#file-search #search-query #text-search #line-numbers #line-search #query-string #string-search

bin+lib minigrep_elijahkx

MiniGrep is a Rust-based command-line tool, with a (current) size of 588KB that lets users search files for a given query string and shows matching lines with their line numbers

3 releases

0.1.2 Nov 30, 2023
0.1.1 Nov 30, 2023
0.1.0 Nov 30, 2023

#436 in Text processing

MIT license

182 lines


MiniGrep is a simple command-line utility written in Rust for searching text within files. It provides the capability to search for a specified query string in a given file, displaying lines containing the query along with their line numbers.


Command Syntax

minigrep [query] [file path(s)] [-i]
  • query: The text string to search for within the file.
  • file path(s): The path(s) to the file(s) in which the search will be performed separated by a comma. You can also use "." to search within the current directory.
  • -i (Optional): Performs a case-insensitive search. If provided, the search will ignore the case of the query string.


# Perform a case-sensitive search for the word "hello" in the file "sample.txt"
minigrep hello sample.txt

# Perform a case-sensitive search for the word "hello" in the files "sample.txt" and "sample2.txt"
minigrep hello sample.txt sample2.txt

# Perform a case-sensitive search for the word "hello" in all the files in your current directory.
minigrep hello .

# Perform a case-insensitive search for the word "world" in the file "sample.txt"
minigrep world sample.txt -i

# Redirects the output to a new file. Error messages are not captured in the output file.
minigrep world sample.txt > output.txt 

How It Works

The program uses the following components:

  • run: The main function responsible for executing the search based on the provided configurations.
  • search: Performs a case-sensitive search for the query within the file's contents, returning a vector of tuples containing line numbers and matching lines. The algorithm that is being used is called Boyer Moore
    • Time Complexity: Worst Case O(n * m) - Best Case O(m / n) where m is the length of the query and n is the length of the contents
    • Space Complexity: O(k) where k is the space used for storing the matches.
  • search_case_insensitive: Similar to search, but performs a case-insensitive search.
  • Config: A structure that holds the query, file path, and a boolean flag to indicate whether the search should be case-insensitive.
  • Config::build: Builds the configuration based on the command-line arguments provided.

The program utilizes multiple threads for concurrent file processing to enhance search speed when searching in multiple files. Each file search operation runs in its own thread.

Running Tests

cargo test


The program will display lines containing the query string along with their line numbers within the specified file. If no matching lines are found, it will indicate that the query was not found in the file.

Boyer Moore

Boyer Moore


No runtime deps