Using python to write text files with DOS line endings on linux

Question

I want to write text files with DOS/Windows line endings '\r\n' using python running on Linux. It seems to me that there must be a better way than manually putting a '\r\n' at the end of every line or using a line ending conversion utility. Ideally I would like to be able to do something like assign to os.linesep the separator that I want to use when writing the file. Or specify the line separator when I open the file.

Answer 1

For Python 2.6 and later, the open function in the io module has an optional newline parameter that lets you specify which newlines you want to use.

For example:

import io
with io.open('tmpfile', 'w', newline='\r\n') as f:
    f.write(u'foo\nbar\nbaz\n')

will create a file that contains this:

foo\r\n
bar\r\n
baz\r\n

Answer 2

you can look at this PEP for some reference.

Update:

@OP, you can try creating something like this

import sys
plat={"win32":"\r\n", 'linux':"\n" } # add macos as well
platform=sys.platform
...
o.write( line + plat[platform] )

Answer 3

Just write a file-like that wraps another file-like and which converts \n to \r\n on write.

For example:

class ForcedCrLfFile(file):
    def write(self, s):
        super(ForcedCrLfFile, self).write(s.replace(r'\n', '\r\n'))

Answer 4

Here's a python script I wrote. It recurses from a given directory, replacing all \n line endings with \r\n endings. Use it like this:

unix2windows /path/to/some/directory

It ignores files in folders beginning with a '.'. It also ignores files that it thinks are binary files, using the approach given by J.F. Sebastian in this answer. You can filter further by using the optional regex positional argument:

unix2windows /path/to/some/directory .py$

Here's the script in full. For the avoidance of doubt, my parts are licensed under the MIT licence.

#!/usr/bin/python
import sys
import os
import re
from os.path import join

textchars = bytearray({7,8,9,10,12,13,27} | set(range(0x20, 0x100)) - {0x7f})
def is_binary_string(bytes):
    return bool(bytes.translate(None, textchars))

def is_binary_file(path):    
    with open(path, 'rb') as f:
        return is_binary_string(f.read(1024))

def convert_file(path):
    if not is_binary_file(path):
        with open(path, 'r') as f:
            text = f.read()
        print path
    with open(path, 'wb') as f:
        f.write(text.replace('\r', '').replace('\n', '\r\n'))

def convert_dir(root_path, pattern):
    for root, dirs, files in os.walk(root_path):
        for filename in files:
            if pattern.search(filename):
                path = join(root, filename)
                convert_file(path)

        # Don't walk hidden dirs
        for dir in list(dirs):
            if dir[0] == '.':
                dirs.remove(dir)

args = sys.argv
if len(args) <= 1 or len(args) > 3:
    print "This tool recursively converts files from Unix line endings to"
    print "Windows line endings"
    print ""
    print "USAGE: unix2windows.py PATH [REGEX]"
    print "Path:             The directory to begin recursively searching from"
    print "Regex (optional): Only files matching this regex will be modified"
    print ""    
else:
    root_path = sys.argv[1]
    if len(args) == 3:
        pattern = sys.argv[2]
    else:
        pattern = r"."
    convert_dir(root_path, re.compile(pattern))

Answer 5

You could write a function that converts text then writes it. For example:

def DOSwrite(f, text):
    t2 = text.replace('\n', '\r\n')
    f.write(t2)
#example
f = open('/path/to/file')
DOSwrite(f, "line 1\nline 2")
f.close()