README (p.docfd.2.1.0.doc.README)

Installation

Statically linked binaries are available via GitHub releases

Features

Multithreaded indexing and searching
Multiline fuzzy search of multiple files or a single file
Swap between multi-file view and single file view on the fly
Content view pane that shows the snippet surrounding the search result selected
Text editor and PDF viewer integration

Integration details

Text editor integration

Docfd uses the text editor specified by $VISUAL (this is checked first) or $EDITOR.

Docfd opens the file at first line of search result for the following editors:

nano
nvim/vim/vi
kak
hx
emacs
micro
jed/xjed

PDF viewer integration

Docfd guesses the default PDF viewer based on the output of xdg-mime query default application/pdf, and invokes the viewer either directly or via flatpak depending on where the desktop file can be first found in the list of directories specified by $XDG_DATA_DIRS.

Docfd opens the file at first page of the search result and starts a text search of the most unique word of the matched phrase within the same page for the following viewers:

okular
evince
xreader
atril

Docfd opens the file at first page of the search result for the following viewers:

mupdf

Usage

Read from piped stdin

command | docfd

Docfd uses Single file view when source of document is piped stdin.

Files specified as arguments to docfd are ignored in this case.

Read from files

docfd [PATH...]

The list of paths can contain directories. Each directory in the list is scanned recursively for files with one of the following extensions by default:

.txt
.md
.pdf

You can change the file extensions to use via --exts, or add onto the list of extensions via --add-exts.

If the list of paths is empty, then Docfd defaults to scanning the current directory ..

If any of the file ends with .pdf, then pdftotext is required to continue.

If exactly one file is specified in the list of paths, then Docfd uses Single file view. Otherwise, Docfd uses Multi-file view.

If any of the path is ?, then file selection of the discovered files via fzf is invoked.

Multi-file view

The default TUI is divided into four sections:

Left is the list of documents which satisfy the search phrase
Top right is the content view of the document which tracks the search result selected
Bottom right is the ranked search result list
Bottom pane consists of:
- Status bar
- Key binding info
- File content requirement field
- Search field

Controls

Docfd operates in modes, the initial mode is Navigation mode.

Navigation mode

Scroll down the document list
- j
- Down arrow
- Page down
- Scroll down with mouse wheel when hovering above the area
Scroll up the document list
- k
- Up arrow
- Page up
- Scroll up with mouse wheel when hovering above the area
Scroll down the search result list
- Shift+J
- Shift+Down arrow
- Shift+Page down
- Scroll down with mouse wheel when hovering above the area
Scroll up the document list
- Shift+K
- Shift+Up arrow
- Shift+Page up
- Scroll up with mouse wheel when hovering above the area
Open document
- Enter
  - Docfd tries to use $VISUAL first, if that fails then Docfd tries $EDITOR
Switch to single file view
- Tab
Switch to Require content mode
- ?
Switch to Search mode
- /
Clear search phrase
- x
Exit Docfd
- Esc, Ctrl+C or Ctrl+Q

Search mode

Search field is active in this mode
Enter to confirm search phrase and exit the mode

Require content mode

Required content field is active in this mode
Enter to confirm file content requirements and exit the mode

Search phrase and search procedure

Document content and user input in the search field are tokenized/segmented in the same way, based on:

Contiguous alphanumeric characters
Individual symbols
Individual UTF-8 characters
Spaces

A search phrase is a list of said tokens.

Search procedure is a DFS through the document index, where the search range for a word is fixed to a configured range surrounding the previous word (when applicable).

A token in the index matches a token in the search phrase if they are:

A case-insensitive exact match
Or a case-insensitive substring match (token in search phrase being the substring)
Or within the configured case-insensitive edit distance threshold

Search results are then ranked using heuristics.

File content requirements

The required content field accepts a content requirement expression.

A content requirement expression is one of:

Search phrase
(expression)
expression & expression
expression | expression

Note that the edit distance is not considered here. Only case-insensitive exact matches or substring matches against the search phrases are considered.

In other words, given the same phrase, it is treated less fuzzily as a content requirement expression compared to being used as a search phrase in the search field.

Single file view

If the specified path to Docfd is not a directory, then single file view is used.

In this view, the TUI is divided into only two sections:

Top is ranked search result list
Bottom is the search interface

Controls

The controls are simplified in single file view, namely Shift is optional for scrolling through search result list.

Navigation mode

Scroll down the search result list
- j
- Down arrow
- Page down
- Shift+J
- Shift+Down arrow
- Shift+Page down
- Scroll down with mouse wheel when hovering above the area
Scroll up the document list
- k
- Up arrow
- Page up
- Shift+K
- Shift+Up arrow
- Shift+Page up
- Scroll up with mouse wheel when hovering above the area
Open document
- Enter
  - Docfd tries to use $VISUAL first, if that fails then Docfd tries $EDITOR
Switch to multi-file view
- Tab
Switch to Search mode
- /
Clear search phrase
- x
Exit Docfd
- Esc, Ctrl+C or Ctrl+Q

Search mode

Search field is active in this mode
Enter to confirm search phrase and exit search mode

Limitations

File auto-reloading is not supported for PDF files, as PDF viewers are invoked in the background via shell. It is possible to support this properly in the ways listed below, but requires a lot of engineering for potentially very little gain:
- Docfd waits for PDF viewer to terminate fully before resuming, but this prohibits viewing multiple search results simultaneously in different PDF viewer instances.
- Docfd manages the launched PDF viewers completely, but these viewers are closed when Docfd terminates.
- Docfd invokes the PDF viewers via shell so they stay open when Docfd terminates. Docfd instead periodically checks if they are still running via the PDF viewers' process IDs, but this requires handling forks.
- Outside of tracking whether the PDF viewer instances interacting with the files are still running, Docfd also needs to set up file update handling either via inotify or via checking file modification times periodically.

Acknowledgement

Demo gifs are made using vhs.