{ "mode": "man", "parameter": "DUCK", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/DUCK/1/json", "generated": "2026-10-22T12:55:57Z", "synopsis": "duck [ OPTION ]... [-f file] [-u file] [-c file] [URL]", "sections": { "NAME": { "content": "duck - the Debian Url ChecKer\n", "subsections": [] }, "SYNOPSIS": { "content": "duck [ OPTION ]... [-f file] [-u file] [-c file] [URL]\n", "subsections": [] }, "DESCRIPTION": { "content": "duck extracts links, email address domains and VCS-* entries from the following files:\n\no debian/control\n\no debian/upstream, debian/upstream-metadata.yaml and debian/upstream/metadata\n\no debian/copyright\n\no DEP-3 patch files in every directory a series file is found\n\no systemd.unit files (*.socket, *.device, *.mount, *.automount, *.swap, *.target,\n*.path, *.time, *.snapshot, *.slice, *.scope)\n\no Appstream files (*.appdata)\n\nIf an URL is supplied, duck uses dget to download the specified URL and processes the down‐\nloaded source package (*.dsc file) instead of working on the current directory.\n\nIt tries to access those VCS-* entries and URLs using the appropriate tool to find out\nwhether the given URLs or entries are broken or working. If errors are detected, the file‐\nname, fieldname and URL/email of the broken entry are displayed.\n\nduck will search for the default files (see above) and skip them silently, if they cannot be\nfound. If specific filenames for options -c, -f or -u are given, and one of those files can‐\nnot be found, duck exits with exit code 2.\n\nEmail address domains are checked for existing MX records, A records, or AAAA records, in\nthis order. If none of these 3 are found for a given domain, it is considered broken.\n\nChecks results are displayed with 3 different error levels\n\n\nO: (OK) Indicates that the given check did not result in an error. Only shown if -n is\nused.\n\nI: (Information) Indicates informational warnings, suchs as missing helper tools as well\nas failing checks based on searches in unstructured text files, which sometimes lead\nto false positives.\n\nE: (Error) Indicates failing checks based on data from well-defined fields (e.g. Home‐\npage: entry in debian/control).\n\nand 3 different certainty-levels\n\n", "subsections": [ { "name": "certain", "content": "Data taken from well defined fields. As the format of this field is specified (e.g.\nDebian Policy, etc.), it can be checked by the appropriate tools. If this check then\nfails, the data in the field is certainly erroneous.\n" }, { "name": "possible", "content": "Data extracted using regular expressions (e.g. email addresses, URLs). This might lead\nto false positives, so the check result is possibly a false positive.\n" }, { "name": "wild-guess", "content": "Data extracted from websites, by using regular expressions. This is still experimental\nand probably buggy, hence the \"wild-guess\".\n" } ] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-n", "content": "", "flag": "-n" }, { "name": "-q", "content": "", "flag": "-q" }, { "name": "-v", "content": "--modules-dir=DIRECTORY\nspecify modules directory. Mostly useful for developing new checks. If this parameter\nis specified, only modules defined in this directory are used. You have to copy all\n*.pm files from /usr/share/duck/lib/checks to the directory specified.\n\n--color=[WHEN]\nSpecify when to emit escape sequences to the output. Available options are:\n\nauto Emit color escape codes on STDOUT/STDERR, no color if output is piped to\na file or the current terminal is not capable of displaying colors.\n\n\n\n\nalways Always emit color escape codes.\n\n\n\n\nnever Never emit color escape codes.\n\n\n\n\n--no-https do not try to find matching https URLs to http URLs. See also the DUCKNOHTTPS\nenvironment variable.\n", "flag": "-v" }, { "name": "--no-check-certificate", "content": "do not check if SSL certificates autenticity. This is highly discouraged!\n", "long": "--no-check-certificate" }, { "name": "--missing-helpers", "content": "display list of missing external helper tools and exits.\n\n--version display copyright and version information\n", "long": "--missing-helpers" }, { "name": "-f", "content": "", "flag": "-f" }, { "name": "-F", "content": "", "flag": "-F" }, { "name": "-u", "content": "bian/upstream, debian/upstream-metadata.yaml and debian/upstream/metadata.\n", "flag": "-u" }, { "name": "-U", "content": "", "flag": "-U" }, { "name": "-c", "content": "", "flag": "-c" }, { "name": "-C", "content": "", "flag": "-C" }, { "name": "-P", "content": "", "flag": "-P" }, { "name": "-A", "content": "", "flag": "-A" }, { "name": "-S", "content": "", "flag": "-S" }, { "name": "-l", "content": "fied. Specify one entry per line. This also disables all other check modules\nsearching for entries in various files.\n\n", "flag": "-l" }, { "name": "--disable-urlfix=", "content": "disables the specified url fix(es). An urlfix tries to remove leading/trailing\ncharacters from extracted URLs, like trailing dots or parentheses. Using this\nparameter enables all urlfixes minus the specified ones.\n\n", "long": "--disable-urlfix", "arg": "" }, { "name": "--enable-urlfix=", "content": "enables the specified url fix(es). Using this parameter disabled all urlfixes\nminus the specified ones.\n\n\nThe following urlfixes are available:\n\nTRAILINGCOLON Removes trailing colon \":\" character.\n\n\n\nTRAILINGPARENDOT Removes the string \").\" from the end of the URL.\n\n\nTRAILINGPUNCTUATION Removes trailing \".\" and \",\" characters.\n\n\nTRAILINGQUOTES Removes trailing single quotes \"'\" characters. Note: Double\nquotes (\") are already correctly handled by the used perl regex matchers.\n\n\nTRAILINGSLASHDOT Removes the string \"/.\" (without the quotes) from the end\nof the URL.\n\n\nTRAILINGSLASHPAREN Removes the string \"/)\" (without the quotes) from the end\nof the URL.\n\n", "long": "--enable-urlfix", "arg": "" }, { "name": "--tasks=[number]", "content": "Specify the number of checks allowed to run in parallel. Default value is 24.\nThis value must be an integer value >0.\n\n\nAll urlfixes are enabled by default.\n\n\n\n\n", "long": "--tasks", "arg": "[number]" } ] }, "ENVIRONMENT VARIABLES": { "content": "DUCKNOHTTPS\nIf this variable is set, do not try to find matching https URLs to http URLs.\n\nXDGCONFIGHOME\nif this variable is set, use the config file (if any) $XDGHOME/duck/duck.conf. The\ndefault value is $HOME/.config/duck/duck.conf .\n\nXDGCONFIGDIRS\ndefines the preference-ordered set of base directories to search for configuration\nfiles in addition to the XDGCONFIGHOME base directory. The directories in XDGCON‐\nFIGDIRS should be separated with a colon ':'.\n\n\n\n", "subsections": [] }, "EXAMPLE": { "content": "To run duck, change your working directory to an extracted Debian source package and run:", "subsections": [ { "name": "duck", "content": "" } ] }, "EXIT STATUS": { "content": "0 Success, no errors\n\n1 Error(s) detected\n\n2 User-specified file not found\n\n", "subsections": [] }, "FILES": { "content": "debian/duck-overrides\nOverrides-file in the Debian package source tree. This files contains a list of URL\nregexs which should not be reported as down/broken. This might be useful in cases,\nwhere URLs are extracted from old/outdated copyright-files or patches, which will\nnever ever be working, and which will then lead to false positives. Please see an ex‐\nample in /usr/share/doc/duck/examples.\n\nduck.conf\nConfig file which contains the regular expressions used to detect parked domains and\nredirected websites. The default file is in /etc/duck/duck.conf. duck also honors the\nXDG Base Directory Specification, see the section ENVIRONMENT VARIABLES for details.\nSearch order for duck.conf is:\n\n$XDGCONFIGHOME/duck/duck.conf (default: $HOME/.config/duck/duck.conf)\n\n/etc/duck/duck.conf\n\n/$XDGCONFIGDIRS (default: /etc/xdg/duck/duck.conf)\n\nPlease see the XDG Base Directory Specification (https://specifications.freedesk‐\ntop.org/basedir-spec/basedir-spec-latest.html) for more details.\n\n", "subsections": [] }, "SEE ALSO": { "content": "Please see http://duck.debian.net/ for additional information as well as an overview of duck\nchecks run on all source packages in Debian/unstable.\n\n2017-08-10 DUCK(1)", "subsections": [] } }, "summary": "duck - the Debian Url ChecKer", "flags": [ { "flag": "-n", "long": null, "arg": null, "description": "" }, { "flag": "-q", "long": null, "arg": null, "description": "" }, { "flag": "-v", "long": null, "arg": null, "description": "--modules-dir=DIRECTORY specify modules directory. Mostly useful for developing new checks. If this parameter is specified, only modules defined in this directory are used. You have to copy all *.pm files from /usr/share/duck/lib/checks to the directory specified. --color=[WHEN] Specify when to emit escape sequences to the output. Available options are: auto Emit color escape codes on STDOUT/STDERR, no color if output is piped to a file or the current terminal is not capable of displaying colors. always Always emit color escape codes. never Never emit color escape codes. --no-https do not try to find matching https URLs to http URLs. See also the DUCKNOHTTPS environment variable." }, { "flag": "", "long": "--no-check-certificate", "arg": null, "description": "do not check if SSL certificates autenticity. This is highly discouraged!" }, { "flag": "", "long": "--missing-helpers", "arg": null, "description": "display list of missing external helper tools and exits. --version display copyright and version information" }, { "flag": "-f", "long": null, "arg": null, "description": "" }, { "flag": "-F", "long": null, "arg": null, "description": "" }, { "flag": "-u", "long": null, "arg": null, "description": "bian/upstream, debian/upstream-metadata.yaml and debian/upstream/metadata." }, { "flag": "-U", "long": null, "arg": null, "description": "" }, { "flag": "-c", "long": null, "arg": null, "description": "" }, { "flag": "-C", "long": null, "arg": null, "description": "" }, { "flag": "-P", "long": null, "arg": null, "description": "" }, { "flag": "-A", "long": null, "arg": null, "description": "" }, { "flag": "-S", "long": null, "arg": null, "description": "" }, { "flag": "-l", "long": null, "arg": null, "description": "fied. Specify one entry per line. This also disables all other check modules searching for entries in various files." }, { "flag": "", "long": "--disable-urlfix", "arg": "", "description": "disables the specified url fix(es). An urlfix tries to remove leading/trailing characters from extracted URLs, like trailing dots or parentheses. Using this parameter enables all urlfixes minus the specified ones." }, { "flag": "", "long": "--enable-urlfix", "arg": "", "description": "enables the specified url fix(es). Using this parameter disabled all urlfixes minus the specified ones. The following urlfixes are available: TRAILINGCOLON Removes trailing colon \":\" character. TRAILINGPARENDOT Removes the string \").\" from the end of the URL. TRAILINGPUNCTUATION Removes trailing \".\" and \",\" characters. TRAILINGQUOTES Removes trailing single quotes \"'\" characters. Note: Double quotes (\") are already correctly handled by the used perl regex matchers. TRAILINGSLASHDOT Removes the string \"/.\" (without the quotes) from the end of the URL. TRAILINGSLASHPAREN Removes the string \"/)\" (without the quotes) from the end of the URL." }, { "flag": "", "long": "--tasks", "arg": "[number", "description": "Specify the number of checks allowed to run in parallel. Default value is 24. This value must be an integer value >0. All urlfixes are enabled by default." } ], "examples": [ "To run duck, change your working directory to an extracted Debian source package and run:" ], "see_also": [] }