sed: how to replace CR and/or LF with "\r" "\n", so any file will be in one line - windows

Question

I have files like
aaa
bbb
ccc
I need them to sed into aaa\r\nbbb\r\nccc
It should work either for unix and windows replacing them with \r or \r\n accordingly
The problem is that sed adds \n at the end of line but keeps lines separated. How can I fix it?

Answer 1

These two commands together should do what you want:
sed ':a;N;$!ba;s/\r/\\r/g'
sed ':a;N;$!ba;s/\n/\\n/g'
Pass your input file through both to get the output you want. Theres probably a way to combine them into a single expression.
Stolen and Modified from this question:
How can I replace a newline (\n) using sed?

Answer 2

It's possible to merge lines in sed, but personally, I consider needing to change line breaks a sign that it's time to give up on sed and use a more powerful language instead. What you want is one line of perl:
perl -e 'undef $/; while (<>) { s/\n/\\n/g; s/\r/\\r/g; print $_, "\n" }'
or 12 lines of python:
#! /usr/bin/python
import fileinput
from sys import stdout
first = True
for line in fileinput.input(mode="rb"):
if fileinput.isfirstline() and not first:
stdout.write("\n")
if line.endswith("\r\n"): stdout.write(line[:-2] + "\\r\\n")
elif line.endswith("\n"): stdout.write(line[:-1] + "\\n")
elif line.endswith("\r"): stdout.write(line[:-1] + "\\r")
first = False
if not first: stdout.write("\n")
or 10 lines of C to do the job, but then a whole bunch more because you have to process argv yourself:
#include <stdio.h>
void process_one(FILE *fp)
{
int c;
while ((c = getc(fp)) != EOF)
if (c == '\n') fputs("\\n", stdout);
else if (c == '\r') fputs("\\r", stdout);
else putchar(c);
fclose(fp);
putchar('\n');
}
int main(int argc, char **argv)
{
FILE *cur;
int i, consumed_stdin = 0, rv = 0;
if (argc == 1) /* no arguments */
{
process_one(stdin);
return 0;
}
for (i = 1; i < argc; i++)
{
if (argc[i][0] == '-' && argc[i][1] == 0)
{
if (consumed_stdin)
{
fputs("cannot read stdin twice\n", stderr);
rv = 1;
continue;
}
cur = stdin;
consumed_stdin = 1;
}
else
{
cur = fopen(ac[i], "rb");
if (!cur)
{
perror(ac[i]);
rv = 1;
continue;
}
}
process_one(cur);
}
return rv;
}

Answer 3

awk '{printf("%s\\r\\n",$0)} END {print ""}' file

Answer 4

tr -s '\r' '\n' <file | unix2dos
EDIT (it's been pointed out that the above misses the point entirely! •///•)
tr -s '\r' '\n' <file | perl -pe 's/\s+$/\\r\\n/'
The tr gets rid of empty lines and dos line endings. The pipe means two processes—good on modern hardware.