                RAR - What's new in the latest version


   Version 6.12

   1. Security vulnerability allowing to create unpacked files outside
      of destination directory is fixed. This issue exists in Unix RAR only
      and doesn't affect WinRAR and Android RAR.

      We are thankful to Simon Scannell from SonarSource for reporting it.


   Version 6.11

   1. Switch -mes can be also used to suppress the password prompt
      and abort when adding files to encrypted solid archive.

   2. Additional measures to prevent extracting insecure links are
      implemented.

   
   Version 6.10
   
   1. Switch -si can be used when extracting or testing to read archive
      data from stdin, such as: 

        cat docs.rar | rar x -si -o+ -pmypwd dummy docs/

      Even though the archive name is ignored with this switch,
      an arbitrary dummy archive name has to specified in the command line.
            
      Operations requiring backward seeks are unavailable in this mode.
      It includes displaying archive comments, testing the recovery record,
      utilizing the quick open information, processing multivolume archives.

      Prompts requiring user interaction are not allowed.
      Use -o[+|-|r], -p<pwd> or -mes switches to suppress such prompts.
   
   2. New -ep4<path> switch excludes the path prefix when archiving
      or extracting if this path is found in the beginning of archived name.
      Path is compared with names already prepared to store in archive,
      without drive letters and leading path separators. For example:

        rar a -ep4texts/books archive /texts/books/technical

      removes "text/books" from archived names, so they start
      from 'technical'.
   
   3. New -mes switch skips encrypted files when extracting or testing.
      It replaces former -p- switch.

   4. New -op<path> switch sets the destination directory for 'x' and 'e'
      extraction commands. Unlike <path_to_extract/> command line parameter,
      this switch also accepts paths without trailing path separator
      character.

   5. If 'p' command is used to print a file to stdout, informational
      messages are suppressed automatically to prevent them mixing
      with file data.

   6. "Generate archive name by mask" option and switch -ag treat only
      first two 'M' characters after 'H' as minutes. Previously any
      amount of such characters was considered as minutes.

      It makes possible to place the time field before the date,
      like -agHHMM-DDMMYY. Previous versions considered all 'M'
      in this string as minutes.

   7. Maximum allowed size of RAR5 recovery record is increased to 1000%
      of protected data size. Maximum number of RAR5 recovery volumes
      can be 10 times larger than protected RAR volumes.

      Previous WinRAR versions are not able to use the recovery record
      to repair broken archives if recovery record size exceeds 99%.
      Similarly, previous versions cannot use recovery volumes
      if their number is equal or larger than number of RAR volumes.

   8. Warning is issued if entered password exceeds the allowed limit
      of 127 characters and is truncated. Previously such passwords
      had been truncated silently.

   9. Command line -en switch is not supported anymore.
      It created RAR4 archives without the end of archive record.

      End of archive record permits to gracefully skip external data
      like digital signatures.

  10. Bugs fixed:

      1) the total progress could be displayed incorrectly when using
         -oi, -f, -u switches or appropriate GUI options.

   
   Version 6.02

   1. Switch -idn hides archived names also in 'v' and 'l' commands.
      It can be useful if only the archive type or total information
      is needed.
   
   2. Bugs fixed:

      a) after archiving data including a lot of directories,
         Unix RAR could display less than 100% total progress percent,
         even though it added all specified files and directories to archive.

   
   Version 6.01

   1. If -idn switch is used together with -t or -df in console RAR
      when archiving, it additionally disables "Deleting <filename>"
      or "Testing <filename>" messages, normally issued by these switches.

      Also -idn disables directory creation messages when extracting
      a file to non-existing directory.

   
   Version 6.00

   1. "Ignore" and "Ignore All" options are added to read error prompt.
      "Ignore" allows to continue processing with already read file part
      only and "Ignore All" does it for all future read errors.

      For example, if you archive a file, which portion is locked by another
      process, and if "Ignore" is selected in read error prompt,
      only a part of file preceding the unreadable region will be saved
      into archive.

      It can help to avoid interrupting lengthy archiving operations,
      though be aware that files archived with "Ignore" are incomplete.
      
      If switch -y is specified, "Ignore" is applied to all files by default.

      Previosuly available "Retry" and "Quit" options are still present
      in read error prompt as well.

   2. Exit code 12 is returned in case of read errors. This code is returned
      for all options in the read error prompt, including a newly introduced
      "Ignore" option.

      Previously more common fatal error code 2 was returned for read errors.

   3. New -ad2 switch places extracted files directly to archive's own folder.
      Unlike -ad1, it does not create a separate subfolder for each unpacked
      archive.

   4. When unpacking a part of files from solid volume set, RAR attempts to
      skip volumes in the beginning and start extraction from volume closest
      to specified file and with reset solid statistics.

      By default RAR resets the solid statistics in the beginning
      of large enough solid volumes where possible. For such volumes
      extracting a part of files from the middle of volume set can be
      faster now.

      It does not affect performance when all archived files are unpacked.

   5. Previously RAR automatically resorted to extracting from first volume,
      when user started extraction from non-first volume and first volume
      was available. Now RAR does so only if all volumes between first
      and specified are also available.

   6. Switch -idn hides archived names output in archiving, extraction
      and some other commands. Other messages and total percentage
      are not affected.

      You can use this switch to reduce visual clutter and console output
      overhead when archiving or extracting a lot of small files.

      Minor visual artifacts, such as percentage indicator overwriting
      few last characters of error messages, are possible with -idn.

   7. Switch -mci is removed. Optimized compression of Itanium executables
      is not supported anymore. RAR still can decompress already existing
      archives utilizing Itanium executable compression.

   
   Version 5.91

   1. Bugs fixed:

      a) Unix RAR failed to properly unpack files from subfolders of
         archives created by RAR 1.40.

   
   Version 5.90
   
   1. RAR compression speed is improved for CPUs with 16 and more cores.

   2. "Fastest" method (-m1 command line equivalent) typically achieves
      a higher compression ratio for highly compressible data types
      when creating RAR5 archives.

   3. Maximum number of utilized threads is increased from 32 to 64.
      Command line -mt<threads> switch accepts values from 1 to 64.
         
   4. "Repair" performance for RAR5 archives with recovery record
      and without data shifts is improved. It deteriorated in RAR 5.80
      and is now restored to original level.

   5. Password prompt is not issued when performing recovery record based
      repair for RAR5 archives with encrypted file names.
      This command can be performed without providing a password.

   6. Bugs fixed:

      a) "Repair" command could erroneously display "Recovery record is
         corrupt" message when processing an archive with valid recovery
         record. This message did not prevent further repair operation.

   
   Version 5.80
   
   1. It is allowed to combine several modifiers in the same -ts switch.
      For example, we can use -tsca instead -tsc -tsa.

   2. Command line -agf<default_format> switch specifies the default format
      string for -ag switch. It has a practical value only if placed to
      rar.ini configuration file or to RAR environment variable.
      For example, if we set RAR environment variable to -agfYYYY-MMM-DD,
      we can use -ag without a parameter with YYYY-MMM-DD format string
      assumed.

   3. Switches -ed and -e+d can be used in archive processing commands
      for any combination of RAR and archive operating systems.
      In older versions RAR for Windows could not use them for Unix RAR
      archives also as RAR for Unix for Windows RAR archives.

   4. Similarly to RAR5 volumes, recovery volumes in RAR4 format use
      the same width of volume number field as corresponding RAR volumes.
      While previously RAR could create arc.part01.rar and arc.part1.rev
      in RAR4 format, now both types of volumes will use "part01".

   5. "Find string in archives" "i" command:

      a) if "t" modifer is used, additionally to already supported
         ANSI, OEM and UTF-16 encodings RAR will search the specified string
         in UTF-8 files as well;
      
      b) better performance, especially for case insensitive search;

      c) hexadecimal search output includes both text and hexadecimal
         representation of found matches.

   6. Bugs fixed:

      a) previous RAR version failed to unpack folder records
         in archives created by RAR 1.50.
      

   Version 5.71
   
   1. Ctrl+C allows to abort RAR "l" command quickly. In previous versions
      it could take several seconds until list command stopped.

   2. Bugs fixed:

      a) in "RAR x -x<mask> arcname" command, parent directories of files
         matching the specified mask also were excluded from extracting.

   
   Version 5.70

   1. Command line -ta, -tb, -tn, -to switches accept 'm', 'c' and 'a'
      modifiers after the switch name. So file time conditions can include
      not only the file modification time as in previous versions,
      but also creation (ctime "change time" for Unix) and last access time.

      Such switch can include multiple modifiers to set the same date
      for all specified times. For example, -tamc20190215 will process files
      modified and created after 2019-02-15. 
      
      New 'o' modifier permits to switch from AND to OR logic,
      so -tamco20190215 includes files modified or created after 2019-02-15.
      It is also allowed to specify several time filtering switches
      with different dates in the same command line, like:
      -taco20190201 -tbmo20190210

      Switches -ta and -tn also include files matching the specified date
      exactly. Switches -tb and -to exclude such files.

   2. New -ad1 switch can be used when unpacking multiple archives
      recursively, such as 'rar x -r -ad1 arc\*.rar'. It creates
      a separate folder for files unpacked from each archive,
      but unlike already existing -ad switch, it creates such folders
      in each archive folder.

   3. Bugs fixed:

      a) RAR mixed up source and destination file sizes and times
         in the overwrite prompt when updating a file in RAR archive
         with -o switch;

      b) commands modifying an existing RAR4 volume reset the volume number
         field to 1. While it did not affect extraction, tools like WinRAR
         displayed a wrong volume number for such volumes;

      c) fixed a crash when reading an archive comment from a corrupt
         RAR file.


   Version 5.61

   1. Fixed a crash when processing corrupt RAR archives.
      This issue may be also associated with security risks.

   
   Version 5.60

   1. "Repair" command efficiency is improved for recovery record protected
      RAR5 archives. Now it can detect deletions and insertions of unlimited
      size also as shuffled data including data taken from several recovery
      record protected archives and merged into a single file in arbitrary
      order.

   2. If encoding of comment file specified in -z<file> switch is not
      defined with -sc switch, RAR attempts to detect UTF-8, UTF-16LE
      and UTF-16BE encodings based on the byte order mask and data
      validity tests.

   3. "Update" and "Fresh" commands ('u' and 'f' in the command line mode)
      quit immediately if no files are to be updated. Previously they created
      a temporary archive before quitting when updating archives with recovery
      record or quick open information.

   4. "Repair" command issues "Recovery record is corrupt" message
      after repairing RAR5 archive containing a broken recovery record.
      Previously such message was issued only by "Test" command
      and "Repair" handled most of recovery record damages silently.

   5. Bugs fixed:

      a) fixed potential security issues when processing corrupt
         RAR archives;

      b) -tl and -tk switches did not work with archive modification
         commands;

      c) command like 'rar a arcname.rar subdir/arcname.rar' erroneously
         issued "No files" warning and refused to add the file.


   Version 5.50

   1. RAR uses RAR 5.0 archive format by default. You can change it to
      RAR 4.x compatible format with -ma4 command line switch.

   2. Added support for 1 nanosecond file time precision on Unix platform.

   3. You can specify 'f' charset value in -sc switch to use UTF-8
      encoding. For example:

      rar a -scfl arcname @filelist.txt

      to read contents of filelist.txt as UTF-8 text.

   4. RAR "lt" and "vt" commands display file times with nanosecond
      precision. Such precision is used in RAR5 archives created
      by RAR/Unix 5.50. Archives created by Windows RAR version
      have 100ns file time precision.

   5. Only '+', '-' and '1' precision modifiers are supported
      in -ts switch now. Use '+' to store the file time with maximum
      precision, '-' to omit the file time and '1' to store it with
      1 second precision. Intermediate precision modes previously
      defined with '2' and '3' modifiers are not available in RAR 5.0
      archive format and ignored by -ts switch.

   6. If a wrong password is entered when unpacking an encrypted file
      in RAR5 archive, RAR proposes to enter a valid password
      for same file again instead of aborting extraction.

   7. Bugs fixed:

      a) fixed crashes and security vulnerability when unpacking corrupt
         RAR archives;

      b) directory owners were not set when extracting RAR5 archives
         created with -ow switch;

      c) if only creation or only last access file time was stored in RAR5
         archive with 1 second precision, such as with -ma5 -tsm- -tsa1
         switches, this stored time was ignored when extracting.


   Version 5.40

   1. If RAR recovery volumes (.rev files) are present in the same directory
      as usual RAR volumes, archive test command verifies .rev contents
      after completing testing .rar files.

      If you wish to test only .rev files without checking .rar volumes,
      you can run:

      rar t arcname.part1.rev

   2. Previously "Synchronize archive contents" mode (-as switch) aborted
      if some of archiving directories could not be read. Now RAR continues
      performing the operation and preserves archived files matching
      unreadable directories.

   3. If -iver switch is specified, RAR displays the version number
      and quits. You can run just "RAR -iver".
   
   4. If -p switch is used without optional <pwd> parameter,
      a password can be also set with file redirection or pipe.

      For example: rar -p myarc.rar myfiles < psw.txt

   5. RAR treats 'arcname.partN' as 'arcname.partN.rar'
      if 'arcname.partN' does not exist and 'arcname.part#.rar' exists.

      For example, it is allowed to run:

      RAR x arcname.part01

      to start extraction from arcname.part01.rar

   6. Maximum comment length for RAR archives is increased
      from 64 to 256 KB.

   7. Switch -scul can be used to process big endian UTF-16 list files
      as well, provided that they have a correct byte order mark.
      Previously it allowed only little endian file lists.



   Version 5.30

   1. Directory wildcards are allowed in RAR command line in file names to
      archive. For example:

      rar a backup c:\backup\2015*\*

      Recursion is enabled automatically for such directory wildcards
      even if -r switch is not specified.

   2. New 'R' object for -sc switch defines encoding of console
      RAR messages sent to redirected files and pipes. For example:

      rar lb -scur data > list.txt

      will produce Unicode list.txt with archived file names.

   3. Console RAR "l" and "v" commands display file time in YYYY-MM-DD
      format.

   4. "Test" command also verifies contents of NTFS alternate data streams
      in RAR 3.x - 5.x archives. Previously their contents was checked
      only during extraction command.

   5. Bugs fixed:

      a) console RAR crashed instead of displaying an overwrite prompt
         when attempting to add files to already existing volumes;

      b) console RAR "lt" command did not display seconds in file timestamp.

   
   Version 5.21

   1. While previous versions could produce RAR5 volumes of slightly
      smaller than requested size sometimes, such situation is less
      likely now. In most cases volume size equals to specified by user.

   2. Now by default RAR skips symbolic links with absolute paths
      in link target when extracting. You can enable creating such links
      with -ola switch.

      Such links pointing to directories outside of extraction destination
      directory can present a security risk. Enable their extraction only
      if you are sure that archive contents is safe, such as your own backup.

   
   Version 5.20

   1. RAR can read the default set of switches from .rarrc file stored
      in the user's home directory. Previously it was possible to
      define only the same set of switches for all RAR command with
      "switches=<switches>" string. Now .rarrc also allows to specify
      separate switch sets for individual RAR commands using
      the following syntax:

      switches_<command>=<any RAR switches, separated by spaces>

      For example:

      switches_a=-m5 -s
      switches_x=-o+

   2. File overwrite prompt displays the size and modification time
      for existing and new files.

   3. When archiving from stdin with -si switch, RAR sets the current system
      time to modification time of archived file. Previous version did not
      set this time at all.

   4. It is possible to use -si and -v<size> switches together. Previous
      versions did not allow to create volumes when archiving from stdin.

   
   Version 5.11

   1. Timestamp is set to extracted symlinks.

   2. Bugs fixed:

      a) deleting a file in RAR5 solid archive containing files stored
         with -ver switch caused such files to lose version information.

   
   Version 5.10

   1. Switch -ai can be used when creating RAR archive,
      so predefined values, typical for file and directory,
      are stored instead of actual attributes.
      Previously this switch could be used only when extracting.

   
   Version 5.00

   1. New RAR 5.0 archiving format. You can use -ma command line switch
      to create RAR 5.0 archives. By default RAR creates archives
      in 4.x format.

   2. Changes in RAR 5.0 compression algorithm:

      a) maximum compression dictionary size is increased up to 1 GB
         in 64 bit RAR. 32 bit RAR version can use up to 256 MB
         dictionary when creating an archive. Both 32 bit and 64 bit
         versions can unpack archives with any dictionary size,
         including 1 GB;

      b) default dictionary size for RAR 5.0 is 32 MB, typically resulting
         in higher compression ratio and lower speed than RAR 4.x 4 MB.
         You can use -md<size> switch to change this value;

      c) -md<size> switch syntax is modified to support larger dictionary
         sizes. Append 'k', 'm' and 'g' modifiers to specify the size
         in kilo-, mega- and gigabytes, like -md64m for 64 MB dictionary.
         If modifiers are not present, megabytes are assumed,
         so -md64m is equal to -md64;

      d) RAR 5.0 format includes Intel IA-32 executable and delta
         compression algorithms, but RAR 4.x text, audio, true color
         and Itanium algorithms are not supported. These excluded algorithms
         are not efficient for modern data types and hardware configurations;

      e) RAR 5.0 decompression can utilize several CPU cores.
         Though not to same extent as in compression algorithm,
         it improves the decompression speed on large files
         with poorly compressible data or when using BLAKE2 checksums.

   3. Changes in RAR 5.0 archive format:

      a) file times are stored as Coordinated Universal Time (UTC)
         instead of former local time, making file exchange among
         several time zones more straightforward;

      b) file names and archive comments use UTF-8 encoding.
   
   4. RAR 5.0 recovery record is based on Reed-Solomon error correction
      codes. If recovery record size is large enough, 5% and more,
      the new error correction scheme provides much higher resistance to
      multiple damages comparing to RAR 4.x recovery record.
      Smaller record, such as 1 - 2%, or less random damage type would
      result in less difference between 4.x and 5.0. For single continuous
      damage 4.x and 5.0 efficiency is about the same.

      Additionally to usual data erasures, the new recovery record
      is able to detect deletions and insertions of much larger size
      than in previous RAR versions. Maximum insertion size is several
      megabytes. Maximum deletion size depends on the damage type
      and in some cases can be as large as the recovery record size.
      
      Still, the best recovery performance and efficiency is achieved
      if no deletions and insertions are present, so all data including
      damaged sectors preserve their original positions. Thus, if you use
      some special software to copy an archive from damaged media,
      it is better to choose the mode, when damaged sectors are filled by
      zeroes or any other data instead of cutting them out completely
      from resulting file.

      RAR 5.0 recovery record is more resistant to damage of recovery record
      itself and can utilize a partially corrupt recovery record data.
      Note, though, that "Repair" command does not fix broken blocks
      in recovery record. Only file data are corrected. After successful
      archive repair, you may need to create a new recovery record
      for saved files.

      New recovery record is not based on 512 byte sectors anymore 
      and incorporates more complicated data structures. So it is impossible
      to specify its size in sectors. For RAR 5.0 archives the parameter of
      -rr[N] switch and rr[N] command is always treated as a percent of
      archive size regardless of presence of % character. Typically N%
      recovery record can repair up to N% of continuously damaged data
      and increases the archive size by only slightly more than N%.
      Ability to fix multiple damages is proportional to N.

      We used "Screaming Fast Galois Field Arithmetic Using Intel
      SIMD Instructions" paper by James S. Plank, Kevin M. Greenan
      and Ethan L. Miller to improve Reed-Solomon coding performance.
      Also we are grateful to Artem Drobanov and Bulat Ziganshin
      for samples and ideas allowed to make Reed-Solomon coding
      more efficient.

   5. "Test" command verifies validity of RAR 5.0 recovery record.
      Recovery record is tested after processing all archived files.

      If corrupt archive contains the recovery record, it might be possible
      to repair it even if recovery record validity test is failed.
      "Repair" command attempts to utilize even a partially damaged
      recovery record. So treat the negative recovery record test result
      as a reason to re-create the archive if original files are still
      available, but not as a reason to avoid "Repair" command.

   6. Changes in RAR 5.0 encryption algorithm:

      a) encryption algorithm is changed from AES-128 to AES-256 in CBC mode.
         Key derivation function is based on PBKDF2 using HMAC-SHA256;

      b) special password verification value allows to detect most of
         wrong passwords without necessity to unpack the entire file;

      c) if archive headers are not encrypted ("Encrypt file names" option
         is off), file checksums for encrypted RAR 5.0 files are modified
         using a special password dependent algorithm, to make impossible
         guessing file contents based on checksums. Do not expect such
         encrypted file checksums to match usual CRC32 and BLAKE2 values.
   
   7. Switch -htb allows to utilize 256 bit length BLAKE2sp hash
      ( https://blake2.net ) instead of 32 bit CRC32 as a file checksum.

      While producing slightly larger archives, BLAKE2 can be used
      for file contents identification. If two files have the same
      BLAKE2 value, it practically guarantees that file contents
      is the same. BLAKE2 error detection property is also stronger
      than in much shorter CRC32.

   8. Features removed:

      a) authenticity verification feature did not provide the required
         level of reliability and was removed;
      
      b) switch -en (do not add "end of archive" block) is not supported
         by RAR 5.0 archives, which always have the end of archive block.
         This block helps RAR to safely skip external data like
         digital signatures appended to archive;

      c) old style extension based arcname.rNN volume names are not
         supported by RAR 5.0 archives, which use only arcname.partN.rar
         volume names;
      
      d) file comments are not supported anymore both in RAR 4.x
         and RAR 5.0 archives. Console RAR 'cf' command is removed.
         It does not affect the archive comment support, which is present
         in both versions of archive format and is not planned for removal.

   9. Switch -oh stores hard links as link instead of file. It is available
      only for RAR 5.0 archive format.
   
  10. Changes in recovery volume processing in RAR 5.0 archive format:

      a) maximum number of RAR+REV volumes in RAR 5.0 format is 65535
         instead of 255;

      b) recovery volume operations are faster than in RAR 4.x;

      c) additionally to recovery data, RAR 5.0 REV files also store
         service information such as checksums of protected RAR files.
         So they are slightly larger than RAR volumes which they protect.
         If you plan to copy individual RAR and REV files to some removable
         media, you need to take it into account and specify RAR volume
         size by a few kilobytes smaller than media size.
  
  11. Command line RAR returns the exit code 11 if it can detect that
      user entered a wrong password. This code can be returned only
      for RAR 5.0 archives. It is impossible to distinguish a wrong
      password and data damage for RAR 4.x archives.

  12. 'v' and 'l' commands display archived file names in the end of line,
      not in that beginning as before. Also some fields previously
      available in 'l' and 'v' output are now shown only by 'lt' and 'vt'.
      
      'vt' and 'lt' commands provide the detailed multiline information
      for every archived file.

      'vta' and 'lta' also include service headers into list.

   13. UTF-16 little endian encoding is used in RAR log file rar.log,
       so Unicode file names are stored in the log correctly.

       You can use -sc<charset>g switch to change the default log file
       encoding, such as -scag for native single byte encoding.

   14. Command line 'r' (repair) command can include an optional destpath\
       parameter defining the destination folder for repaired archive:

       rar r archive.rar destpath\
