dos2unix(1) 2014-06-09 dos2unix(1)
dos2unix - DOS/Mac to Unix and vice versa text file format converter
dos2unix [options] [FILE ...] [-n INFILE OUTFILE ...]
unix2dos [options] [FILE ...] [-n INFILE OUTFILE ...]
The Dos2unix package includes utilities "dos2unix" and "unix2dos" to convert plain text
files in DOS or Mac format to Unix format and vice versa.
In DOS/Windows text files a line break, also known as newline, is a combination of two
characters: a Carriage Return (CR) followed by a Line Feed (LF). In Unix text files a line
break is a single character: the Line Feed (LF). In Mac text files, prior to Mac OS X, a
line break was single Carriage Return (CR) character. Nowadays Mac OS uses Unix style (LF)
Binary files are automatically skipped, unless conversion is forced.
Non-regular files, such as directories and FIFOs, are automatically skipped.
Symbolic links and their targets are by default kept untouched. Symbolic links can
optionally be replaced, or the output can be written to the symbolic link target.
Symbolic links on Windows are not supported. Windows symbolic links always replaced,
keeping the targets unchanged.
Dos2unix was modelled after dos2unix under SunOS/Solaris and has similar conversion modes.
-- Treat all following options as file names. Use this option if you want to convert
files whose names start with a dash. For instance to convert a file named "-foo", you
can use this command:
dos2unix -- -foo
Or in new file mode:
dos2unix -n -- -foo out.txt
Convert only line breaks. This is the default conversion mode.
Conversion between DOS and ISO-8859-1 character set. See also section CONVERSION
Use Windows code page 1252 (Western European).
Use DOS code page 437 (US). This is the default code page used for ISO conversion.
Use DOS code page 850 (Western European).
Use DOS code page 860 (Portuguese).
Use DOS code page 863 (French Canadian).
Use DOS code page 865 (Nordic).
-7 Convert 8 bit characters to 7 bit space.
-c, --convmode CONVMODE
Set conversion mode. Where CONVMODE is one of: ascii, 7bit, iso, mac with ascii being
Force conversion of binary files.
Display help and exit.
Keep the date stamp of output file same as input file.
Display program's license.
Add additional newline.
dos2unix: Only DOS line breaks are changed to two Unix line breaks. In Mac mode only
Mac line breaks are changed to two Unix line breaks.
unix2dos: Only Unix line breaks are changed to two DOS line breaks. In Mac mode Unix
line breaks are changed to two Mac line breaks.
Write an UTF-8 Byte Order Mark in the output file. Never use this option when the
output encoding is other than UTF-8. See also section UNICODE.
-n, --newfile INFILE OUTFILE ...
New file mode. Convert file INFILE and write output to file OUTFILE. File names must
be given in pairs and wildcard names should not be used or you will lose your files.
The person who starts the conversion in new file (paired) mode will be the owner of
the converted file. The read/write permissions of the new file will be the permissions
of the original file minus the umask(1) of the person who runs the conversion.
-o, --oldfile FILE ...
Old file mode. Convert file FILE and overwrite output to it. The program defaults to
run in this mode. Wildcard names may be used.
In old file (in-place) mode the converted file gets the same owner, group, and
read/write permissions as the original file. Also when the file is converted by
another user who has write permissions on the file (e.g. user root). The conversion
will be aborted when it is not possible to preserve the original values. Change of
owner could mean that the original owner is not able to read the file any more. Change
of group could be a security risk, the file could be made readable for persons for
whom it is not intended. Preservation of owner, group, and read/write permissions is
only supported on Unix.
Quiet mode. Suppress all warnings and messages. The return value is zero. Except when
wrong command-line options are used.
Skip binary files (default).
Follow symbolic links and convert the targets.
Replace symbolic links with converted files (original target files remain unchanged).
Keep symbolic links and targets unchanged (default).
Display version information and exit.
In normal mode line breaks are converted from DOS to Unix and vice versa. Mac line breaks
are not converted.
In Mac mode line breaks are converted from Mac to Unix and vice versa. DOS line breaks are
To run in Mac mode use the command-line option "-c mac" or use the commands "mac2unix" or
Conversion modes ascii, 7bit, and iso are similar to those of dos2unix/unix2dos under
In mode "ascii" only line breaks are converted. This is the default conversion mode.
Although the name of this mode is ASCII, which is a 7 bit standard, the actual mode is
8 bit. Use always this mode when converting Unicode UTF-8 files.
In this mode all 8 bit non-ASCII characters (with values from 128 to 255) are
converted to a 7 bit space.
iso Characters are converted between a DOS character set (code page) and ISO character set
ISO-8859-1 (Latin-1) on Unix. DOS characters without ISO-8859-1 equivalent, for which
conversion is not possible, are converted to a dot. The same counts for ISO-8859-1
characters without DOS counterpart.
When only option "-iso" is used dos2unix will try to determine the active code page.
When this is not possible dos2unix will use default code page CP437, which is mainly
used in the USA. To force a specific code page use options "-437" (US), "-850"
(Western European), "-860" (Portuguese), "-863" (French Canadian), or "-865" (Nordic).
Windows code page CP1252 (Western European) is also supported with option "-1252". For
other code pages use dos2unix in combination with iconv(1). Iconv can convert between
a long list of character encodings.
Never use ISO converion on Unicode text files. It will corrupt UTF-8 encoded files.
Convert from DOS default code page to Unix Latin-1
dos2unix -iso -n in.txt out.txt
Convert from DOS CP850 to Unix Latin-1
dos2unix -850 -n in.txt out.txt
Convert from Windows CP1252 to Unix Latin-1
dos2unix -1252 -n in.txt out.txt
Convert from Windows CP1252 to Unix UTF-8 (Unicode)
iconv -f CP1252 -t UTF-8 in.txt | dos2unix > out.txt
Convert from Unix Latin-1 to DOS default code page.
unix2dos -iso -n in.txt out.txt
Convert from Unix Latin-1 to DOS CP850
unix2dos -850 -n in.txt out.txt
Convert from Unix Latin-1 to Windows CP1252
unix2dos -1252 -n in.txt out.txt
Convert from Unix UTF-8 (Unicode) to Windows CP1252
unix2dos < in.txt | iconv -f UTF-8 -t CP1252 > out.txt
See also <http://czyborra.com/charsets/codepages.html> and
There exist different Unicode encodings. On Unix and Linux Unicode files are typically
encoded in UTF-8 encoding. On Windows Unicode text files can be encoded in UTF-8, UTF-16,
or UTF-16 big endian, but are mostly encoded in UTF-16 format.
Unicode text files can have DOS, Unix or Mac line breaks, like regular text files.
All versions of dos2unix and unix2dos can convert UTF-8 encoded files, because UTF-8 was
designed for backward compatiblity with ASCII.
Dos2unix and unix2dos with Unicode UTF-16 support, can read little and big endian UTF-16
encoded text files. To see if dos2unix was built with UTF-16 support type "dos2unix -V".
The Windows versions of dos2unix and unix2dos convert UTF-16 encoded files always to UTF-8
encoded files. Unix versions of dos2unix/unix2dos convert UTF-16 encoded files to the
locale character encoding when it is set to UTF-8. Use the locale(1) command to find out
what the locale character encoding is.
Because UTF-8 formatted text files are well supported on both Windows and Unix, dos2unix
and unix2dos have no option to write UTF-16 files. All UTF-16 characters can be encoded in
UTF-8. Conversion from UTF-16 to UTF-8 is without loss. UTF-16 files will be skipped on
Unix when the locale character encoding is not UTF-8, to prevent accidental loss of text.
When an UTF-16 to UTF-8 conversion error occurs, for instance when the UTF-16 input file
contains an error, the file will be skipped.
ISO and 7-bit mode conversion do not work on UTF-16 files.
Byte Order Mark
On Windows Unicode text files typically have a Byte Order Mark (BOM), because many Windows
programs (including Notepad) add BOMs by default. See also
On Unix Unicode files typically don't have a BOM. It is assumed that text files are
encoded in the locale character encoding.
Dos2unix can only detect if a file is in UTF-16 format if the file has a BOM. When an
UTF-16 file doesn't have a BOM, dos2unix will see the file as a binary file.
Use dos2unix in combination with iconv(1) to convert an UTF-16 file without BOM.
Dos2unix never writes a BOM in the output file, unless you use option "-m".
Unix2dos writes a BOM in the output file when the input file has a BOM, or when option
"-m" is used.
Convert from Windows UTF-16 (with BOM) to Unix UTF-8
dos2unix -n in.txt out.txt
Convert from Windows UTF-16 (without BOM) to Unix UTF-8
iconv -f UTF-16 -t UTF-8 in.txt | dos2unix > out.txt
Convert from Unix UTF-8 to Windows UTF-8 with BOM
unix2dos -m -n in.txt out.txt
Convert from Unix UTF-8 to Windows UTF-16
unix2dos < in.txt | iconv -f UTF-8 -t UTF-16 > out.txt
Read input from 'stdin' and write output to 'stdout'.
dos2unix -l -c mac
Convert and replace a.txt. Convert and replace b.txt.
dos2unix a.txt b.txt
dos2unix -o a.txt b.txt
Convert and replace a.txt in ascii conversion mode.
Convert and replace a.txt in ascii conversion mode. Convert and replace b.txt in 7bit
dos2unix a.txt -c 7bit b.txt
dos2unix -c ascii a.txt -c 7bit b.txt
dos2unix -ascii a.txt -7 b.txt
Convert a.txt from Mac to Unix format.
dos2unix -c mac a.txt
Convert a.txt from Unix to Mac format.
unix2dos -c mac a.txt
Convert and replace a.txt while keeping original date stamp.
dos2unix -k a.txt
dos2unix -k -o a.txt
Convert a.txt and write to e.txt.
dos2unix -n a.txt e.txt
Convert a.txt and write to e.txt, keep date stamp of e.txt same as a.txt.
dos2unix -k -n a.txt e.txt
Convert and replace a.txt. Convert b.txt and write to e.txt.
dos2unix a.txt -n b.txt e.txt
dos2unix -o a.txt -n b.txt e.txt
Convert c.txt and write to e.txt. Convert and replace a.txt. Convert and replace b.txt.
Convert d.txt and write to f.txt.
dos2unix -n c.txt e.txt -o a.txt b.txt -n d.txt f.txt
Use dos2unix in combination with the find(1) and xargs(1) commands to recursively convert
text files in a directory tree structure. For instance to convert all .txt files in the
directory tree under the current directory type:
find . -name *.txt |xargs dos2unix
The primary language is selected with the environment variable LANG. The LANG variable
consists out of several parts. The first part is in small letters the language code.
The second is optional and is the country code in capital letters, preceded with an
underscore. There is also an optional third part: character encoding, preceded with a
dot. A few examples for POSIX standard type shells:
export LANG=nl Dutch
export LANG=nl_NL Dutch, The Netherlands
export LANG=nl_BE Dutch, Belgium
export LANG=es_ES Spanish, Spain
export LANG=es_MX Spanish, Mexico
export LANG=en_US.iso88591 English, USA, Latin-1 encoding
export LANG=en_GB.UTF-8 English, UK, UTF-8 encoding
For a complete list of language and country codes see the gettext manual:
On Unix systems you can use to command locale(1) to get locale specific information.
With the LANGUAGE environment variable you can specify a priority list of languages,
separated by colons. Dos2unix gives preference to LANGUAGE over LANG. For instance,
first Dutch and then German: "LANGUAGE=nl:de". You have to first enable localization,
by setting LANG (or LC_ALL) to a value other than "C", before you can use a language
priority list through the LANGUAGE variable. See also the gettext manual:
If you select a language which is not available you will get the standard English
With the environment variable DOS2UNIX_LOCALEDIR the LOCALEDIR set during compilation
can be overruled. LOCALEDIR is used to find the language files. The GNU default value
is "/usr/local/share/locale". Option --version will display the LOCALEDIR that is
Example (POSIX shell):
On success, zero is returned. When a system error occurs the last system error will be
returned. For other errors 1 is returned.
The return value is always zero in quiet mode, except when wrong command-line options are
Benjamin Lin - <email@example.com> Bernd Johannes Wuebben (mac2unix mode) -
<firstname.lastname@example.org>, Christian Wurll (add extra newline) - <email@example.com>, Erwin
Waterlander - <firstname.lastname@example.org> (Maintainer)
Project page: <http://waterlan.home.xs4all.nl/dos2unix.html>
SourceForge page: <http://sourceforge.net/projects/dos2unix/>
file(1) find(1) iconv(1) locale(1) xargs(1)
dos2unix 2012-09-15 dos2unix(1)