icodein / hgrep

Grep with human-friendly search output

hgrep: Human-friendly GREP

hgrep is a grep tool to search files with given pattern and print the matched code snippets with human-friendly syntax highlighting. In short, it's a fusion of bat and grep or other alternatives like ripgrep.

This is similar to -C option of grep command, but hgrep focuses on human readable outputs. hgrep is useful to survey the matches with contexts around them. When some matches are near enough, hgrep prints the lines within one code snippet. Unlike grep -C, hgrep adopts some heuristics around blank lines to determine efficient number of context lines.

Example:

# With standard grep
grep -nH pattern -R ./dir | hgrep

# With grep alternative tools
rg -nH pattern ./dir | hgrep

As an optional feature, hgrep has builtin grep implementation thanks to ripgrep as library. It's a subset of rg command. And it's faster when there are so many matches since everything is done in the same process.

Example:

# Use builtin subset of ripgrep
hgrep pattern ./dir

hgrep provides two printers to print match results for your use case. Please see 'bat printer v.s. syntect printer' section for the comparison.

• syntect printer: Our own implementation of printer using syntect library. Performance and its output layout are more optimized
• bat printer: Printer built on top of bat's pretty printer implementation, which is battle-tested and provides some unique features

Please see the usage section for more details.

Installation

Binary releases

Visit the releases page and download the zip file for your platform. Unarchive the file and put the executable file in some $PATH directory. Currently the following targets are supported. If you want a binary for some other platform, feel free to make an issue to request it.

• Linux (x86_64)
• macOS (x86_64, aarch64)
• Windows (x86_64)

Via Homebrew

By adding hgrep repository as Homebrew tap, hgrep command can be installed and managed via Homebrew. Currently only for x86_64 macOS and Linux.

brew tap "rhysd/hgrep" "https://github.com/rhysd/hgrep"
brew install hgrep

Via MacPorts

On macOS, you can install hgrep with the following commands through MacPorts:

sudo port selfupdate
sudo port install hgrep

For NetBSD

To install pre-built binaries using the package manager, simply run:

pkgin install hgrep

Or, if you prefer to build from source,

cd /usr/pkgsrc/textproc/hgrep
make install

Via cargo package manager

cargo install hgrep

If you always use hgrep with reading the grep output from stdin and don't want the builtin ripgrep feature, it can be omitted. This reduces the number of dependencies, installation time, and the binary size.

cargo install hgrep --no-default-features --features bat-printer,syntect-printer

To customize features on installation, please see the following 'Feature flags' section for more details.

Feature flags

All features are optional and enabled by default. At least bat-printer or syntect-printer needs to be enabled.

Feature	Description
ripgrep	Built-in grep implementation built on top of ripgrep as library. Performance is better than piping rg in some cases.
bat-printer	Printer implementation built on top of bat's pretty printer, which is battle-tested and provides some unique features.
syntect-printer	Our own printer implementation built with syntect library. Performance and output layout are optimized for our use cases.

For the differences of bat-printer and syntect-printer, see 'bat printer v.s. syntect printer' section.

Usage

Eat grep -nH output

hgrep takes grep results via stdin. Since hgrep expects file paths and line numbers in each line of the output, -nH is necessary at grep command.

grep -nH pattern -R paths... | hgrep [options...]

grep alternative tools like ripgrep, ag, pt, ... are also available because they can output results compatible with grep -nH.

rg -nH pattern paths... | hgrep [options...]

When you want a pager, please use external commands like less. $COLUMNS needs to be passed because terminal width is fixed to 80 characters when the process is piped. If you frequently use a pager, 'Set default command options' section would describe a better way.

grep -nH pattern -R paths... | hgrep --term-width "$COLUMNS" [options...] | less -R

By default, hgrep shows at least 5 lines and at most 5 lines as context of a match. How many context lines is determined by some heuristics around blank lines for efficiency. Minimum context lines can be specified by -c and Maximum context lines can be specified by -C. If you don't want the heuristics, specify the same value to the options like -c 10 -C 10.

# At least 10 context lines and at most 20 context lines
grep -nH pattern -R paths... | hgrep -c 10 -C 20

Builtin ripgrep

Optionally hgrep provides builtin grep implementation. It is a subset of ripgrep since it's built using ripgrep as library. And it's faster when there are so many matches because everything is done in the same process. The builtin grep feature is enabled by default and can be omitted by feature flags.

hgrep [options...] pattern paths...

Though almost all useful options are implemented, the builtin grep implementation is a subset of ripgrep. If you need full functionalities, use rg command and eat its output by hgrep via stdin. Currently there are the following restrictions.

• Preprocessor is not supported (e.g. search zip files)
• Memory map is not used until --mmap flag is specified
• Adding/Removing file types are not supported. Only default file types are supported (see --type-list)
• .ripgreprc config file is not supported

bat printer v.s. syntect printer

hgrep provides two printers to print match results; bat printer and syntect printer. bat printer is a printer implementation built on top of bat's pretty printer. And syntect printer is our own printer implementation built with syntect library. --printer (or -p) flag can specify the printer to print results.

At first, there was bat printer only. And then syntect printer was implemented for better performance and optimized layout.

Pros of each printers

• bat printer
  • Implementation is battle-tested. It is already used by many users on many platforms and terminals
  • The behavior is compatible with bat command. Its output layout is the same as bat command. It can load bat's assets cache
• syntect printer
  • Performance is much better. 2x to 4x faster (more match results gets better performance)
  • Output layout is optimized for our use cases. For example, a line number at match is highlighted in different color
  • Painting background color (--background) is supported. This is useful when your favorite theme does not fit to your terminal's background color
  • Detection for terminal color support is better. It automatically changes the default theme to 'ansi' when the terminal only supports 16 colors

Currently bat is the default painter (unless bat-printer feature is disabled) because the implementation is not mature yet. But in 0.2 release, changing the default painter to syntect is planned.

Why performance of syntect printer is better?

Syntax highlighting is very CPU heavy task. Many regular expression matchings happen at each line. For accurate syntax highlighting, a highlighter needs to parse the syntax at the beginning of the file. It means that printing a match at the last line of file is much heavier task than printing a match of the first line of the file.

Since syntect printer is designed for calculating syntax highlights per file in parallel, its performance is much better. It's 2x~4x faster than bat printer in some experiments. More match results gets better performance.

In contrast, bat is not designed for multi-threads. It's not possible to share bat::PrettyPrinter instance among threads. It means that printing match results including syntax highlighting must be done in a single thread.

syntect printer sequence	bat printer sequence

Change color theme and layout

Default color theme is Monokai Extended respecting bat command's default. Other theme can be specified via --theme option. To know names of themes, try --list-themes flag.

grep -nH ... | hgrep --theme Nord

And hgrep respects BAT_THEME environment variable.

export BAT_THEME=OneHalfDark

Default layout is 'grid' respecting bat command's default. To print the matches without border lines, --no-grid option is available.

grep -nH ... | hgrep --no-grid

And hgrep respects BAT_STYLE environment variable. When plain or header or numbers is set, hgrep removes border lines.

export BAT_STYLE=numbers

Set default command options

Wrapping hgrep command with shell's alias command works fine for setting default command options.

For example, if you're using Bash, put the following line in your .bash_profile.

# Use syntect-printer and search hidden files by default
alias hgrep='hgrep --printer syntect --hidden'

If you prefer a pager, try the following wrappre function. --term-width propagates the correct width of terminal window.

# Use syntect-printer and less as pager. $COLUMNS corrects terminal window
function hgrep() {
    command hgrep -p syntect --term-width "$COLUMNS" "$@" | less -R
}

Command options

• Common options
  • --min-context NUM (-c): Minimum lines of leading and trailing context surrounding each match. Default value is 5
  • --max-context NUM (-C): Maximum lines of leading and trailing context surrounding each match. Default value is 10
  • --no-grid (-G): Remove border lines for more compact output. --grid flag is an opposite of this flag
  • --tab NUM: Number of spaces for tab character. Set 0 to pass tabs through. Default value is 4
  • --theme THEME: Theme for syntax highlighting. Default value is the same as bat command
  • --list-themes: List all theme names available for --theme option
  • --printer: Printer to print the match results. 'bat' or 'syntect' is available. Default value is 'bat'
  • --term-width: Width (number of characters) of terminal window
• Only for ripgrep feature
  • --no-ignore: Don't respect ignore files (.gitignore, .ignore, etc.)
  • --ignore-case (-i): When this flag is provided, the given patterns will be searched case insensitively
  • --smart-case (-S): Search case insensitively if the pattern is all lowercase. Search case sensitively otherwise
  • --glob GLOB... (-g): Include or exclude files and directories for searching that match the given glob
  • --glob-case-insensitive: Process glob patterns given with the -g/--glob flag case insensitively
  • --fixed-strings (-F): Treat the pattern as a literal string instead of a regular expression
  • --word-regexp (-w): Only show matches surrounded by word boundaries
  • --follow (-L): When this flag is enabled, hgrep will follow symbolic links while traversing directories
  • --multiline (-U): Enable matching across multiple lines
  • --multiline-dotall: Enable "dot all" in your regex pattern, which causes '.' to match newlines when multiline searching is enabled
  • --crlf: about(r"When enabled, hgrep will treat CRLF (\r\n) as a line terminator instead of just \n. This flag is useful on Windows
  • --mmap: Search using memory maps when possible. mmap is disabled by default unlike hgrep
  • --max-count NUM (-m): Limit the number of matching lines per file searched to NUM
  • --max-depth NUM: Limit the depth of directory traversal to NUM levels beyond the paths given
  • --max-filesize NUM: Ignore files larger than NUM in size
  • --line-regexp (-x): Only show matches surrounded by line boundaries. This is equivalent to putting ^...$ around all of the search patterns
  • --pcre2 (-P): When this flag is present, hgrep will use the PCRE2 regex engine instead of its default regex engine
  • --type TYPE (-t): Only search files matching TYPE. This option is repeatable
  • --type-not TYPE (-T): Do not search files matching TYPE. Inverse of --type. This option is repeatable
  • --type-list: Show all supported file types and their corresponding globs
  • --no-wrap: Disable text wrapping. Text wrapping is enabled by default
• Only for syntect-printer feature
  • --background: Paint background colors. This is useful when your favorite theme does not fit to your terminal's background color
• Only for bat-printer feature
  • --custom-assets: Load bat's custom assets from cache. Note that this flag may not work with some version of bat command

See --help for full list of options.

Generate completion scripts

Shell completion script for hgrep command is available. --generate-completion-script option generates completion script and prints it to stdout. Bash, Zsh, Fish, PowerShell, Elvish are supported. See --help for argument of the option.

This is an example to setup the completion script on Zsh.

# Let's say we set comps=~/.zsh/site-functions
hgrep --generate-completion-script zsh > ~/.zsh/site-functions/_hgrep

Alternatives

Some other alternatives instead of using hgrep.

Small ShellScript to combine ripgrep and bat

ripgrep and bat are well-designed tools so they can be used as building parts of small script.

rg -nH ... | while IFS= read -r line; do
  # Parse $line and calculate the range of snippet and highlighted lines
  file=...
  lines=...
  range=...

  # Show matched snippet
  bat -H ${lines} -r ${range} ${file}
done

It works fine but hgrep is more optimized for this usage.

• When the matches are near enough, the lines are printed in one snippet.
• Performance is better than running bat process per matched line.
• hgrep computes efficient context lines based on some heuristics.
• hgrep is available where ShellScript is unavailable (e.g. PowerShell).

Fuzzy finder like fzf with bat preview window

Fuzzy finder like fzf provides a preview window functionality and bat can print the match in the preview window.

grep -nH ... | \
    fzf --preview='bat --pager never --color always -H {2} -r {2}: -p {1}' --delimiter=:

This usage is great when you need the incremental search, but you need to check each preview of matches one by one.

hgrep focuses on surveying all the matches.

Bug reporting

Please make an issue on GitHub. Ensure to describe how to reproduce the bug.

License

hgrep is distributed under the MIT license.