Provided by: darcs_2.10.2-1_amd64 bug

NAME

       darcs - an advanced revision control system

SYNOPSIS

       darcs command <arguments|[options]>...

       Where the commands and their respective arguments are

       darcs help [<darcs_command> [darcs_subcommand]]
       darcs add <file|directory> ...
       darcs remove <file|directory> ...
       darcs move <source> ... <destination>
       darcs replace <old> <new> <file> ...
       darcs revert [file|directory]...
       darcs unrevert
       darcs whatsnew [file|directory]...
       darcs record [file|directory]...
       darcs unrecord
       darcs amend [file|directory]...
       darcs mark-conflicts
       darcs tag [tagname]
       darcs setpref <pref> <value>
       darcs diff [file|directory]...
       darcs log [file|directory]...
       darcs annotate [file|directory]...
       darcs dist
       darcs test [[initialization] command]
       darcs show contents [file]...
       darcs show files [file|directory]...
       darcs show index
       darcs show pristine
       darcs show repo
       darcs show authors
       darcs show tags
       darcs show patch-index-all
       darcs show patch-index-files
       darcs show patch-index-status
       darcs show patch-index-test
       darcs pull [repository]...
       darcs fetch [repository]...
       darcs obliterate
       darcs rollback [file|directory]...
       darcs push [repository]
       darcs send [repository]
       darcs apply <patchfile>
       darcs clone <repository> [<directory>]
       darcs initialize [<directory>]
       darcs optimize clean
       darcs optimize http
       darcs optimize reorder
       darcs optimize enable-patch-index
       darcs optimize disable-patch-index
       darcs optimize compress
       darcs optimize uncompress
       darcs optimize relink
       darcs optimize pristine
       darcs optimize upgrade
       darcs optimize cache <directory> ...
       darcs repair
       darcs convert darcs-2 <source> [<destination>]
       darcs convert export
       darcs convert import [<directory>]
       darcs rebase pull [repository]...
       darcs rebase apply <patchfile>
       darcs rebase suspend
       darcs rebase unsuspend
       darcs rebase obliterate
       darcs rebase log

DESCRIPTION

       Darcs is a free, open source revision control system. It is:

       ·  Distributed: Every user has access to the full command set, removing boundaries between
          server and client or committer and non‐committers.

       ·  Interactive: Darcs is easy to learn and efficient to use because it asks you  questions
          in response to simple commands, giving you choices in your work flow. You can choose to
          record one change in a file, while ignoring another. As you update from  upstream,  you
          can review each patch name, even the full `diff' for interesting patches.

       ·  Smart:  Originally  developed  by  physicist  David  Roundy, darcs is based on a unique
          algebra of patches.  This smartness lets you respond to changing demands in  ways  that
          would otherwise not be possible. Learn more about spontaneous branches with darcs.

OPTIONS

       Different options are accepted by different Darcs commands.  Each command's most important
       options are listed in the COMMANDS section.  For a full list of all options accepted by  a
       particular command, run `darcs command --help'.

   Selecting Patches:
       The  --patches option yields patches with names matching an *extended* regular expression.
       See regex(7) for details.  The --matches  option  yields  patches  that  match  a  logical
       (Boolean) expression: one or more primitive expressions combined by grouping (parentheses)
       and the complement (not),  conjunction  (and)  and  disjunction  (or)  operators.   The  C
       notation for logic operators (!, && and ||) can also be used.

       -  --patches=regex  is a synonym for --matches='name regex' - --hash=HASH is a synonym for
       --matches='hash HASH' - --from-patch and --to-patch are synonyms for --from-match='name...
       and --to-match='name...  - --from-patch and --to-match can be unproblematically combined:
         `darcs changes --from-patch='html.*documentation' --to-match='date 20040212'`

       The following primitive Boolean expressions are supported:

       -  exact  -  check  a  literal  string  against  the patch name.  - name - check a regular
       expression against the patch name.  - author - check  a  regular  expression  against  the
       author name.  - hunk - check a regular expression against the contents of a hunk patch.  -
       comment - check a regular expression against the log message.  - hash - match a full  hash
       or a prefix for a patch.  - date - match the patch date.  - touch - match file paths for a
       patch.

       Here are some examples:

           darcs  annotate  --summary  --match  'exact  "Resolve  issue17:  use  dynamic   memory
       allocation."'
           darcs annotate --summary --match 'name issue17'
           darcs annotate --summary --match 'name "^[Rr]esolve issue17\>"'
           darcs annotate --summary --match 'author "David Roundy"'
           darcs annotate --summary --match 'author droundy'
           darcs annotate --summary --match 'author droundy@darcs.net'
           darcs annotate --summary --match 'hunk "foo = 2"'
           darcs annotate --summary --match 'hunk "^instance .* Foo where$"'
           darcs annotate --summary --match 'comment "prevent deadlocks"'
           darcs annotate --summary --match 'hash c719567e92c3b0ab9eddd5290b705712b8b918ef'
           darcs annotate --summary --match 'hash c7195'
           darcs annotate --summary --match 'date "2006-04-02 22:41"'
           darcs annotate --summary --match 'date "tea time yesterday"'
           darcs annotate --summary --match 'touch src/foo.c'
           darcs annotate --summary --match 'touch src/'
           darcs annotate --summary --match 'touch "src/*.(c|h)"'

COMMANDS

       darcs help [<darcs_command> [darcs_subcommand]]
           Without  arguments,  `darcs  help`  prints  a categorized list of darcs commands and a
           short description of each one.  With  an  extra  argument,  `darcs  help  foo`  prints
           detailed help about the darcs command foo.

   Changing and querying the working copy:
       darcs add <file|directory> ...
           Generally  a repository contains both files that should be version controlled (such as
           source code) and files that Darcs should ignore (such as executables compiled from the
           source  code).   The  `darcs add` command is used to tell Darcs which files to version
           control.

           When an existing project is first imported into a Darcs repository, it  is  common  to
           run `darcs add -r *` or `darcs record -l` to add all initial source files into darcs.

           Adding symbolic links (symlinks) is not supported.

           Darcs  will  ignore  all  files and folders that look "boring".  The `--boring` option
           overrides this behaviour.

           Darcs will not add file if another file in the same folder has the same  name,  except
           for  case.  The `--case-ok` option overrides this behaviour.  Windows and OS X usually
           use filesystems that do not allow files a folder to have the same name except for case
           (for example, `ReadMe` and `README`).  If `--case-ok` is used, the repository might be
           unusable on those systems!

       darcs remove <file|directory> ...
           The `darcs remove` command exists primarily for symmetry  with  `darcs  add`,  as  the
           normal  way  to  remove  a  file  from version control is simply to delete it from the
           working tree.  This command is only useful in the unusual  case  where  one  wants  to
           record  a  removal  patch  WITHOUT deleting the copy in the working tree (which can be
           re-added).

           Note that applying a removal patch to a repository (e.g. by pulling  the  patch)  will
           ALWAYS affect the working tree of that repository.

       darcs move <source> ... <destination>
           Darcs  cannot  reliably  distinguish between a file being deleted and a new one added,
           and a file being moved.  Therefore Darcs always assumes the former, and  provides  the
           `darcs mv` command to let Darcs know when you want the latter.  This command will also
           move the file in the working tree (unlike `darcs remove`), unless it has already  been
           moved.

           Darcs  will  not  rename  a file if another file in the same folder has the same name,
           except for case.  The `--case-ok` option overrides this behaviour.  Windows and  OS  X
           usually  use filesystems that do not allow files a folder to have the same name except
           for case (for example, `ReadMe` and `README`).  If `--case-ok` is used, the repository
           might be unusable on those systems!

       darcs replace <old> <new> <file> ...
           In  addition  to  line-based  patches,  Darcs  supports  a  limited  form  of  lexical
           substitution.  Files are treated as sequences of words, and each occurrence of the old
           word is replaced by the new word.  This is intended to provide a clean way to rename a
           function or variable.  Such renamings typically affect lines all  through  the  source
           code,  so  a  traditional line-based patch would be very likely to conflict with other
           branches, requiring manual merging.

           Files are tokenized according to one simple rule: words are  strings  of  valid  token
           characters, and everything between them (punctuation and whitespace) is discarded.  By
           default, valid  token  characters  are  letters,  numbers  and  the  underscore  (i.e.
           `[A-Za-z0-9_]`).   However  if  the  old  and/or new token contains either a hyphen or
           period, BOTH hyphen and period are treated as valid (i.e. `[A-Za-z0-9_.-]`).

           The set of valid characters can be customized using the `--token-chars`  option.   The
           argument  must  be  surrounded  by  square  brackets.   If a hyphen occurs between two
           characters in the set, it is treated as a set range.  For  example,  in  most  locales
           `[A-Z]`  denotes  all  uppercase  letters.   If  the first character is a caret, valid
           tokens are taken to be the complement  of  the  remaining  characters.   For  example,
           `[^:\n]`  could be used to match fields in the passwd(5), where records and fields are
           separated by newlines and colons respectively.

           If  you  choose  to  use  `--token-chars`,  you  are  STRONGLY  encouraged  to  do  so
           consistently.   The  consequences  of  using  multiple  replace patches with different
           `--token-chars` arguments on the same file are not well tested nor well understood.

           By default Darcs will refuse to perform a replacement if the new token is  already  in
           use,  because  the  replacements  would  be  not  be distinguishable from the existing
           tokens.  This behaviour can be overridden by supplying the `--force`  option,  but  an
           attempt to `darcs rollback` the resulting patch will affect these existing tokens.

           Limitations:

           The  tokenizer treats files as byte strings, so it is not possible for `--token-chars`
           to include multi-byte characters, such as the non-ASCII parts  of  UTF-8.   Similarly,
           trying  to  replace a "high-bit" character from a unibyte encoding will also result in
           replacement of the same byte in files with different encodings.  For example, an acute
           a from ISO 8859-1 will also match an alpha from ISO 8859-7.

           Due  to limitations in the patch file format, `--token-chars` arguments cannot contain
           literal whitespace.  For example, `[^ \n\t]` cannot be used to declare all  characters
           except  the  space,  tab  and  newline  as  valid within a word, because it contains a
           literal space.

           Unlike POSIX regex(7) bracket expressions, character classes (such  as  `[[:alnum:]]`)
           are  NOT supported by `--token-chars`, and will be silently treated as a simple set of
           characters.

       darcs revert [file|directory]...
           The `darcs revert` command discards unrecorded changes  the  working  tree.   As  with
           `darcs record`, you will be asked which hunks (changes) to revert.  The `--all` switch
           can be used to avoid such prompting. If files  or  directories  are  specified,  other
           parts of the working tree are not reverted.

           In  you accidentally reverted something you wanted to keep (for example, typing `darcs
           rev -a` instead of `darcs rec -a`),  you  can  immediately  run  `darcs  unrevert`  to
           restore  it.   This is only guaranteed to work if the repository has not changed since
           `darcs revert` ran.

       darcs unrevert
           Unrevert is a rescue command in case you accidentally reverted something you wanted to
           keep (for example, typing `darcs rev -a` instead of `darcs rec -a`).

           This  command  may  fail  if  the  repository has changed since the revert took place.
           Darcs will ask for confirmation before executing  an  interactive  command  that  will
           DEFINITELY prevent unreversion.

       darcs whatsnew [file|directory]...
           The  `darcs  whatsnew`  command  lists unrecorded changes to the working tree.  If you
           specify a set of files and directories, only unrecorded changes  to  those  files  and
           directories are listed.

           With  the  `--summary`  option,  the  changes are condensed to one line per file, with
           mnemonics to indicate the nature and extent  of  the  change.   The  `--look-for-adds`
           option  causes  candidates  for  `darcs  add`  to  be  included in the summary output.
           Summary mnemonics are as follows:

           * `A f` and `A d/` respectively mean an added file or directory.  * `R f` and  `R  d/`
           respectively  mean  a  removed  file  or directory.  * `M f -N +M rP` means a modified
           file, with `N` lines deleted, `M`
             lines added, and `P` lexical replacements.  *  `f  ->  g`  means  a  moved  file  or
           directory.  * `a f` and `a d/` respectively mean a new, but unadded, file or
             directory, when using `--look-for-adds`.

             An exclamation mark (!) as in `R! foo.c`, means the hunk is known to
             conflict with a hunk in another patch.  The phrase `duplicated`
             means the hunk is known to be identical to a hunk in another patch.

           By  default,  `darcs  whatsnew`  uses Darcs' internal format for changes.  To see some
           context (unchanged lines) around each change, use the  `--unified`  option.   To  view
           changes  in  conventional  `diff`  format, use the `darcs diff` command; but note that
           `darcs whatsnew` is faster.

           This command exits unsuccessfully (returns a non-zero exit status)  if  there  are  no
           unrecorded changes.

   Copying changes between the working copy and the repository:
       darcs record [file|directory]...
           The `darcs record` command is used to create a patch from changes in the working tree.
           If you specify a set of files and directories, changes to other files will be skipped.

           Every patch has a name, an optional description, an author and a date.

           Darcs will launch a text editor (see `darcs help environment`) after  the  interactive
           selection,  to  let  you  enter  the patch name (first line) and the patch description
           (subsequent lines).

           The patch name should be a short sentence that concisely describes the patch, such  as
           "Add  error  handling to main event loop."  You can supply it in advance with the `-m`
           option,  in  which  case  no  text  editor   is   launched,   unless   you   use   the
           `--edit-long-comment` option.

           The  patch  description  is an optional block of free-form text.  It is used to supply
           additional information that doesn't fit in the patch  name.   For  example,  it  might
           include a rationale of WHY the change was necessary.

           A technical difference between patch name and patch description, is that matching with
           the flag `-p` is only done on patch names.

           Finally, the `--logfile` option allows you to supply a file that already contains  the
           patch name and patch description.  This is useful if a previous record failed and left
           a `darcs-record-0` file.

           Each patch is attributed to its author, usually by email address (for  example,  `Fred
           Bloggs  <fred@example.net>`).   Darcs  looks in several places for this author string:
           the `--author`  option,  the  files  `_darcs/prefs/author`  (in  the  repository)  and
           `~/.darcs/author`   (in   your   home   directory),   and  the  environment  variables
           `$DARCS_EMAIL` and `$EMAIL`.  If none of those exist, Darcs will  prompt  you  for  an
           author  string and write it to `~/.darcs/author`.  Note that if you have more than one
           email address, you can put them all in `~/.darcs/author`, one author per line.   Darcs
           will  still prompt you for an author, but it allows you to select from the list, or to
           type in an alternative.

           If you want to manually define any extra dependencies for your patch, you can use  the
           `--ask-deps`  flag,  and  darcs  will  ask  you  for  the  patch's dependencies.  Some
           dependencies may be automatically inferred from the  patch's  content  and  cannot  be
           removed.  A patch with specific dependencies can be empty.

           The  patch  date  is  generated  automatically.   It  can only be spoofed by using the
           `--pipe` option.

           If you run record with the `--pipe` option, you will be prompted for the  patch  date,
           author,  and  the  long comment. The long comment will extend until the end of file or
           stdin is reached (ctrl-D on Unixy systems, ctrl-Z on systems running a Microsoft OS).

           This interface is intended for scripting darcs, in particular for  writing  repository
           conversion  scripts.  The prompts are intended mostly as a useful guide (since scripts
           won't need them), to help you understand the format in which  to  provide  the  input.
           Here's an example of what the `--pipe` prompts look like:

               What is the date? Mon Nov 15 13:38:01 EST 2004
               Who is the author? David Roundy
               What is the log? One or more comment lines

           If  a test command has been defined with `darcs setpref`, attempting to record a patch
           will cause the test command to be run in a clean copy of the working  tree  (that  is,
           including only recorded changes).  If the test fails, you will be offered to abort the
           record operation.

           The `--set-scripts-executable` option causes scripts to  be  made  executable  in  the
           clean  copy  of the working tree, prior to running the test.  See `darcs clone` for an
           explanation of the script heuristic.

           If your test command is tediously slow (e.g. `make all`) and you are recording several
           patches in a row, you may wish to use `--no-test` to skip all but the final test.

           To see some context (unchanged lines) around each change, use the `--unified` option.

       darcs unrecord
           Unrecord  does the opposite of record: it deletes patches from the repository, without
           changing the working copy.  Deleting patches from the repository makes active  changes
           again  which  you  may  record  or  revert later.  Beware that you should not use this
           command if there is a possibility that another user may have already pulled the patch.

       darcs amend [file|directory]...
           Amend updates a "draft" patch with additions or improvements, resulting  in  a  single
           "finished" patch.

           By  default `amend` proposes you to record additional changes.  If instead you want to
           remove changes, use the flag `--unrecord`.

           When recording a draft patch, it is a good idea to start the name with `DRAFT:`.  When
           done,  remove it with `darcs amend --edit-long-comment`.  Alternatively, to change the
           patch name without starting an editor, use the `--name`/`-m` flag:

               darcs amend --match 'name "DRAFT: foo"' --name 'foo2'

           Like `darcs record`, if you call amend with files as arguments, you will only be asked
           about  changes  to  those  files.   So  to amend a patch to foo.c with improvements in
           bar.c, you would run:

               darcs amend --match 'touch foo.c' bar.c

           It is usually a bad idea to amend another developer's patch.  To make amend  only  ask
           about  your  own  patches  by  default,  you can add something like `amend match David
           Roundy` to `~/.darcs/defaults`, where `David Roundy` is your name.

       darcs mark-conflicts
           Darcs requires human guidance to unify changes to the same  part  of  a  source  file.
           When a conflict first occurs, darcs will add the initial state and both choices to the
           working tree, delimited by the markers `v v v`, `=====`,  `* * *`  and  `^  ^  ^`,  as
           follows:

               v v v v v v v
               Initial state.
               =============
               First choice.
               *************
               Second choice.
               ^ ^ ^ ^ ^ ^ ^

           However,  you might revert or manually delete these markers without actually resolving
           the conflict.  In this case, `darcs mark-conflicts` is useful to show  where  are  the
           unresolved   conflicts.    It   is  also  useful  if  `darcs  apply`  is  called  with
           `--apply-conflicts`, where conflicts aren't marked initially.

           Unless you use the `--dry-run` flag, any unrecorded changes to the working  tree  WILL
           be  lost  forever  when  you  run this command!  You will be prompted for confirmation
           before this takes place.

   Direct modification of the repository:
       darcs tag [tagname]
           The `darcs tag` command names the current repository state, so that it can  easily  be
           referred to later.  Every *important* state should be tagged; in particular it is good
           practice to tag each stable release with a number  or  codename.   Advice  on  release
           numbering can be found at <http://producingoss.com/en/development-cycle.html>.

           To reproduce the state of a repository `R` as at tag `t`, use the command `darcs clone
           --tag t R`.  The command `darcs show tags` lists all tags in the current repository.

           Tagging also provides significant performance benefits: when Darcs  reaches  a  shared
           tag that depends on all antecedent patches, it can simply stop processing.

           Like  normal  patches,  a  tag has a name, an author, a timestamp and an optional long
           description, but it does not change the working tree.  A tag can have any name, but it
           is generally best to pick a naming scheme and stick to it.

           By  default a tag names the entire repository state at the time the tag is created. If
           the --ask-deps option is used, the patches to include  as  part  of  the  tag  can  be
           explicitly selected.

           The  `darcs  tag`  command  accepts the `--pipe` option, which behaves as described in
           `darcs record`.

       darcs setpref <pref> <value>
           When working on project with multiple repositories and contributors, it  is  sometimes
           desirable  for  a preference to be set consistently project-wide.  This is achieved by
           treating a preference set with `darcs setpref` as an unrecorded change, which can then
           be recorded and then treated like any other patch.

           Valid preferences are:

           *  test  -- a shell command that runs regression tests * predist -- a shell command to
           run before `darcs dist' * boringfile -- the path to a version-controlled boring file *
           binariesfile -- the path to a version-controlled binaries file

           For  example,  a  project  using  GNU  autotools, with a `make test` target to perform
           regression tests, might enable Darcs' integrated regression testing with the following
           command:

               darcs setpref test 'autoconf && ./configure && make && make test'

           Note that merging is not currently implemented for preferences: if two patches attempt
           to set the same preference, the last patch applied to the repository will always  take
           precedence.   This  is  considered  a low-priority bug, because preferences are seldom
           set.

   Querying the repository:
       darcs diff [file|directory]...
           The `darcs diff` command compares two versions of the  working  tree  of  the  current
           repository.  Without options, the pristine (recorded) and unrecorded working trees are
           compared.  This is lower-level than the `darcs whatsnew` command, since it  outputs  a
           line-by-line  diff,  and  it is also slower.  As with `darcs whatsnew`, if you specify
           files or directories, changes to other files are not listed.  The command always  uses
           an external diff utility.

           With  the `--patch` option, the comparison will be made between working trees with and
           without that patch.  Patches *after* the selected patch are not present in  either  of
           the compared working trees.  The `--from-patch` and `--to-patch` options allow the set
           of patches in the `old' and `new' working trees to be specified separately.

           The associated tag and match options are also understood, e.g. `darcs diff  --from-tag
           1.0  --to-tag 1.1`.  All these options assume an ordering of the patch set, so results
           may be affected by operations such as `darcs optimize --reorder`.

           diff(1) is called with the arguments `-rN`.  The `--unified` option causes `-u` to  be
           passed  to diff(1).  An additional argument can be passed using `--diff-opts`, such as
           `--diff-opts=-ud` or `--diff-opts=-wU9`.

           The `--diff-command` option can be used to specify an  alternative  utility,  such  as
           meld  (GNOME) or opendiff (OS X).  Arguments may be included, separated by whitespace.
           The value is not interpreted by a shell, so shell  constructs  cannot  be  used.   The
           arguments  %1 and %2 MUST be included, these are substituted for the two working trees
           being compared.  If this option is used, `--diff-opts` is ignored.

       darcs log [file|directory]...
           The `darcs log` command lists the patches that constitute the current  repository  or,
           with `--repo`, a remote repository.  Without options or arguments, ALL patches will be
           listed.

           When given one or more files or directories as arguments, only  patches  which  affect
           those  files  or  directories are listed. This includes patches that happened to files
           before they were moved or renamed.

           When given a `--from-tag`, `--from-patch` or `--from-match`, only patches  since  that
           tag  or  patch  are  listed.  Similarly, the `--to-tag`, `--to-patch` and `--to-match`
           options restrict the list to older patches.

           The `--last` and `--max-count` options both limit the number of patches  listed.   The
           former  applies  BEFORE other filters, whereas the latter applies AFTER other filters.
           For example `darcs log foo.c --max-count 3` will print the  last  three  patches  that
           affect  foo.c,  whereas  `darcs  log  --last 3 foo.c` will, of the last three patches,
           print only those that affect foo.c.

           Three output formats exist.  The default is `--human-readable`.  You can  also  select
           `--context`,  which  is  the  internal  format  (as seen in patch bundles) that can be
           re-read by Darcs (e.g. `darcs clone --context`).

           Finally, there is `--xml-output`, which emits valid XML... unless a the patch metadata
           (author,  name  or  description)  contains a non-ASCII character and was recorded in a
           non-UTF8 locale.

           Note that while the `--context` flag may be used in conjunction with `--xml-output` or
           `--human-readable`,  in  neither case will darcs clone be able to read the output.  On
           the other hand, sufficient information WILL be output for  a  knowledgeable  human  to
           recreate the current state of the repository.

       darcs annotate [file|directory]...
           The  `darcs  annotate`  command  provides  two unrelated operations.  When called on a
           file, it will find the patch that last modified each line in that file.   When  called
           on  a  patch (e.g. using `--patch`), it will print the internal representation of that
           patch.

           The `--summary` option will result in a summarized patch annotation, similar to `darcs
           whatsnew`.  It has no effect on file annotations.

           By default, output is in a human-readable format.  The `--machine-readable` option can
           be used to generate output for machine postprocessing.

       darcs dist
           `darcs dist`  creates  a  compressed  archive  in  the  repository's  root  directory,
           containing the recorded state of the working tree (unrecorded changes and the `_darcs`
           directory are excluded).  The command accepts matchers to create an  archive  of  some
           past repository state, for instance `--tag`.

           By  default, the archive (and the top-level directory within the archive) has the same
           name as the repository, but this can be overridden with the `--dist-name` option.

           If a predist command is set (see `darcs setpref`), that command will  be  run  on  the
           recorded  state  prior  to archiving.  For example, autotools projects would set it to
           `autoconf && automake`.

           If `--zip` is used, matchers and the predist command are ignored.

       darcs test [[initialization] command]
           Run test on the current recorded state of the repository.  Given no arguments, it uses
           the  default  repository test (see `darcs setpref`).  Given one argument, it treats it
           as a test command.  Given two arguments, the first is an  initialization  command  and
           the  second  is the test (meaning the exit code of the first command is not taken into
           account to determine success of the test).  If  given  the  `--linear`  or  `--bisect`
           flags, it tries to find the most recent version in the repository which passes a test.

           `--linear`  does  linear  search  starting  from head, and moving away from head. This
           strategy is best when the test runs very quickly or the patch you're seeking  is  near
           the head.

           `--bisect`  does  binary search.  This strategy is best when the test runs very slowly
           or the patch you're seeking is likely to be in the repository's distant past.

           `--backoff` starts searching from head, skipping further and  further  into  the  past
           until  the  test  succeeds.  It then does a binary search on a subset of those skipped
           patches.  This strategy  works  well  unless  the  patch  you're  seeking  is  in  the
           repository's distant past.

           Under the assumption that failure is monotonous, `--linear` and `--bisect` produce the
           same result.  (Monotonous means that when moving  away  from  head,  the  test  result
           changes  only once from "fail" to "ok".)  If failure is not monotonous, any one of the
           patches that break the test is found at random.

       darcs show contents [file]...
           Show contents can be used to display an earlier version of some file(s).  If you  give
           show contents no version arguments, it displays the recorded version of the file(s).

       darcs show files [file|directory]...
           The  `darcs  show files` command lists those files and directories in the working tree
           that are under version control.  This command is primarily for scripting purposes; end
           users will probably want `darcs whatsnew --summary`.

           A  file is "pending" if it has been added but not recorded.  By default, pending files
           (and directories) are listed; the `--no-pending` option prevents this.

           By default `darcs show files` lists both files and directories, but the  alias  `darcs
           show  manifest`  only  lists  files.  The `--files`, `--directories`, `--no-files` and
           `--no-directories` modify this behaviour.

           By default entries are one-per-line (i.e. newline separated).  This can cause problems
           if  the  files themselves contain newlines or other control characters.  To get around
           this, the `--null` option uses the null character instead.   The  script  interpreting
           output from this command needs to understand this idiom; `xargs -0` is such a command.

           For example, to list version-controlled files by size:

               darcs show files -0 | xargs -0 ls -ldS

       darcs show index
           The  `darcs  show  index`  command  lists all version-controlled files and directories
           along with their hashes as stored in `_darcs/index`. For files, the fields  correspond
           to file size, sha256 of the current file content and the filename.
       darcs show pristine
           The  `darcs  show pristine` command lists all version-controlled files and directories
           along with the hashes of their pristine copies. For files, the  fields  correspond  to
           file size, sha256 of the pristine file content and the filename.
       darcs show repo
           The  `darcs  show  repo`  command  displays  statistics  about the current repository,
           allowing third-party scripts to access this information  without  inspecting  `_darcs`
           directly (and without breaking when the `_darcs` format changes).

           By  default,  the  number  of  patches  is  shown.   If  this  data  isn't needed, use
           `--no-files` to accelerate this command from O(n) to O(1).

           By default, output is in a human-readable format.  The `--xml-output`  option  can  be
           used to generate output for machine postprocessing.

       darcs show authors
           The  `darcs  show authors` command lists the authors of the current repository, sorted
           by the number of patches contributed.   With  the  `--verbose`  option,  this  command
           simply lists the author of each patch (without aggregation or sorting).

           An  author's  name or email address may change over time.  To tell Darcs when multiple
           author strings refer to the same individual, create an `.authorspellings` file in  the
           root  of  the  working tree.  Each line in this file begins with an author's canonical
           name and address, and may be followed by a comma separated list  of  extended  regular
           expressions.   Blank  lines  and  lines  beginning  with two hyphens are ignored.  The
           format of `.authorspelling` can be described by this pattern:

               name <address> [, regexp ]*

           There are some pitfalls concerning special characters: Whitespaces  are  stripped,  if
           you  need  space  in  regexp use [ ].  Because comma serves as a separator you have to
           escape it if you want it in regexp. Note that `.authorspelling` use  extended  regular
           expressions  so  +,  ?  and so on are metacharacters and you need to escape them to be
           interpreted literally.

           Any patch with an author string that matches the  canonical  address  or  any  of  the
           associated  regexps  is  considered  to  be  the work of that author.  All matching is
           case-insensitive and partial (it can match a substring). Use ^,$ to  match  the  whole
           string in regexps

           Currently  this  canonicalization  step  is  done only in `darcs show authors`.  Other
           commands, such as `darcs log` use author strings verbatim.

           An example `.authorspelling` file is:

               -- This is a comment.
               Fred Nurk <fred@example.com>
               John Snagge <snagge@bbc.co.uk>, John, snagge@, js@(si|mit).edu
               Chuck Jones\, Jr. <chuck@pobox.com>, cj\+user@example.com

       darcs show tags
           The tags command writes a list of all tags in the repository to standard output.

           Tab characters (ASCII character 9) in tag names  are  changed  to  spaces  for  better
           interoperability with shell tools. A warning is printed if this happens.

       darcs show patch-index-all
           The `darcs show patch-index all' command lists all information in the patch index
       darcs show patch-index-files
           The  `darcs  show patch-index files' command lists all current files registered in the
           patch index
       darcs show patch-index-status
           The `darcs show patch-index-status' reports if the patch index  is  in  sync,  out  of
           sync, or does not exist
       darcs show patch-index-test
           The `darcs show patch-index-test' tests patch index

   Copying patches between repositories with working copy update:
       darcs pull [repository]...
           Pull  is  used to bring patches made in another repository into the current repository
           (that is, either the one in the current directory,  or  the  one  specified  with  the
           `--repodir` option). Pull allows you to bring over all or some of the patches that are
           in that repository but not in this one. Pull accepts arguments, which  are  URLs  from
           which  to pull, and when called without an argument, pull will use the repository from
           which you have most recently either pushed or pulled.

           The default (`--union`) behavior is to pull  any  patches  that  are  in  any  of  the
           specified  repositories.   If  you  specify the `--intersection` flag, darcs will only
           pull those patches which are present in all source repositories.  If you  specify  the
           `--complement` flag, darcs will only pull elements in the first repository that do not
           exist in any of the remaining repositories.

           If `--reorder` is supplied, the  set  of  patches  that  exist  only  in  the  current
           repository  is brought at the top of the current history. This will work even if there
           are no new patches to pull.

           See `darcs help apply` for detailed description of many options.

       darcs fetch [repository]...
           Fetch is similar to `pull` except that it does not apply any patches  to  the  current
           repository.  Instead,  it  generates  a  patch  bundle  that  you can apply later with
           `apply`.

           Fetch's behaviour is essentially similar to pull's, so  please  consult  the  help  of
           `pull` to know more.

       darcs obliterate
           Obliterate completely removes recorded patches from your local repository. The changes
           will be undone in your working copy and the patches will not be shown in your  changes
           list anymore. Beware that you can lose precious code by obliterating!

           One  way  to  save  obliterated  patches is to use the -O flag. A patch bundle will be
           created locally, that you will be able to apply later to your repository  with  `darcs
           apply`.

       darcs rollback [file|directory]...
           Rollback  is  used to undo the effects of some changes from patches in the repository.
           The selected changes are undone in your working  copy,  but  the  repository  is  left
           unchanged. First you are offered a choice of which patches to undo, then which changes
           within the patches to undo.

           Before doing `rollback`, you may want to temporarily undo the changes of your  working
           copy (if there are) and save them for later use.  To do so, you can run `revert`, then
           run `rollback`, record a patch, and run `unrevert` to restore the saved  changes  into
           your working copy.

       darcs push [repository]
           Push  is  the  opposite  of  pull.   Push  allows you to copy patches from the current
           repository into another repository.

           If you give the `--apply-as` flag, darcs will use sudo  to  apply  the  patches  as  a
           different user.  This can be useful if you want to set up a system where several users
           can modify the same repository, but you don't want to allow them  full  write  access.
           This  isn't  secure against skilled malicious attackers, but at least can protect your
           repository from clumsy, inept or lazy users.

           Darcs push will by default compress the patch data  before  sending  it  to  a  remote
           location  via  ssh.  This  works as long as the remote darcs is not older than version
           2.5. If you get errors that indicate a corrupt patch bundle, you should try again with
           the  `--no-compress`  option  to  send  the data in un-compressed form (which is a lot
           slower for large patches, but should always work).

       darcs send [repository]
           Send is used to prepare  a  bundle  of  patches  that  can  be  applied  to  a  target
           repository.   Send  accepts  the  URL  of  the repository as an argument.  When called
           without an argument, send will use the most recent repository that was  either  pushed
           to, pulled from or sent to.  By default, the patch bundle is saved to a file, although
           you may directly send it by mail.

           The `--output`, `--output-auto-name`, and `--to` flags determine what darcs does  with
           the  patch bundle after creating it.  If you provide an `--output` argument, the patch
           bundle is saved to that file.  If you specify `--output-auto-name`, the  patch  bundle
           is  saved  to  a  file  with an automatically generated name.  If you give one or more
           `--to` arguments, the bundle of patches is sent to those locations. The locations  may
           either be email addresses or urls that the patch should be submitted to via HTTP.

           If   you  provide  the  `--mail`  flag,  darcs  will  look  at  the  contents  of  the
           `_darcs/prefs/email` file in the target repository (if it exists), and send the  patch
           by  email  to  that  address.   In this case, you may use the `--cc` option to specify
           additional recipients without overriding the default repository email address.

           If `_darcs/prefs/post` exists in the target repository, darcs will upload to  the  URL
           contained  in that file, which may either be a `mailto:` URL, or an `http://` URL.  In
           the latter case, the patch is posted to that URL.

           If there is no email address associated with the repository, darcs will prompt you for
           an email address.

           Use  the  `--subject`  flag to set the subject of the e-mail to be sent.  If you don't
           provide a subject on the command line, darcs will make one up based on  names  of  the
           patches in the patch bundle.

           Use  the  `--in-reply-to`  flag  to  set the In-Reply-To and References headers of the
           e-mail to be sent. By default no additional headers are included so e-mail will not be
           treated as reply by mail readers.

           If  you want to include a description or explanation along with the bundle of patches,
           you need to specify the `--edit-description` flag, which will cause darcs to  open  up
           an editor with which you can compose a message to go along with your patches.

           If  you  want  to  use a command different from the default one for sending email, you
           need to specify a command line with the `--sendmail-command` option. The command  line
           can  contain  some format specifiers which are replaced by the actual values. Accepted
           format specifiers are `%s` for subject, `%t` for to, `%c` for cc, `%b` for the body of
           the  mail,  `%f`  for  from,  `%a`  for  the  patch  bundle and the same specifiers in
           uppercase for the URL-encoded values.  Additionally you can add `%<` to the end of the
           command line if the command expects the complete email message on standard input. E.g.
           the command lines for evolution and msmtp look like this:

               evolution "mailto:%T?subject=%S&attach=%A&cc=%C&body=%B"
               msmtp -t %<

           Do not confuse the `--author` options with the return address that `darcs  send`  will
           set for your patch bundle.

           For example, if you have two email addresses A and B:

           * If you use `--author A` but your machine is configured to send mail from
             address  B  by default, then the return address on your message will be B.  * If you
           use `--from A` and your mail client supports setting the
             From: address arbitrarily (some non-Unix-like mail clients, especially,
             may not support this), then the return address will be A; if it does
             not support this, then the return address will  be  B.   *  If  you  supply  neither
           `--from` nor `--author` then the return
             address will be B.

           In  addition, unless you specify the sendmail command with `--sendmail-command`, darcs
           sends email using the default email command on your computer. This default command  is
           determined  by  the  `configure` script. Thus, on some non-Unix-like OSes, `--from` is
           likely to not work at all.

       darcs apply <patchfile>
           The `darcs apply` command takes a patch bundle and attempts  to  insert  it  into  the
           current  repository.  In addition to invoking it directly on bundles created by `darcs
           send`, it is used internally by `darcs push` on the remote end of an SSH connection.

           If no file is supplied, the bundle is read from standard input.

           If given an email instead of a patch bundle, Darcs will look for the bundle as a  MIME
           attachment to that email.  Currently this will fail if the MIME boundary is rewritten,
           such as in Courier and Mail.app.

           If the `--reply noreply@example.net` option is used, and the bundle is attached to  an
           email,  Darcs  will send a report (indicating success or failure) to the sender of the
           bundle (the `To` field).  The argument to noreply  is  the  address  the  report  will
           appear to originate FROM.

           The  `--cc`  option  will  cause the report to be CC'd to another address, for example
           `--cc  reports@lists.example.net,admin@lists.example.net`.    Using   `--cc`   without
           `--reply` is undefined.

           If you want to use a command different from the default one for sending mail, you need
           to specify a command line with the `--sendmail-command` option.  The command line  can
           contain  the  format  specifier  `%t`  for  to  and you can add `%<` to the end of the
           command line if the command expects the complete mail on standard input. For  example,
           the command line for msmtp looks like this:

               msmtp -t %<

           If  gpg(1)  is  installed,  you  can use `--verify pubring.gpg` to reject bundles that
           aren't signed by a key in `pubring.gpg`.

           If `--test` is supplied and a test is defined (see `darcs setpref`), the  bundle  will
           be  rejected  if  the test fails after applying it.  In that case, the rejection email
           from `--reply` will include the test output.

           A patch bundle may introduce unresolved conflicts with existing patches  or  with  the
           working   tree.    By   default,   Darcs   will   add  conflict  markers  (see  `darcs
           mark-conflicts`).

           The `--external-merge` option lets you resolve these conflicts using an external merge
           tool.   In  the  option,  `%a` is replaced with the common ancestor (merge base), `%1`
           with the first version, `%2` with the second version, and `%o`  with  the  path  where
           your  resolved  content  should  go.  For example, to use the xxdiff visual merge tool
           you'd specify: `--external-merge='xxdiff -m -O -M %o %1 %a %2'`

           The `--allow-conflicts` option will skip conflict marking; this  is  useful  when  you
           want  to  treat  a  repository  as  just a bunch of patches, such as using `darcs pull
           --union` to download of your co-workers patches before going offline.

           This can mess up unrecorded changes in the working tree, forcing you  to  resolve  the
           conflict  immediately.   To simply reject bundles that introduce unresolved conflicts,
           using the `--dont-allow-conflicts` option.  Making  this  the  default  in  push-based
           workflows is strongly recommended.

           Unlike   most   Darcs   commands,   `darcs   apply`  defaults  to  `--all`.   Use  the
           `--interactive` option to pick which patches to apply from a bundle.

       darcs clone <repository> [<directory>]
           Clone creates a copy of a  repository.   The  optional  second  argument  specifies  a
           destination  directory  for  the  new copy; if omitted, it is inferred from the source
           location.

           By default Darcs will copy every patch from the original repository.  This  means  the
           copy  is completely independent of the original; you can operate on the new repository
           even when the original is inaccessible.  If you  expect  the  original  repository  to
           remain accessible, you can use `--lazy` to avoid copying patches until they are needed
           (`copy on demand').  This is particularly useful when copying a remote repository with
           a long history that you don't care about.

           When  cloning  locally, Darcs automatically uses hard linking where possible.  As well
           as saving time and space, this enables to  move  or  delete  the  original  repository
           without  affecting  the  copy.   Hard  linking  requires  that the copy be on the same
           filesystem as the original repository, and that the filesystem support  hard  linking.
           This  includes  NTFS,  HFS+ and all general-purpose Unix filesystems (such as ext, UFS
           and ZFS). FAT does not support hard links.

           When cloning from a remote location, Darcs will look for  and  attempt  to  use  packs
           created by `darcs optimize http` in the remote repository.  Packs are single big files
           that can be downloaded instead of many little files, which makes cloning  faster  over
           HTTP.

           Darcs clone will not copy unrecorded changes to the source repository's working tree.

           You  can  copy a repository to a ssh url, in which case the new repository will always
           be complete.

           It is often desirable to make a copy of a repository that excludes some patches.   For
           example,  if  releases  are tagged then `darcs clone --tag .` would make a copy of the
           repository as at the latest release.

           An untagged repository state can still be identified unambiguously by a context  file,
           as generated by `darcs log --context`.  Given the name of such a file, the `--context`
           option will create a repository that includes only  the  patches  from  that  context.
           When  a  user  reports a bug in an unreleased version of your project, the recommended
           way to find out exactly what version they were running  is  to  have  them  include  a
           context file in the bug report.

           You  can  also make a copy of an untagged state using the `--to-patch` or `--to-match`
           options, which exclude patches  *after*  the  first  matching  patch.   Because  these
           options treat the set of patches as an ordered sequence, you may get different results
           after reordering with `darcs optimize`, so tagging is preferred.

           The `--set-scripts-executable` option causes scripts to  be  made  executable  in  the
           working tree. A script is any file that starts with a shebang ("#!").

   Administrating repositories:
       darcs initialize [<directory>]
           The  `darcs  initialize`  command turns the current directory into a Darcs repository.
           Any existing files and subdirectories become UNSAVED changes: record them with  `darcs
           record --look-for-adds`.

           This  command  creates  the `_darcs` directory, which stores version control metadata.
           It also contains per-repository settings in `_darcs/prefs/`, which you can read  about
           in the user manual.

           By default, patches of the new repository are in the darcs-2 semantics.  However it is
           possible to create a repository  in  darcs-1  semantics  with  the  flag  `--darcs-1`,
           althought  this is not recommended except for sharing patches with a project that uses
           patches in the darcs-1 semantics.

           Initialize is commonly abbreviated to `init`.

       darcs optimize clean
           This command deletes obsolete files within the repository.
       darcs optimize http
           Using this  option  creates  'repository  packs'  that  could  dramatically  speed  up
           performance  when a user does a `darcs clone` of the repository over HTTP. To make use
           of packs, the clients must have a darcs of at least version 2.10.

       darcs optimize reorder
           This command moves recent patches (those not  included  in  the  latest  tag)  to  the
           "front",  reducing  the  amount  that  a typical remote command needs to download.  It
           should also reduce the CPU time needed for some operations.
       darcs optimize enable-patch-index
           Build the patch index, an internal data structure that accelerates commands that  need
           to know what patches touch a given file. Such as annotate and log.
       darcs optimize disable-patch-index
           Delete and stop maintaining the patch index from the repository.
       darcs optimize compress
           By  default  patches  are  compressed  with  zlib  (RFC  1951)  to reduce storage (and
           download)  size.   In  exceptional  circumstances,  it  may  be  preferable  to  avoid
           compression.   In this case the `--dont-compress` option can be used (e.g. with `darcs
           record`) to avoid compression.

           The `darcs optimize uncompress` and `darcs optimize compress` commands can be used  to
           ensure  existing  patches  in  the current repository are respectively uncompressed or
           compressed.
       darcs optimize uncompress
           By default patches are  compressed  with  zlib  (RFC  1951)  to  reduce  storage  (and
           download)  size.   In  exceptional  circumstances,  it  may  be  preferable  to  avoid
           compression.  In this case the `--dont-compress` option can be used (e.g. with  `darcs
           record`) to avoid compression.

           The  `darcs optimize uncompress` and `darcs optimize compress` commands can be used to
           ensure existing patches in the current repository  are  respectively  uncompressed  or
           compressed.
       darcs optimize relink
           The `darcs optimize relink` command hard-links patches that the current repository has
           in   common   with   its   peers.    Peers   are   those   repositories   listed    in
           `_darcs/prefs/sources`,  or  defined  with  the  `--sibling` option (which can be used
           multiple times).

           Darcs uses hard-links automatically, so this command is rarely  needed.   It  is  most
           useful  if  you  used `cp -r` instead of `darcs clone` to copy a repository, or if you
           pulled the same patch from a remote repository into multiple local repositories.
       darcs optimize pristine
           This command updates the format  of  `_darcs/pristine.hashed/`,  which  was  different
           before darcs 2.3.1.
       darcs optimize upgrade
           Convert old-fashioned repositories to the current default hashed format.
       darcs optimize cache <directory> ...
           This  command  deletes  obsolete  files within the global cache.  It takes one or more
           directories as arguments, and  recursively  searches  all  repositories  within  these
           directories.  Then  it  deletes  all  files in the global cache not belonging to these
           repositories.  When no directory is given, it searches repositories in the user's home
           directory.

           It also automatically migrates the global cache to the (default) bucketed format.

       darcs repair
           The  `darcs  repair`  command  attempts  to  fix corruption in the current repository.
           Currently it can only repair  damage  to  the  pristine  tree,  which  is  where  most
           corruption occurs.  This command rebuilds a pristine tree by applying successively the
           patches in the repository to an empty tree.

           The flag `--dry-run` make this operation read-only, making darcs  exit  unsuccessfully
           (with  a  non-zero  exit status) if the rebuilt pristine is different from the current
           pristine.

       darcs convert darcs-2 <source> [<destination>]
           This command converts a repository that uses the old patch semantics  `darcs-1`  to  a
           new repository with current `darcs-2` semantics.

           WARNING:  the  repository produced by this command is not understood by Darcs 1.x, and
           patches cannot be exchanged between repositories in darcs-1 and darcs-2 formats.

           Furthermore, repositories created by different invocations of this command SHOULD  NOT
           exchange patches.

       darcs convert export
           This command enables you to export darcs repositories into git.

           For a one-time export you can use the recipe:

               $ cd repo
               $ git init ../mirror
               $ darcs convert export | (cd ../mirror && git fast-import)

           For incremental export using marksfiles:

               $ cd repo
               $ git init ../mirror
               $ touch ../mirror/git.marks
               $ darcs convert export --read-marks darcs.marks --write-marks darcs.marks
                  |     (cd     ../mirror    &&    git    fast-import    --import-marks=git.marks
           --export-marks=git.marks)

           In the case of incremental export, be  careful  to  never  amend,  delete  or  reorder
           patches in the source darcs repository.

           Also,  be  aware  that  exporting  a darcs repo to git will not be exactly faithful in
           terms of history if the darcs repository contains conflicts.

           Limitations:

           * Empty directories  are  not  supported  by  the  fast-export  protocol.   *  Unicode
           filenames are currently not correctly handled.
             See http://bugs.darcs.net/issue2359 .

       darcs convert import [<directory>]
           This  command  imports  git repositories into new darcs repositories.  Further options
           are accepted (see `darcs help init`).

           To convert a git repo to a new darcs one you may run:
               $ (cd gitrepo && git fast-export --all) | darcs convert import darcsmirror

           WARNING: git repositories with branches will produce weird results,
                    use at your own risks.

           Incremental import with marksfiles is currently not supported.

       darcs rebase pull [repository]...
           Copy and apply patches from another repository,  suspending  any  local  patches  that
           conflict.
       darcs rebase apply <patchfile>
           Apply a patch bundle, suspending any local patches that conflict.
       darcs rebase suspend
           Select patches to move into a suspended state at the end of the repo.

       darcs rebase unsuspend
           Selected patches to restore from a suspended state to the end of the repo.

       darcs rebase obliterate
           Obliterate a patch that is currently suspended.

       darcs rebase log
           List the currently suspended changes.

ENVIRONMENT

   HOME and APPDATA
       Per-user  preferences  are  set in $HOME/.darcs (on Unix) or %APPDATA%/darcs (on Windows).
       This is also the default location of the cache.

   DARCS_EDITOR, DARCSEDITOR, VISUAL and EDITOR
       To edit a patch description of email comment, Darcs will invoke an external editor.   Your
       preferred   editor  can  be  set  as  any  of  the  environment  variables  $DARCS_EDITOR,
       $DARCSEDITOR, $VISUAL or $EDITOR.  If none of these are set, editor(1) is used.

   DARCS_PAGER and PAGER
       Darcs will sometimes invoke a pager if it deems output to be too  long  to  fit  onscreen.
       Darcs  will  use  the  pager  specified  by  $DARCS_PAGER  or $PAGER.  If neither are set,
       pager(1) will be used.

   DARCS_DONT_COLOR, DARCS_ALWAYS_COLOR, DARCS_ALTERNATIVE_COLOR and DARCS_DO_COLOR_LINES
       If the terminal understands ANSI color escape  sequences,  darcs  will  highlight  certain
       keywords  and  delimiters  when  printing  patches.  This can be turned off by setting the
       environment variable DARCS_DONT_COLOR to 1. If you use a pager that happens to  understand
       ANSI colors, like `less -R`, darcs can be forced always to highlight the output by setting
       DARCS_ALWAYS_COLOR to 1. If you can't see colors you can set DARCS_ALTERNATIVE_COLOR to 1,
       and  darcs  will use ANSI codes for bold and reverse video instead of colors. In addition,
       there is an extra-colorful mode, which is not enabled by default, which can  be  activated
       with DARCS_DO_COLOR_LINES

   DARCS_DONT_ESCAPE_TRAILING_SPACES and DARCS_DONT_ESCAPE_TRAILING_CR
       By  default  darcs will escape (by highlighting if possible) any kind of spaces at the end
       of lines when showing patch contents.  If you don't want this  you  can  turn  it  off  by
       setting  DARCS_DONT_ESCAPE_TRAILING_SPACES  to  1. A special case exists for only carriage
       returns: DARCS_DONT_ESCAPE_TRAILING_CR

   DARCS_DONT_ESCAPE_ANYTHING,         DARCS_DONT_ESCAPE_ISPRINT,         DARCS_DONT_ESCAPE_8BIT,
       DARCS_DONT_ESCAPE_EXTRA and DARCS_ESCAPE_EXTRA
       Darcs  needs  to  escape  certain  characters  when printing patch contents to a terminal.
       Characters like backspace can otherwise hide  patch  content  from  the  user,  and  other
       character  sequences can even in some cases redirect commands to the shell if the terminal
       allows it.

       By default darcs will only allow printable 7-bit ASCII characters (including  space),  and
       the  two  control  characters tab and newline. All other octets are printed in quoted form
       (as `^<control letter>` or `\<hex code>`).

       Darcs has some limited support for locales.  If  the  system's  locale  is  a  single-byte
       character  encoding,  like  the  Latin  encodings,  you  can  set the environment variable
       DARCS_DONT_ESCAPE_ISPRINT to 1 and darcs will display all the printables  in  the  current
       system  locale  instead  of just the ASCII ones. NOTE: This curently does not work on some
       architectures if darcs  is  compiled  with  GHC  6.4  or  later.  Some  non-ASCII  control
       characters might be printed and can possibly spoof the terminal.

       For  multi-byte  character  encodings  things  are less smooth. UTF-8 will work if you set
       DARCS_DONT_ESCAPE_8BIT to 1, but non-printables outside  the  7-bit  ASCII  range  are  no
       longer  escaped. E.g., the extra control characters from Latin-1 might leave your terminal
       at the mercy of the patch contents. Space characters outside the 7-bit ASCII range are  no
       longer recognized and will not be properly escaped at line endings.

       As a last resort you can set DARCS_DONT_ESCAPE_ANYTHING to 1. Then everything that doesn't
       flip code sets should work, and so will all the bells and whistles in your terminal.  This
       environment  variable  can  also  be  handy  if you pipe the output to a pager or external
       filter that knows better than darcs how to handle your encoding. Note that  all  escaping,
       including  the  special  escaping  of  any  line ending spaces, will be turned off by this
       setting.

       There are two environment variables you can set to explicitly tell darcs to not escape  or
       escape  octets.  They  are  DARCS_DONT_ESCAPE_EXTRA  and  DARCS_ESCAPE_EXTRA. Their values
       should be strings consisting of the verbatim  octets  in  question.  The  do-escapes  take
       precedence  over  the  dont-escapes.  Space  characters  are still escaped at line endings
       though.  The special environment variable DARCS_DONT_ESCAPE_TRAILING_CR turns off escaping
       of carriage return last on the line (DOS style).

   DARCS_TMPDIR and TMPDIR
       Darcs  often creates temporary directories.  For example, the `darcs diff` command creates
       two for the working trees to be diffed.  By default temporary directories are  created  in
       /tmp,  or  if  that  doesn't  exist,  in  _darcs  (within  the current repo).  This can be
       overridden by specifying some other directory  in  the  file  _darcs/prefs/tmpdir  or  the
       environment variable $DARCS_TMPDIR or $TMPDIR.

   DARCS_KEEP_TMPDIR
       If  the  environment  variable  DARCS_KEEP_TMPDIR  is  defined,  darcs will not remove the
       temporary directories it creates.  This is intended primarily for debugging Darcs  itself,
       but  it can also be useful, for example, to determine why your test preference (see `darcs
       setpref`) is failing when you run `darcs record`, but working when run manually.

   DARCS_EMAIL and EMAIL
       Each patch is attributed to its author, usually  by  email  address  (for  example,  `Fred
       Bloggs  <fred@example.net>`).   Darcs  looks in several places for this author string: the
       `--author`   option,   the   files   `_darcs/prefs/author`   (in   the   repository)   and
       `~/.darcs/author`  (in  your home directory), and the environment variables `$DARCS_EMAIL`
       and `$EMAIL`.  If none of those exist, Darcs will prompt you  for  an  author  string  and
       write it to `~/.darcs/author`.  Note that if you have more than one email address, you can
       put them all in `~/.darcs/author`, one author per line.  Darcs will still prompt  you  for
       an author, but it allows you to select from the list, or to type in an alternative.

   SENDMAIL
       On  Unix,  the  `darcs  send`  command relies on sendmail(8).  The `--sendmail-command` or
       $SENDMAIL environment variable can be used to provide an explicit path  to  this  program;
       otherwise the standard locations /usr/sbin/sendmail and /usr/lib/sendmail will be tried.

   DARCS_SLOPPY_LOCKS
       If on some filesystems you get an error of the kind:

           darcs: takeLock [...]: atomic_create [...]: unsupported operation

       you may want to try to export DARCS_SLOPPY_LOCKS=True.

   DARCS_SSH
       Repositories  of  the  form  [user@]host:[dir]  are taken to be remote repositories, which
       Darcs accesses with the external program ssh(1).

       The environment variable $DARCS_SSH can be used to  specify  an  alternative  SSH  client.
       Arguments  may  be  included,  separated by whitespace.  The value is not interpreted by a
       shell, so shell constructs cannot be used; in particular,  it  is  not  possible  for  the
       program name to contain whitespace by using quoting or escaping.

   DARCS_SCP and DARCS_SFTP
       When  reading from a remote repository, Darcs will attempt to run `darcs transfer-mode` on
       the remote host.  This will fail if the remote host only has Darcs  1  installed,  doesn't
       have Darcs installed at all, or only allows SFTP.

       If  transfer-mode fails, Darcs will fall back on scp(1) and sftp(1).  The commands invoked
       can be customized with the environment variables $DARCS_SCP and $DARCS_SFTP  respectively,
       which  behave  like  $DARCS_SSH.   If  the  remote  end  allows  only  sftp,  try  setting
       DARCS_SCP=sftp.

   SSH_PORT
       If this environment variable is set, it will be used as the port number for all SSH  calls
       made  by  Darcs (when accessing remote repositories over SSH).  This is useful if your SSH
       server does  not  run  on  the  default  port,  and  your  SSH  client  does  not  support
       ssh_config(5).    OpenSSH   users  will  probably  prefer  to  put  something  like  `Host
       *.example.net Port 443` into their ~/.ssh/config file.

   HTTP_PROXY, HTTPS_PROXY, FTP_PROXY, ALL_PROXY and NO_PROXY
       If Darcs was built with libcurl, the environment  variables  HTTP_PROXY,  HTTPS_PROXY  and
       FTP_PROXY can be set to the URL of a proxy in the form

           [protocol://]<host>[:port]

       In  which  case  libcurl  will  use the proxy for the associated protocol (HTTP, HTTPS and
       FTP). The environment variable ALL_PROXY can be used to set a single proxy for all libcurl
       requests.

       If  the  environment  variable NO_PROXY is a comma-separated list of host names, access to
       those hosts will bypass proxies defined by the above variables. For example, it  is  quite
       common to avoid proxying requests to machines on the local network with

           NO_PROXY=localhost,*.localdomain

       For  compatibility  with  lynx et al, lowercase equivalents of these environment variables
       (e.g. $http_proxy) are also understood  and  are  used  in  preference  to  the  uppercase
       versions.

       If Darcs was not built with libcurl, all these environment variables are silently ignored,
       and there is no way to use a web proxy.

   DARCS_PROXYUSERPWD
       If  Darcs  was  built  with  libcurl,  and  you  are  using  a  web  proxy  that  requires
       authentication,  you  can set the $DARCS_PROXYUSERPWD environment variable to the username
       and password expected by the proxy, separated by a colon.  This  environment  variable  is
       silently ignored if Darcs was not built with libcurl.

   DARCS_GET_FOO and DARCS_APPLY_FOO
       When  trying  to  access  a  repository with a URL beginning foo://, darcs will invoke the
       program specified by the DARCS_GET_FOO environment variable (if defined) to download  each
       file,  and  the command specified by the DARCS_APPLY_FOO environment variable (if defined)
       when pushing to a foo:// URL.

       This method overrides all other ways of getting `foo://xxx` URLs.

       Note that each command should be constructed so that it sends the  downloaded  content  to
       STDOUT, and the next argument to it should be the URL.  Here are some examples that should
       work for DARCS_GET_HTTP:

           fetch -q -o -
           curl -s -f
           lynx -source
           wget -q -O -

       Apart from such toy examples, it is likely that you will need to manipulate  the  argument
       before  passing  it  to  the actual fetcher program.  For example, consider the problem of
       getting read access to a repository on a CIFS (SMB) share without mount privileges:

           export DARCS_GET_SMB='smbclient -c get'
           darcs get smb://fs/twb/Desktop/hello-world

       The above command will not work for several reasons.   Firstly,  Darcs  will  pass  it  an
       argument  beginning  with `smb:`, which smbclient does not understand.  Secondly, the host
       and  share  `//fs/twb`  must  be  presented  as  a   separate   argument   to   the   path
       `Desktop/hello-world`.   Thirdly,  smbclient  requires that `get` and the path be a single
       argument (including a space), rather than two separate  arguments.   Finally,  smbclient's
       `get`  command  writes  the file to disk, while Darcs expects it to be printed to standard
       output.

       In principle, we could get around such problems by making the  variable  contain  a  shell
       script,  unfortunately,  Darcs  splits  the  command on whitespace and does not understand
       quotation or escaping.  Therefore, we instead need to put commands in separate, executable
       scripts.

       Continuing     our     smbclient    example,    we    create    an    executable    script
       `~/.darcs/libexec/get_smb` with the following contents:

           #!/bin/bash -e
           IFS=/ read host share file <<<'${1#smb://}'
           smbclient //$host/$share -c 'get $file -'

       And at last we can say

           export DARCS_GET_SMB=~/.darcs/libexec/get_smb
           darcs get smb://fs/twb/Desktop/hello-world

       The APPLY command will be called with a darcs patchfile piped into its standard input.

   DARCS_CONNECTION_TIMEOUT
       Set the maximum time in seconds that darcs allows and connection to take. If the  variable
       is not specified the default are 30 seconds. This option only works with curl.

FILES

   _darcs/prefs/binaries
       This  file  contains  a  list  of extended regular expressions, one per line.  A file path
       matching any of these expressions is assumed  to  contain  binary  data  (not  text).  The
       entries in ~/.darcs/binaries (if it exists) supplement those in this file.

       Blank  lines,  and lines beginning with an octothorpe (#) are ignored.  See regex(7) for a
       description of extended regular expressions.

   _darcs/prefs/boring
       This file contains a list of extended regular expressions,  one  per  line.  A  file  path
       matching  any  of  these  expressions will be filtered out during `darcs add', or when the
       `--look-for-adds' flag is  passed  to  `darcs  whatsnew'  and  `record'.  The  entries  in
       ~/.darcs/boring (if it exists) supplement those in this file.

       Blank  lines,  and lines beginning with an octothorpe (#) are ignored.  See regex(7) for a
       description of extended regular expressions.

BUGS

       At http://bugs.darcs.net/ you can find a list of known bugs in Darcs.  Unknown bugs can be
       reported  at  that  site  (after  creating  an  account)  or  by  emailing  the  report to
       bugs@darcs.net.

SEE ALSO

       The Darcs website  provides  a  lot  of  additional  information.   It  can  be  found  at
       http://darcs.net/

LICENSE

       Darcs  is  free  software; you can redistribute it and/or modify it under the terms of the
       GNU General Public License as published by the Free Software Foundation; either version 2,
       or (at your option) any later version.

                                         2.10.2 (release)                                DARCS(1)