How to use the command zegrep (with examples)

zegrep is a command that allows you to search for extended regular expression patterns in compressed files using egrep. It supports various options such as case-sensitive or case-insensitive search, matching only lines that do not match a pattern, printing file names and line numbers for each match, printing only the matched text, and recursively searching files within a compressed file.

Use case 1: Search for extended regular expressions in a compressed file (case-sensitive)

Code:

zegrep "search_pattern" path/to/file

Motivation: This use case is useful when you want to search for specific extended regular expressions in a compressed file, while considering the case sensitivity of the search.

Explanation:

• zegrep: This is the command used to search for extended regular expressions in compressed files.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

path/to/file:1: This is a line containing the search_pattern.
path/to/file:5: Another line with the search_pattern.

Use case 2: Search for extended regular expressions in a compressed file (case-insensitive)

Code:

zegrep --ignore-case "search_pattern" path/to/file

Motivation: This use case is helpful when you want to search for extended regular expressions in a compressed file, without considering the case sensitivity of the search.

Explanation:

• --ignore-case: This option tells zegrep to perform a case-insensitive search.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

path/to/file:1: This is a line containing the search_pattern.
path/to/file:3: Another line with the SEARCH_PATTERN.

Use case 3: Search for lines that do not match a pattern

Code:

zegrep --invert-match "search_pattern" path/to/file

Motivation: This use case is useful when you want to find lines in a compressed file that do not match a specific pattern.

Explanation:

• --invert-match: This option tells zegrep to print lines that do not match the specified pattern.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

path/to/file:2: This line does not match the search_pattern.
path/to/file:4: Another line without the search_pattern.

Use case 4: Print file name and line number for each match

Code:

zegrep --with-filename --line-number "search_pattern" path/to/file

Motivation: This use case is helpful when you want to know the file name and line number for each match of a pattern in a compressed file.

Explanation:

• --with-filename: This option tells zegrep to print the file name before each match.
• --line-number: This option tells zegrep to print the line number for each match.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

path/to/file:1: This is a line containing the search_pattern.

Use case 5: Search for lines matching a pattern, printing only the matched text

Code:

zegrep --only-matching "search_pattern" path/to/file

Motivation: This use case is useful when you want to search for a pattern in a compressed file and only need the actual matched text, without the rest of the line.

Explanation:

• --only-matching: This option tells zegrep to print only the matched text, without the rest of the line.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

search_pattern
SEARCH_PATTERN

Use case 6: Recursively search files in a compressed file for a pattern

Code:

zegrep --recursive "search_pattern" path/to/file

Motivation: This use case is helpful when you want to recursively search for a pattern within files contained in a compressed file.

Explanation:

• --recursive: This option tells zegrep to search for the pattern recursively within files.
• "search_pattern": This is the pattern you want to search for in the file.
• path/to/file: This is the path of the compressed file you want to search in.

Example output:

path/to/file:1: This is a line containing the search_pattern.
path/to/file/subfile:3: Another line with the search_pattern.
path/to/file/subfolder/another_file:2: Yet another match for search_pattern.

Conclusion:

The zegrep command provides a convenient way to search for extended regular expression patterns in compressed files. Whether it’s a case-sensitive or case-insensitive search, printing file names and line numbers, matching only the text of a pattern, or recursively searching within files, zegrep offers various options to meet your search requirements.