Converts CRLF to LF in a file or recursively in all files of a directory

crlf2lf

#!/usr/bin/env python
import argparse, os, sys

(
    NO_ERR,
    READ_ERR,
    WRITE_ERR,
    BACKUP_ERR,
) = range(4)

ERR_HDR = {
    READ_ERR:   'ERROR reading file %s',
    WRITE_ERR:  'ERROR writing file %s',
    BACKUP_ERR: 'ERROR backing up file %s',
}

ERR_EXIT = -1


def bak_name(name):
    bak = name +'.bak'
    i = 1
    while os.path.isfile(bak):
        bak ='%s.bak.%d' % (name, i)
        i += 1
    return bak

def crlf2lf(file_name, backup=False):
    try:
        with open(file_name, 'r') as f:
            text = f.read()
    except e:
        return READ_ERR, e

    try:
        if backup:
            os.rename(file_name, file_name+'.bak')
    except e:
        return BACKUP_ERR, e

    try:
        with open(file_name, 'w') as f:
            text = text.replace('\r\n', '\n')
            f.write(text)
    except e:
        return WRITE_ERR, e

    return NO_ERR, None

def process_file(file_name, backup):
    err_type, err_msg = crlf2lf(file_name, backup)
    if err_type != NO_ERR:
        print('%s\n%s' % (ERR_HDR[err_type] % file_name, err_msg))
        return ERR_EXIT
    return 0

def process_dir(dir_name, backup):
    exit_code = 0
    for base, _, file_names in os.walk(dirname):
        for file_name in file_names:
            exit_code |= process_file(os.path.join(base, file_name), backup)
    return exit_code

def main():
    parser = argparse.ArgumentParser(
        description='converts CRLF to LF in a file or recursively in all files of a directory')
    parser.add_argument(
        'path', default='.', type=str,
        help='source file or directory')
    parser.add_argument(
        '--backup', default=False, type=bool,
        help='backup original file')
    args = parser.parse_args()

    if os.path.isfile(args.path):
        exit(process_file(args.path, args.backup))

    if os.path.isdir(args.path):
        exit(process_dir(args.path, args.backup))

    print('`%s` is not an existing file or directory' % path)
    exit(ERR_EXIT)

if __name__ == '__main__':
    main()