在bash shell中循环

Question

I read a file like this:

while read line; do
    echo "$line"
done < file.txt

Sometimes, I can't read the last line.
Open the file with VIM, and exec ":set list", then I can see a "$" at the end of each line.
But, when I exec "cat file.txt":

$ cat file.txt
aa
bb$

The last line "bb" and the "$" are in the same line.
I think it's a problem.
How can I use "while" to read all lines?
ps:Can vim show newline like \\n and return like \\r?

I'm a beginner, help!

Answer 1

It is most likely because of missing \\n from end of line OR presence of \\r in a line.

You can test it by this command:

cat -vte file

To remove \\r from end use this sed:

sed -i.bak 's/'$'\r''$//' file

Answer 2

The way Vim alerts you to this condition (a missing newline ( \\n ) character in the last line) is during opening, where [noeol] will be in the message.

:edit foo
"foo" [noeol] 3L, 42C

You can also check later via

:setlocal eol?

To fix this retroactively (meaning you cannot modify the file's source to avoid creating such files), just :write the file from Vim; it'll insert the final newline automatically.