Terminal control/Unicode output

Terminal control/Unicode output is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The task is to check that the terminal supports Unicode output, before outputting a Unicode character. If the terminal supports Unicode, then the terminal should output a Unicode delta (U+25b3). If the terminal does not support Unicode, then an appropriate error should be raised.

UNIX Shell

<lang sh>if

 awk '
    BEGIN {
      if (ENVIRON["LANG"] ~ "UTF")
        exit 0    # exit ok
      exit 255    # exit false
    }'

then

 # This terminal supports Unicode
 printf "\u25b3"    # Requires a Unicode compatible printf

else

 echo "HW65001 This program requires a Unicode compatible terminal" >&2
 exit 252    # Incompatible hardware

fi</lang>