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grep

Introduction​

This cheat sheet provides a quick reference for some common grep (Global Regular Expression Print) commands and concepts. grep is a command-line utility used for searching and matching text patterns within files on Unix-like operating systems.

grep Concepts​

Basic Usage​

grep searches for a specified pattern in text files.

  • Search for a pattern in a file:

    grep pattern file

  • Search for a pattern in multiple files:

    grep pattern file1 file2

Regular Expressions​

grep supports regular expressions for advanced pattern matching.

  • Search using a basic regular expression:

    grep -G pattern file

  • Search using an extended regular expression:

    grep -E pattern file

grep can perform case-insensitive searches.

  • Perform a case-insensitive search:
    grep -i pattern file

Invert Match​

grep can invert the match, displaying lines that do not contain the pattern.

  • Display lines that do not contain the pattern:
    grep -v pattern file

Line Numbers​

grep can display line numbers for matched lines.

  • Display line numbers for matched lines:
    grep -n pattern file

grep can perform recursive searches in directories.

  • Recursively search for a pattern in directories:
    grep -r pattern directory

Count Matches​

grep can count the number of matches.

  • Count the number of matches:
    grep -c pattern file

grep Command-Line​

  • Search for a pattern in a file:

    grep pattern file

  • Search for a pattern case-insensitively:

    grep -i pattern file

  • Display line numbers for matched lines:

    grep -n pattern file

  • Recursively search for a pattern in directories:

    grep -r pattern directory

  • Count the number of matches:

    grep -c pattern file

Conclusion​

This cheat sheet covers some common grep (Global Regular Expression Print) commands and concepts. grep is a powerful tool for searching and matching text patterns within files, making it useful for tasks like log analysis and text processing; refer to the official grep documentation for more in-depth information and advanced usage.