Shell Programming and Scripting

I have few files in unix which are in dos format. While I am copying these files, ^M, ^@, etc characters are being generated.

I tried dos2unix command in Linux and it doesn't work.
I tried sed to remove these characters but they won't go.
I came to about this 'tr' command and tried to use it but when I try to use it, still it removes M elsewhere in the file but not ^M.

Please advise in how to get rid of these caret characters.

Thanks
Chiru

For sure you removed uppercase M characters at the beginning of the line.

The reason why you failted to remove ^M is because you type it as 2 characters.

In the file however it is a single character.

You can remiove them e.g. in "vi".

Once inside "vi" you can create ^M as a single character by typing first CTRL-V and next CTRL-M.

Make sure you are in command mode (press ESC if necessary) and next you type:

:%s/^M//g

Make sure the ^M is a single character created as mentioned above.

This is just kind of weird. I was going to ask about this very thing when I came to the board, and the question is up on top.

I was wondering about using sed to do the trick. I am running Linux with GNU sed version 4.1.5. Anyway, I had a file which was peppered with ^M characters. I tried this:

Code:

sed -i 's/^M/\n/g' some_prog

But it did not seem to do the trick. What did I do wrong?

edit::

Ah - I just tried doing <CTRL-V> <CTRL-M> and it worked. So thanks sb008..

So my next question is about the <CTRL-V> <CTRL-M> sequence. Why is <CTRL-V> necessary? What is happening when it is used?

Just for a second thought you could as well accomplish the same task with sed as well. You dont have to replace ^M with the new line character(\n) just try removing the ^M character.

sed 's/^M//g' filename

As sb008 said

Ctrlv and ctrlM procedure is usefule to remove "^M" ...sometimes "sed" won't work.. I faced this problem earlier

>Just for a second thought you could as well accomplish the same task with sed >as well. You dont have to replace ^M with the new line character(\n) just try >removing the ^M character.

>sed 's/^M//g' filename

Indeed - that is what I actually wanted rather than inserting all the newlines.

I've had to use this command-line often. It will strip carriage returns (^M) and convert null bytes (^@) into spaces.

cat dos.file | tr -d '\r' | tr '\0' ' ' > unix.file