README.md

Challenge: Build a Grep Clone

Pygrep

Write a simplified version of grep named pygrep that is executable from the command line and supports basic text searching capabilities.

Your version of pygrep should behave similarly to the standard utility and search all candidate files supplied as arguments.

If no files are specified as arguments to search then pygrep should read and process STDIN.

Upon conclusion of execution if at least one match is made pygrep should exit with a 0 value indicating success; otherwise it should exit with a non-zero value.

Examples of execution from command line:

# searching in specified files
pygrep SEARCH_PATTERN file1.txt file2.txt file3.txt

# searching data streamed in via STDIN
tail -f /path/to/growing/log | pygrep SEARCH_PATTERN

Supported Flags

Your version of pygrep is to support the following command line flags:

• -n prepends the file <line number>: to search matches
• -H prepends the <filename>: to search matches
• -l prints only the filename of files with matches
• -c prints only the count of matching lines
• -v inverts the search to select lines that do not match
• -q quiet operation with zero output so that only the exit code is returned

Some of the flags conflict with each other in their behavior (e.g. -n and -l are mutually exclusive).

It is at your discretion to determine if such conflicts trigger an error and help message or one option simply supersedes another.