ok, I see what you mean. This has been fixed now, character position starts with 1 now and not with 0.
Thanks a lot for pointing this out!