China DOS Union

Right now I have a text file, and inside it there is one very long line. The contents of the line are character, tab, character, tab.....

After opening it with Notepad, I found that this line is already displayed as 3 lines (word wrap is not enabled).
(When opened with excle I found it is 1 line, and it has already extended to column IG, with probably more than 270 tabs)

So would sed treat this as one line or 3 lines?

Also, how does the sed command recognize tabs (what is the wildcard for tabs)?

Use a regular expression to identify lines; the line-ending symbol is $. The several lines you see are just a display issue. You can try opening it with ultraedit and have a look.

Tabs are generally represented with \t.

After checking the hex, I found that this line really has only one 0D 0A
But why can't sed "line number"d filename delete it?
The line number is the one shown in the status bar.

Could it be that the sed command was written incorrectly?

Under unix it is generally written like this:
sed 'm,nd' means deleting the content from line m through line n.

1 line
\t