Provided by: calibre_3.46.0+dfsg-1_all bug

NAME

       calibredb - calibredb

          calibredb kommando [valgmuligheder] [argumenter]

       calibredb  is  the  command  line  interface  to  the  calibre  database.  It  has several
       sub-commands, documented below.

       calibredb can be used to manipulate either a calibre  database  specified  by  path  or  a
       calibre  Content  server running either on the local machine or over the internet. You can
       start a calibre Content server using either the calibre-server  program  or  in  the  main
       calibre  program  click  Connect/share   →  Start Content server. Since calibredb can make
       changes to your calibre libraries, you must setup  authentication  on  the  server  first.
       There are two ways to do that:

          · If  you plan to connect only to a server running on the same computer, you can simply
            use the --enable-local-write option of the content  server,  to  allow  any  program,
            including  calibredb,  running  on the local computer to make changes to your calibre
            data. When running the server from the  main  calibre  program,  this  option  is  in
            Preferences → Sharing over the net → Advanced.

          · If  you  want to enable access over the internet, then you should setup user accounts
            on the server and use the --username and --password options to calibredb to  give  it
            access.   You   can  setup  user  authentication  for  calibre-server  by  using  the
            --enable-auth option and using --manage-users to create the user  accounts.   If  you
            are  running the server from the main calibre program, use Preferences → Sharing over
            the net → Require username/password.

       To connect to a running Content server, pass the URL of the server to  the  --with-library
       option, see the documentation of that option for details and examples.

       · GLOBAL OPTIONS

       · list

       · add

         · ADDING FROM DIRECTORIES

       · remove

       · add_format

       · remove_format

       · show_metadata

       · set_metadata

       · export

       · catalog

         · EPUB OPTIONS

       · saved_searches

       · add_custom_column

       · custom_columns

       · remove_custom_column

       · set_custom

       · restore_database

       · check_library

       · list_categories

       · backup_metadata

       · clone

       · embed_metadata

       · search

GLOBAL OPTIONS

       --help, -h
              show this help message and exit

       --library-path, --with-library
              Path to the calibre library. Default is to use the path stored in the settings. You
              can also connect  to  a  calibre  Content  server  to  perform  actions  on  remote
              libraries.  To  do  so  use a URL of the form: http://hostname:port/#library_id for
              example, http://localhost:8080/#mylibrary. library_id is  the  library  id  of  the
              library  you  want  to  connect  to  on the Content server. You can use the special
              library_id value of - to get a list of library ids available  on  the  server.  For
              details    on    how    to    setup    access    via    a   Content   server,   see
              https://manual.calibre-ebook.com/generated/en/calibredb.html.

       --password
              Password for connecting to a calibre Content server.  To  read  the  password  from
              standard  input,  use the special value: <stdin>. To read the password from a file,
              use: <f:/path/to/file> (i.e. <f: followed by the  full  path  to  the  file  and  a
              trailing  >). The angle brackets in the above are required, remember to escape them
              or use quotes for your shell.

       --username
              Username for connecting to a calibre Content server

       --version
              show program's version number and exit

LIST

          calibredb list [options]

       Liste de tilgængelige bøger i calibre databasen.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --ascending
              Sortér resultaterne i stigende orden

       --fields, -f
              The  fields  to  display  when  listing  books  in  the database. Should be a comma
              separated list of fields. Available fields: author_sort, authors, comments,  cover,
              formats,  identifiers,  isbn, languages, last_modified, pubdate, publisher, rating,
              series, series_index, size, tags, timestamp, title,  uuid  Default:  title,authors.
              The  special  field  "all"  can  be  used  to select all fields. In addition to the
              builtin fields above, custom fields are also available as *field_name, for example,
              for a custom field #rating, use the name: *rating

       --for-machine
              Generate  output in JSON format, which is more suitable for machine parsing. Causes
              the line width and separator options to be ignored.

       --limit
              The maximum number of results to display. Default: all

       --line-width, -w
              Maksimale  bredde  af  en  enkelt  linje  i  output.  Standard  er   at   detektere
              skærmstørrelsen.

       --prefix
              Præfiks for alle filstier. Standard er en absolut sti til biblioteksmappen.

       --search, -s
              Filtrér  resultaterne  efter  søgeforespørgslen.  For  at  finde ud af formatet for
              søgeforespørgslen, venligst se den søge relaterede dokumentation i  brugermanualen.
              Standard er ingen filtrering.

       --separator
              Strengen anvendt til at separere felter. Standard er et mellemrum.

       --sort-by
              The  field  by  which  to sort the results. Available fields: author_sort, authors,
              comments, cover, formats, identifiers,  isbn,  languages,  last_modified,  pubdate,
              publisher,  rating,  series,  series_index,  size,  tags,  timestamp,  title,  uuid
              Default: id

ADD

          calibredb add [options] fil1 fil2 fil3 ...

       Tilføj de specificerede filer som bøger til databasen. Du kan også specificere mapper,  se
       mappe relaterede options nedenfor.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --authors, -a
              Set the authors of the added book(s)

       --cover, -c
              Path to the cover to use for the added book

       --duplicates, -d
              Tilføj bøger til databasen selvom de allerede eksisterer. Sammenligning er  baseret
              på bogtitlerne.

       --empty, -e
              Tilføj en tom bog (en bog uden formater)

       --identifier, -I
              Set the identifiers for this book, for e.g. -I asin:XXX -I isbn:YYY

       --isbn, -i
              Set the ISBN of the added book(s)

       --languages, -l
              A comma separated list of languages (best to use ISO639 language codes, though some
              language names may also be recognized)

       --series, -s
              Set the series of the added book(s)

       --series-index, -S
              Set the series number of the added book(s)

       --tags, -T
              Set the tags of the added book(s)

       --title, -t
              Sæt titlen på de tilføjede bøger

   ADDING FROM DIRECTORIES
       Options to control the adding of books from directories. By default only files  that  have
       extensions of known e-book file types are added.

       --add  A  filename (glob) pattern, files matching this pattern will be added when scanning
              directories for files, even if they are not of a known e-book  file  type.  Can  be
              specified multiple times for multiple patterns.

       --ignore
              A  filename  (glob)  pattern,  files  matching  this  pattern  will be ignored when
              scanning directories for files.  Can  be  specified  multiple  times  for  multiple
              patterns. For e.g.: *.pdf will ignore all pdf files

       --one-book-per-directory, -1
              Formod  at  hver  mappe  kun  har  én  enkelt  logisk bog og at alle filer i den er
              forskellige e-bogsformater af denne bog

       --recurse, -r
              Behandle mapper rekursivt

REMOVE

          calibredb remove ids

       Remove the books identified by ids from the database. ids should be a comma separated list
       of  id  numbers  (you  can  get  id  numbers  by  using  the search command). For example,
       23,34,57-85 (when specifying a range, the last number in the range is not included).

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --permanent
              Do not use the recycle bin

ADD_FORMAT

          calibredb add_format [options] id ebook_file

       Add  the  e-book in ebook_file to the available formats for the logical book identified by
       id. You can get id by using the search command.  If  the  format  already  exists,  it  is
       replaced, unless the do not replace option is specified.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --dont-replace
              Do not replace the format if it already exists

REMOVE_FORMAT

          calibredb remove_format [options] id fmt

       Remove the format fmt from the logical book identified by id. You can get id by using  the
       search  command.  fmt  should  be a file extension like LRF or TXT or EPUB. If the logical
       book does not have fmt available, do nothing.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

SHOW_METADATA

          calibredb show_metadata [options] id

       Show  the metadata stored in the calibre database for the book identified by id.  id is an
       id number from the search command.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --as-opf
              Udskriv metadata i OPF-form (XML)

SET_METADATA

          calibredb set_metadata [options] id [/path/to/metadata.opf]

       Set the metadata stored in the calibre database for the book identified by id from the OPF
       file metadata.opf. id is an id number from the search command. You can get  a  quick  feel
       for the OPF format by using the --as-opf switch to the show_metadata command. You can also
       set the metadata of individual fields with the --field option.  If  you  use  the  --field
       option, there is no need to specify an OPF file.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --field, -f
              The field to set. Format is field_name:value, for example: --field  tags:tag1,tag2.
              Use  --list-fields  to  get  a list of all field names. You can specify this option
              multiple times to set multiple fields. Note: For languages you must use the  ISO639
              language codes (e.g. en for English, fr for French and so on). For identifiers, the
              syntax is --field identifiers:isbn:XXXX,doi:YYYYY. For boolean (yes/no) fields  use
              true and false or yes and no.

       --list-fields, -l
              List the metadata field names that can be used with the --field option

EXPORT

          calibredb export [options] ids

       Export  the books specified by ids (a comma separated list) to the filesystem.  The export
       operation saves all formats of the book, its cover and metadata (in an opf file). You  can
       get id numbers from the search command.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --all  Eksporter alle bøger i databasen, listen over id'er ignoreres.

       --dont-asciiize
              Normalt  vil  calibre  konvertere  alle  ikke-engelske   bogstaver   til   engelske
              ækvivalenter  for  filnavnene.  ADVARSEL: Hvis du slår dette fra, vil du nok opleve
              fejl under gemning, afhængig af hvor godt filsystemet  du  gemmer  i,  understøtter
              unicode. Specificering af denne switch vil slå denne opførsel fra.

       --dont-save-cover
              Normally,  calibre  will  save  the  cover in a separate file along with the actual
              e-book files. Specificering af denne switch vil slå denne opførsel fra.

       --dont-update-metadata
              Normalt vil calibre opdatere metadataene i  de  gemte  filer  fra  hvad  der  er  i
              calibre-biblioteket.  Gør  gem-til-disk  langsommere. Specificering af denne switch
              vil slå denne opførsel fra.

       --dont-write-opf
              Normalt, vil calibre skrive metadataene  til  en  separat  OPF-fil  sammen  med  de
              aktuelle e-bog-filer. Specificering af denne switch vil slå denne opførsel fra.

       --formats
              Kommasepareret liste af formater, som gemmes for hver bog. Som standard gemmes alle
              tilgængelige formater.

       --progress
              Report progress

       --replace-whitespace
              Udskift blanktegn med bundstreger.

       --single-dir
              Eksportér alle bøger til en enkel mappe

       --template
              The template to control the filename and directory structure of  the  saved  files.
              Default is "{author_sort}/{title}/{title} - {authors}" which will save books into a
              per-author subdirectory with  filenames  containing  title  and  author.  Available
              controls  are:  {author_sort, authors, id, isbn, languages, last_modified, pubdate,
              publisher, rating, series, series_index, tags, timestamp, title}

       --timefmt
              The format in which to display dates. %d - day, %b - month, %m - month number, %Y -
              year. Default is: %b, %Y

       --to-dir
              Eksportér bøger til den angivne mappe. Standardmappen er .

       --to-lowercase
              Konvertér stier til småbogstaver.

CATALOG

          calibredb catalog /path/to/destination.(csv|epub|mobi|xml...) [options]

       Export  a  catalog  in format specified by path/to/destination extension.  Options control
       how entries are displayed in the generated catalog output.  Note  that  different  catalog
       formats support different sets of options.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --ids, -i
              Kommasepareret liste af database IDs til kataloget. Hvis erklæret, --search  bliver
              ignoreret. Standard: all

       --search, -s
              Filtrér  resultatet med søgeforespørgsel. Vedrørende formatet for søgeforespørgsel,
              venligst  se  søgerelateret  dokumentation  i   brugermanualen.   Standard:   Ingen
              filtrering

       --verbose, -v
              Vis detaljeret output-information. Anvendeligt ved fejlfinding

   EPUB OPTIONS
       --catalog-title
              Title  of  generated catalog used as title in metadata. Default: 'My Books' Applies
              to: AZW3, EPUB, MOBI output formats

       --cross-reference-authors
              Create cross-references  in  Authors  section  for  books  with  multiple  authors.
              Default: 'False' Applies to: AZW3, EPUB, MOBI output formats

       --debug-pipeline
              Save  the  output from different stages of the conversion pipeline to the specified
              directory. Useful if you are unsure at which stage of the conversion process a  bug
              is occurring. Default: 'None' Applies to: AZW3, EPUB, MOBI output formats

       --exclude-genre
              Regex  describing tags to exclude as genres. Default: '[.+]|^+$' excludes bracketed
              tags, e.g. '[Project Gutenberg]', and '+', the default tag for read books.  Applies
              to: AZW3, EPUB, MOBI output formats

       --exclusion-rules
              Specifies the rules used to exclude books from the generated catalog. The model for
              an exclusion rule is either ('<rule name>','Tags','<comma-separated list of tags>')
              or   ('<rule   name>','<custom   column>','<pattern>').  For  example:  (('Archived
              books','#status','Archived'),) will exclude a book with a value  of  'Archived'  in
              the  custom  column  'status'.  When  multiple rules are defined, all rules will be
              applied. Default:  "(('Catalogs','Tags','Catalog'),)" Applies to: AZW3, EPUB,  MOBI
              output formats

       --generate-authors
              Include 'Authors' section in catalog. Default: 'False' Applies to: AZW3, EPUB, MOBI
              output formats

       --generate-descriptions
              Include 'Descriptions' section in catalog. Default: 'False' Applies to: AZW3, EPUB,
              MOBI output formats

       --generate-genres
              Include  'Genres' section in catalog. Default: 'False' Applies to: AZW3, EPUB, MOBI
              output formats

       --generate-recently-added
              Include 'Recently Added' section in catalog. Default:  'False'  Applies  to:  AZW3,
              EPUB, MOBI output formats

       --generate-series
              Include  'Series' section in catalog. Default: 'False' Applies to: AZW3, EPUB, MOBI
              output formats

       --generate-titles
              Include 'Titles' section in catalog. Default: 'False' Applies to: AZW3, EPUB,  MOBI
              output formats

       --genre-source-field
              Source field for 'Genres' section. Default: 'Mærkater' Applies to: AZW3, EPUB, MOBI
              output formats

       --header-note-source-field
              Custom field containing note text to insert  in  Description  header.  Default:  ''
              Applies to: AZW3, EPUB, MOBI output formats

       --merge-comments-rule
              #<custom  field>:[before|after]:[True|False]  specifying:   <custom  field>  Custom
              field containing notes to merge with Comments  [before|after]  Placement  of  notes
              with  respect  to  Comments   [True|False]  - A horizontal rule is inserted between
              notes and Comments Default: '::' Applies to: AZW3, EPUB, MOBI output formats

       --output-profile
              Specifies the output profile. In some cases,  an  output  profile  is  required  to
              optimize the catalog for the device. For example, 'kindle' or 'kindle_dx' creates a
              structured Table of Contents with Sections and Articles.  Default:  'None'  Applies
              to: AZW3, EPUB, MOBI output formats

       --prefix-rules
              Specifies  the rules used to include prefixes indicating read books, wishlist items
              and other  user-specified  prefixes.  The  model  for  a  prefix  rule  is  ('<rule
              name>','<source  field>','<pattern>','<prefix>').  When multiple rules are defined,
              the    first    matching    rule    will     be     used.     Default:     "(('Read
              books','tags','+',''),('Wishlist  item','tags','Wishlist','×'))" Applies to: AZW3,
              EPUB, MOBI output formats

       --preset
              Use a named preset created with the GUI catalog builder.  A  preset  specifies  all
              settings  for  building  a  catalog.  Default:  'None' Applies to: AZW3, EPUB, MOBI
              output formats

       --thumb-width
              Size hint (in inches) for book covers in catalog. Range: 1.0 - 2.0  Default:  '1.0'
              Applies to: AZW3, EPUB, MOBI output formats

       --use-existing-cover
              Replace  existing  cover  when generating the catalog. Default: 'False' Applies to:
              AZW3, EPUB, MOBI output formats

SAVED_SEARCHES

          calibredb saved_searches [options] (list|add|remove)

       Manage the saved searches stored in this database.  If you try to add a query with a  name
       that already exists, it will be replaced.

       Syntax for adding:

       calibredb saved_searches add search_name search_expression

       Syntax for removing:

       calibredb saved_searches remove search_name

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

ADD_CUSTOM_COLUMN

          calibredb add_custom_column [options] label navn datatype

       Opret en brugerdefineret kolonne. label er et maskinvenligt kolonnenavn. Må ikke indeholde
       mellemrum  eller  koloner.  name  er  det menneskevenlige kolonnenavn.  datatype er en af:
       bool, comments, composite, datetime, enumeration, float, int, rating, series, text

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --display
              A  dictionary  of  options  to  customize  how  the  data  in  this  column will be
              interpreted. This is a JSON  string.  For  enumeration  columns,  use  --display"{\
              "enum_values\  ":[\ "val1\ ", \ "val2\ "]}" There are many options that can go into
              the display variable.The options by column type are: composite: composite_template,
              composite_sort,  make_category,contains_html, use_decorations datetime: date_format
              enumeration: enum_values, enum_colors, use_decorations  int,  float:  number_format
              text:  is_names,  use_decorations   The  best  way to find legal combinations is to
              create a custom column of the appropriate type in the GUI then look at  the  backup
              OPF for a book (ensure that a new OPF has been created since the column was added).
              You will see the JSON for the "display" for the new column in the OPF.

       --is-multiple
              Denne kolonne gemmer mærkat ligesom data (f.eks. multiple kommaseparerede værdier).
              Giver kun mening hvis datatypen er tekst.

CUSTOM_COLUMNS

          calibredb custom_columns [options]

       List available custom columns. Shows column labels and ids.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --details, -d
              Vis detaljer for hver kolonner.

REMOVE_CUSTOM_COLUMN

          calibredb remove_custom_column [options] label

       Remove the custom column identified by label. You  can  see  available  columns  with  the
       custom_columns command.

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --force, -f
              Spørger/spørg ikke efter bekræftelse

SET_CUSTOM

          calibredb set_custom [options] column id value

       Set the value of a custom column for the book identified by id.  You can get a list of ids
       using  the  search  command.   You  can  get  a  list  of  custom  column  names using the
       custom_columns command.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --append, -a
              Hvis  kolonnen  gemmer  multiple  værdier, tilføjes de specificerede værdier til de
              eksisterende, istedet for at overskrive dem.

RESTORE_DATABASE

          calibredb restore_database [options]

       Gendan  denne  database  fra  metadataene   gemt   i   OPF-filerne   i   hver   mappe   af
       calibre-biblioteket. Dette er anvendeligt hvis din metadata.db fil er blevet forvansket.

       ADVARSEL:  Denne  kommando  genopbygger fuldstændigt din database. Du vil miste alle gemte
       søgninger,  brugerdefinerede  kategorier,   plugboards,   gemte   per-bog   konverterings-
       indstillinger  -  og  brugerdefinerede  recipes.  Gendannede metadata vil kun være baseret
       efter hvad der er fundet i OPF-filerne.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --really-do-it, -r
              Skal  opretningen  virkelig  udføres.  Kommanden  vil  ikke  køre,  medmindre denne
              mulighed bliver angivet.

CHECK_LIBRARY

          calibredb check_library [options]

       Udføre  nogle  check  på  filsystemet  som  repræsenterer  et  bibliotek.   Rapporter   er
       invalid_titles,    extra_titles,    invalid_authors,    extra_authors,    missing_formats,
       extra_formats, extra_files, missing_covers, extra_covers, failed_folders

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --csv, -c
              Output i CSV

       --ignore_extensions, -e
              Komma-separeret liste af fil-extensions som ignoreres. Standard: Alle

       --ignore_names, -n
              Komma-separeret liste af navne som ignoreres. Standard: Alle

       --report, -r
              Komma-separeret liste af rapporter. Standard: Alle

LIST_CATEGORIES

          calibredb list_categories [options]

       Laver  en  rapport af kategoriinformationen i databasen.  Informationen er ækvivalenten af
       hvad som vises i mærkatsvinduet.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --categories, -r
              Comma-separated list of category lookup names. Default: all

       --csv, -c
              Output i CSV

       --dialect
              The type of CSV file to produce. Choices: excel, excel-tab

       --item_count, -i
              Output  kun antallet af emner i en kategori, istedet for antallet per emne indenfor
              kategorien

       --width, -w
              Maksimale  bredde  af  en  enkelt  linje  i  output.  Standard  er   at   detektere
              skærmstørrelsen.

BACKUP_METADATA

          calibredb backup_metadata [options]

       Backup  the  metadata  stored  in  the  database  into  individual OPF files in each books
       directory. This normally happens automatically, but you can  run  this  command  to  force
       re-generation of the OPF files, with the --all option.

       Note  that  there  is  normally  no  need  to  do  this,  as  the  OPF files are backed up
       automatically, every time metadata is changed.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --all  Normally, this command only operates on books that have out of date OPF files. This
              option makes it operate on all books.

CLONE

          calibredb clone path/to/new/library

       Create a clone of the current library. This creates a new, empty library that has all  the
       same custom columns, virtual libraries and other settings as the current library.

       The  cloned  library  will  contain  no  books.  If  you  want to create a full duplicate,
       including all books, then simply use your filesystem tools to copy the library folder.

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

EMBED_METADATA

          calibredb embed_metadata [options] book_id

       Update  the  metadata  in  the  actual  book  files stored in the calibre library from the
       metadata in the calibre database.  Normally, metadata is updated only when exporting files
       from  calibre,  this  command is useful if you want the files to be updated in place. Note
       that different file formats support different amounts of metadata. You can use the special
       value  'all'  for  book_id to update metadata in all books. You can also specify many book
       ids separated by spaces and  id  ranges  separated  by  hyphens.  For  example:  calibredb
       embed_metadata 1 2 10-15 23

       Whenever  you  pass arguments to calibredb that have spaces in them, enclose the arguments
       in quotation marks. For example: "/some path/with spaces"

       --only-formats, -f
              Only update metadata in files of the specified format. Specify  it  multiple  times
              for multiple formats. By default, all formats are updated.

SEARCH

          calibredb search [options] search expression

       Search the library for the specified search term, returning a comma separated list of book
       ids matching the search expression. The  output  format  is  useful  to  feed  into  other
       commands that accept a list of ids as input.

       The  search  expression can be anything from calibre's powerful search query language, for
       example: author:asimov title:robot

       Whenever you pass arguments to calibredb that have spaces in them, enclose  the  arguments
       in quotation marks. For example: "/some path/with spaces"

       --limit, -l
              The maximum number of results to return. Default is all results.

AUTHOR

       Kovid Goyal

COPYRIGHT

       Kovid Goyal