The command is used to left justify text. Text is flowed in each line of a paragraph up to a limit set with the -r option in the command line. If no limit is given in the command line, then a default value of 72 characters per line is used. This limit is used to wrap lines during composition, as well as to justify text. The command justifies the text in the paragraph that the cursor is placed on. The command is used to justify the full file. In case that justification is not done correctly, or by mistake, it can be undone by pressing the command immediately after justification has been done.