grep:tldr:e697e

The command grep --extended-regexp --ignore-case "${search_pattern}" ${filename} is used to search for a specific pattern or regular expression within a given file.

Here's a breakdown of the command:

• grep: The command itself, which stands for "global regular expression print." It searches for patterns in files and outputs the lines that match those patterns.
• --extended-regexp or -E: This option enables extended regular expressions. It allows you to use more powerful regular expressions with additional functionality.
• --ignore-case or -i: This option tells grep to ignore the case sensitivity of the pattern. It will match patterns regardless of whether they are uppercase, lowercase, or a mix of both.
• "${search_pattern}": Placeholder for the pattern or regular expression you want to search for. Replace ${search_pattern} with the actual pattern you want to find. Make sure to enclose the pattern within double quotes.
• ${filename}: Placeholder for the name of the file or files you want to search within. Replace ${filename} with the actual name of the file or multiple filenames separated by spaces.

When you run this command, grep will search for the specified pattern in the given file(s). If it finds any lines that match the pattern, it will output those lines to the terminal. The --extended-regexp option enables you to use more advanced regular expressions, while --ignore-case makes the search case-insensitive.