Still, the command line interface is often inconvenient.
If only there were some way to emulate common graphical user interface features on a text display.
For this reason, it is strongly recommended to spend some extra time writing code that validate user’s input. If the user enters 0 as the divisor, the division operation will be something over 0 (which we know from mathematics that it is an illegal operation).With package includes a fairly comprehensive man page and a large set of sample programs that demonstrate the various dialog boxes it can display. They are used to tell the calling script which button on the dialog box (or alternately, the Esc key) was used to terminate the dialog.After installation on a Debian-based system, these sample programs can be found in the uses standard output to display text on the terminal when it is drawing the dialog box itself. The construct used to do this is somewhat interesting. Interpreted sequences are: %% a literal % %a locale’s abbreviated weekday name (e.g., Sun) %A locale’s full weekday name (e.g., Sunday) %b locale’s abbreviated month name (e.g., Jan) %B locale’s full month name (e.g., January) %c locale’s date and time (e.g., Thu Mar 3 2005) %C century; like %Y, except omit last two digits (e.g., 20) %d day of month (e.g, 01) %D date; same as %m/%d/%y %e day of month, space padded; same as %_d %F full date; same as %Y-%m-%d %g last two digits of year of ISO week number (see %G) %G year of ISO week number (see %V); normally useful only with %V %h same as %b %H hour (00..23) %I hour (01..12) %j day of year (001..366) %k hour ( 0..23) %l hour ( 1..12) %m month (01..12) %M minute (00..59) %n a newline %N nanoseconds (000000000..999999999) %p locale’s equivalent of either AM or PM; blank if not known %P like %p, but lower case %r locale’s 12-hour clock time (e.g., PM) %R 24-hour hour and minute; same as %H:%M %s seconds since 1970-01-01 UTC %S second (00..60) %t a tab %T time; same as %H:%M:%S %u day of week (1..7); 1 is Monday %U week number of year, with Sunday as first day of week (00..53) %V ISO week number, with Monday as first day of week (01..53) %w day of week (0..6); 0 is Sunday %W week number of year, with Monday as first day of week (00..53) %x locale’s date representation (e.g., 12/31/99) %X locale’s time representation (e.g., ) %y last two digits of year (00..99) %Y year %z hhmm numeric timezone (e.g., -0400) %:z hh:mm numeric timezone (e.g., -) %::z hh:mm:ss numeric time zone (e.g., -) %:::z numeric time zone with : to necessary precision (e.g., -04, ) %Z alphabetic time zone abbreviation (e.g., EDT) By default, date pads numeric fields with zeroes. The following optional flags may follow ‘%’: - (hyphen) do not pad the field _ (underscore) pad with spaces 0 (zero) pad with zeros ^ use upper case if possible # use opposite case if possible Hi! I'm a Support Manager at Nucleus Hosting in Belgium, a general web geek, public speaker and podcaster.