The document contains summaries of common Linux/Unix commands and their functions: - ls lists the contents of a directory. ls -al shows hidden files and more details. - cd changes the current directory. - mkdir creates a new directory. - rm removes (deletes) a file. rm -r removes a directory and all its contents. - cp copies a file or directory. - mv renames or moves a file or directory. - cat outputs the contents of a file. - head/tail outputs the start/end of a file. tail -f outputs adding content to a file.