Command input to Ubr usually consists of one- or two-character escape sequences, such as ESC-o or ^X-n. Arrow keys also have a meaning. Commands can also be selected from a group of menus, activated by pressing ESC-ESC, through which one can navigate using the arrow keys (also the Emacs equivalents ^F, ^B, ^P and ^N). Press Return to select a command; press ^C or ESC-ESC (again) to cancel menu selection mode. All menu items have shortcuts which are displayed next to the menu items; this description only mentions the shortcuts because these are what you'll normally use.
Ubr displays one or more directory listings (very much like the output of ls(1)), each in its own window. A window is really just a segment of the screen; a window has a title line, showing the name of the directory displayed in the window, centered in dashes. At any moment there is a current window, whose title line is shown in inverse video. The directory displayed in the current window is used as the initial working directory, also known as current directory, for all shell commands issued; the term current directory therefore can be used without confusion. There are a number of commands that merely affect which window is current: ^X-n makes the next window on the screen the current window, ^X-p makes the previous window current, ^X-d or ESC-k closes (deletes) the current window. when all windows are closed, ubr quits; ESC-q or ^C can be used to quit immediately.
In each directory window, there is a selection which may be any subset (including the empty set) of the files displayed in the window. The names of selected files are displayed in inverse video. The following commands affect what files are selected in the current window: up-arrow (also ^P) and down-arrow (also ^N) move the selection one line up or down, if possible. ESC-a selects all files in the window. ESC-s prompts for a file name pattern like the ones used by sh(1) and selects all file names in the current window matching that pattern. ^G or ESC-^G only works on HP 2621 terminals (and even then only if you use a beefed-up termcap file). It selects the file currently at the cursor (which is movable by using the arrow keys without pressing the shift key at the same time). On a BLIT, using Sape's tty driver (or mine), you may be able to use mouse clicks to select files.
Besides the selection, which is rather volatile, there is a more permanent marking of files, indicated by a `!' before the file name. These marks can be set or cleared by selecting a file and pressing ESC-f (flip marks). If more than one file is selected, the effect of ESC-f depends on the mark of the first selected file: if set, all marks of selected files are cleared, if clear, all marks are set. The marks are used for deleting, moving and copying files.
ESC-o attempts to open all selected files as subdirectories. If a non-directory is selected, an error message is issued. ESC-O (type ESC-shift-letter Oh) prompts for a pathname of a directory and displays its contents in a window.
ESC-/ (re-read directory contents) is a command which is sometimes necessary after a background job or another user has changed a directory's contents. It reads the directory's contents and conpares it with the window contents; files that have been deleted are deleted from the window, new files are added (and selected!), and the status information for other files is updated if it has changed.
The commands ESC-m, ESC-l and ESC-c can move, link and copy files between directories. They take all marked files in other windows and respectively move, link or copy them to the current directory, where they are made the curernt selection. ESC-d deletes all marked files from the current directory. Note that to delete a file, three actions are necessary: select it, mark it and press ESC-d, so you have a reasonable protection against mistakes. (Also, files are never really deleted but just given a new name that begins with a `,'; such files are removed automatically after a few days, and are not seen by ubr.) ESC-r requires that a single file is selected; it prompts for a new name and the file is given that new name (if there are no conflicts). ESC-n prompts for a name and creates a new, empty subdirectory with that name. The new subdirectory is selected but not opened.
ESC-; prompts for a shell command and executes the command in the current directory, with the files currently selected (if any) as parameters. ESC-! prompts for a shell commands and executes it in the current directory; it does not explicitly pass it the selected files, but the shell variables $1, $2, ... (together referred as $* or ``$@'') contain the selected files names. ESC-$ starts an interactive subshell in the current directory. ESC-e edits the selected files using the editor set in the environment variable $EDITOR (default vi). ESC-p pages the selected files using the pager set in the environment variable $PAGER (default more).