[SOLVED] replace \n with blank but keep \r\n using sed/tr

Issue

My input looks like:

Line 1\n 
More Line 1\r\n
Line 2\n 
More Line 2\r\n

I want to produce

Line 1 More Line 1\r\n
Line 2 More Line 2\r\n

Using sed or tr. I have tried the following and it does not work:

sed -e 's/([^\r])\n/ /g' in_file > out_file

The out_file still looks like the in_file. I also have an option of writing a python script.

Solution

Try:

sed '/[^\r]$/{N; s/\n/ /}' in_file

How it works:

• /[^\r]$/

  This selects only lines which do not have a carriage-return before the newline character. The commands which follow in curly braces are only executed for lines which match this regex.

• N

  For those selected lines, this appends a newline to it and then reads in the next line and appends it.

• s/\n/ /

  This replaces the unwanted newline with a space.

Discussion

When sed reads in lines one at a time but it does not read in the newline character which follows the line. Thus, in the following, \n will never match:

sed -e 's/([^\r])\n/ /g'

We can match [^\r]$ where $ signals the end-of-the-line but this still does not include the \n.

This is why the N command is used above to read in the next line, appending it to the pattern space after appending a newline. This makes the newline visible to us and we can remove it.

Answered By - John1024

Answer Checked By - Terry (WPSolving Volunteer)