Added jdupes notes to the knowledge base

knowledge base/jdupes.md

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+# `jdupes`
+
+## TL;DR
+
+```shell
+# prompt to delete all duplicate files
+jdupes -Zdr directory
+
+# automatically replace duplicate files with hard links to the first encountered
+jdupes -ONLr directory1 directory2 directory3 file
+
+# quickly list all duplicate gz archives
+jdupes -rQX onlyext:gz directory
+
+# delete all duplicates from a folder keeping all other folders intact
+# will need multiple runs
+find -mindepth 1 -maxdepth 1 -type d -not -name directoryWithDuplicates | xargs -I {} -n 1 -t jdupes -drINOZ {} directoryWithDuplicates
+```
+
+## Options
+
+Short | Long                     | Description
+------|--------------------------|------------
+`-@`  | `--loud`                 | output annoying low-level debug info while running
+`-B`  | `--dedupe`               | issue the btrfs _same-extents_ ioctl to trigger a deduplication on disk; jdupes **must be built with btrfs support** for this option to be available
+`-D`  | `--debug`                | show debugging statistics and info at the end of program execution; the feature must be compiled in for this option to work
+`-d`  | `--delete`               | prompt the user for files to preserve, deleting all others
+`-I`  | `--isolate`              | isolate each command-line parameter from one another; only return a match if the files are under different parameters
+`-L`  | `--link-hard`            | replace all duplicate files with hardlinks to the first file in each set of duplicates
+`-m`  | `--summarize`            | summarize duplicate file information
+`-M`  | `--print-summarize`      | print matches and summarize the duplicate file information at the end
+`-N`  | `--no-prompt`            | when used together with `--delete`, preserve the first file in each set of duplicates and delete the others without prompting the user
+`-O`  | `--param-order`          | parameter order preservation is more important than the chosen sort; this is particularly useful with the `-N` option to ensure that automatic deletion behaves in a controllable way
+`-Q`  | `--quick`                | skip byte-for-byte verification of duplicate pairs (use hashes only)
+`-q`  | `--quiet`                | hide progress indicator
+`-r`  | `--recurse`              | for every directory given follow subdirectories encountered within
+`-S`  | `--size`                 | show size of duplicate files
+`-s`  | `--symlinks`             | follow symlinked directories
+`-X`  | `--ext-filter=spec:info` | exclude/filter files based on specified criteria; see the [filter format](#filter-format) section
+`-Z`  | `--soft-abort`           | if the user aborts the program (as with CTRL-C), act on the matches that were found before the abort was received; the default behavior without `-Z` is to abort without taking any actions
+
+
+## Filter format
+
+`jdupes -X filter[:value][size_suffix]`
+
+Some filters take no value or multiple values.
+
+Filters that can take a numeric option generally support the size multipliers `K`/`M`/`G`/`T`/`P`/`E`, with or without an added `iB` or `B`.  
+Multipliers are binary-style unless the `-B` suffix is used, which will use decimal multipliers. For example, 16k or 16kib = 16384; 16kb = 16000. Multipliers are case-insensitive.
+
+Filters have cumulative effects: `jdupes -X size+:99 -X size-:101` will cause only files of exactly 100 bytes in size to be included.
+
+Extension matching is case-insensitive. Path substring matching is case-sensitive.
+
+Supported filters:
+
+- `size[+-=]:number[suffix]`: match only if size is greater (+), less than (-), or equal to (=) the specified number; the +/- and = specifiers can be combined, i.e. `size+=:4K` will only consider files with a size greater than or equal to 4 kilobytes (4096 bytes)
+- `noext:ext1[,ext2,...]`: exclude files with certain extension(s), specified as a comma-separated list; do **not** use a leading dot
+- `onlyext:ext1[,ext2,...]`: only include files with certain extension(s), specified as a comma-separated list; do not use a leading dot
+- `nostr:text_string`: exclude all paths containing the substring *text_string*; this scans the full file path, so it can be used to match directories, i.e. `-X nostr:dir_name/`
+- `onlystr:text_string`: require all paths to contain the substring *text_string*; this scans the full file path, so it can be used to match directories, i.e. `-X onlystr:dir_name/`
+- `newer:datetime`: only include files newer than the specified date; use the date/time format _YYYY-MM-DD HH:MM:SS_; time is optional
+- `older:datetime`: only include files older than the specified date; use the date/time format _YYYY-MM-DD HH:MM:SS_; time is optional
+
+## Sources
+
+- Jdupes' [github] page
+
+[github]: https://github.com/jbruchon/jdupes