grep -B 4 'fonts' /var/log/apache2/access.log The default value for num is 2.įor example, the command will display the 4 lines “before” the pattern match. Replace num with the number of lines to display. -C num: displays the lines before and after the search term match.Replace num with the number of lines to display -A num: displays the lines after the search term match.

-B num: displays the lines before the search term match.The list below contains the available options: Grep provides several command-line options to control the amount of text surrounding your search term results. var/log/fail2ban.log.1: 00:00:10,103 rver : INFO rollover performed on /var/log/fail2ban.log Grep: Viewing a Search Term’s Context var/log/fail2ban.log: 00:00:17,281 rver : INFO rollover performed on /var/log/fail2ban.log grep 'rollover' /var/log/fail2ban.log /var/log/fail2ban.log.1 When grep searches multiple files, its output displays the location of each file where the search term is found. To search multiple files using grep, separate each filename with a whitespace character. The output returned by most Linux distributions highlights the search term in red. Grep is able to find the configuration named ErrorLog in your Apache configuration file and returns the text as output. # If you do not specify an ErrorLog directive within a # ErrorLog: The location of the error log file. Grep’s syntax uses the following format: grep PATTERN įor example, to find the exact location of your system’s Apache error log file, use grep to search for ErrorLog in the Apache configuration file. For example, you may need to search for specific text in a system log file. Grep is a good tool to use when you need to search for a text pattern in a file. It’s name is short for Global Regular Expression Pattern Grep: Search a Log File for Errors Grep is a Linux utility used to find lines of text in files or input streams using regular expressions. This guide provides an overview of each tool with examples and includes links to guides in our library that go deeper into each tool. AWK is a full-fledged programming language that can process text and perform comparison and arithmetic operations on the extracted text.

Sed can find and modify data, however, its syntax is a bit more complex than grep. Grep is used for finding text patterns in a file and is the simplest of the three. However, each tool differs in complexity and what can be accomplished. Each of these tools can read text files line-by-line and use regular expressions to perform operations on specific parts of the file. Grep, sed, and AWK are all standard Linux tools that are able to process text. The Differences Between Grep, sed, and AWK

Grep examples item in line by index