Build, test, and debug regular expressions
Matches lines beginning with 'ssh' followed by any single character, then captures one or more non-whitespace characters up to the next space. With the multiline flag, it works line-by-line on text. Commonly used to parse SSH logs or command strings, e.g. extracting the token after 'sshd[pid]:' or the user/host after 'ssh ' — effectively grabbing the substring between the first and second space.