What option with grep shows all lines in a file that do not match a given string?

The choice of using -v with grep is the correct approach for displaying all lines in a file that do not match a specified string. The -v option tells grep to invert the match, meaning it will exclude lines that contain the pattern you are searching for. Instead, it will show only the lines that do not have that pattern.

For example, if you run a command like grep -v "pattern" filename.txt, it will output every line from filename.txt that does not contain the word "pattern." This feature is particularly useful when you want to filter out specific information and focus on the remaining content of a file.

Understanding how to use the -v option effectively allows users to conduct more nuanced searches and data manipulations within files, which is a fundamental skill in Unix/Linux environments for text processing and analysis.