A$ = CHR$(0) + CHR$(1) + CHR$(254) + CHR$(255) : REM assignment
      B$ = A$                                        : REM clone / copy
      IF A$ = B$ THEN PRINT "Strings are equal"      : REM comparison
      IF A$ = "" THEN PRINT "String is empty"        : REM Check if empty
      A$ += CHR$(128)                                : REM Append a byte
      S$ = MID$(A$, S%, L%)                          : REM Extract a substring
      C$ = A$ + B$                                   : REM Join strings

      REM To replace every occurrence of a byte:
      old$ = CHR$(1)
      new$ = CHR$(5)
      REPEAT
        I% = INSTR(A$, old$)
        IF I% MID$(A$, I%, 1) = new$
      UNTIL I% = 0