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COMPUTER BITS BY JENNIFER BONNITCHA Colouring your PC world Following on from last month's article, this month we have more adventures with the PROMPT command to set screen colours and customise your display. The DOS command PROMPT lets you change the dull, boring C> to almost anything you like - you can change the colours, location and the information shown at the prompt. PROMPT changes video attributes only. You can create a wide range of output possibilities by using symbolic replacements called metasymbols. You must precede each character with a dollar sign ($) and note that unlike the ANSI sequences, PROMPT is not case sensitive. Table 1 shows the details. PROMPT $P$G is probably the most popular way to customise the system prompt. With this sequence, you can see instantly the current drive and path, eg, C: \ WP51 \DATA>. PROMPT also lets you add instructions: any number of times through the keyboard or executed from within a batch file. Display screen attributes This command displays on one line the drive and path ($P), a space, the date ($D), a space and the time ($T). On the second line ($_), it displays the message What's Up Doc? and the greater than sign ($G). The Set Graphics Rendition command ESC[#; ... ;#m sets the screen display attributes. The command sequence may contain one or more of the parameters listed below. You should, however, check your DOS manual for any additions or alterations from your computer's manufacturer. Most monitors today support graphic functions, therefore you can call the graphic functions from the following list. The functions remain until the next occurence of a Set Graphics Rendition escape sequence. Setting and adjusting the screen colours and background intensity of the monitor is quite useful. ANSI uses the same colour codes for both the foreground and background. You start with the digit 3 for foreground colours and the digit 4 for background colours . In addition, you can specify several attributes such as high intensity (bold), reverse video etc. Escape sequences O All attributes off As noted briefly last month, you can send escape sequences to ANSI.SYS using the PROMPT command $E which represents the escape character. There are several advantages when you use PROMPT, because you can easily change the instructions you send and the commands can be used 1 High intensity display on (ie, bright) 2 Normal intensity display on 4 Underline (monochrome monitor only) 5 Blink on 7 Reverse video on 8 Concealed on, no display (invisible) PROMPT $P $D $T$_What's Up Doc?$G 76 SILICON CHIP Foreground 30 Black 31 Red 32 Green 33 Brown 34 Blue 35 Magenta (purple) 36 Cyan (light blue) 37 White Background 40 Black 41 Red 42 Green 43 Brown 44 Blue 45 Magenta 46 Cyan 47 White Note that turning on high intensity brightens the foreground colours only, with the exception that black turns to grey and brown to yellow. You can set one or more numerical values. Make sure you use only the semicolon to delimit (separate) the parameters in the escape sequence. Using the above table, you could set the following: ESC[37m - Foreground colour to white ESC[44m - Background colour to blue ESC[37;44m - Foreground and background colours simultaneously ESC[1;37;44m - Foreground to bright (1) white (37) on a blue (44) background It's good practice to use the three parameters to specify colour changes. Keep the parameters together rather than issuing one by itself. Note that changing the foreground colour doesn't turn the intensity on or off you need to do that with the O or 1 parameter - and that parameter O also clears the colours to their default value of white on black. You could build a set of simple batch files to show different coloured prompts for directories or drives so you can see at a glance what's going on, such as: <at>ECHO OFF C: PROMPT $E[36m$P$G TABLE 1 SPECIFY THIS CHARACTER $ b d e g I n p t V TO GET THIS PROMPT The $ character The I character The current date Escape character (ASCII code 1b hex, 27 decimal) The > character The < character The default drive The working directory of the default drive The current time The DOS version number Carriage return, linefeed sequence. Note that this is the underscore character. This specifies cyan as the foreground colour with the current drive and path. <at>ECHO OFF C: CD\DBASE PROMPT $E[1;37;45m$P$G This changes to the dBASE subdirectory and alters the prompt to show bright (1) white (37) on a magenta background (45). You may like to set your prompt to a different colour but have the text you type at the prompt return to normal video mode: PROMPT $E[7m$P$G$e[m Date & time display For a really fancy display, complete with date and time display (which only updates when you press the Enter key): PROMPT $e[s$e[25;56H$e[1;37;45m $t$h$h$h$h$h$h $d$e[0m$e[u$p$g Phew! Take a close look at the above command which need not necessarily be entered in this sequence. You can enter the ANSI comm~nds in any sequence, provided the parameters for each are entered correctly. $e[s Saves the cursor's current position. $e[25;56H Moves the cursor to row 25, column 56 (bottom righthand corner of the screen). $e[1 ;37 ;45m specifies bright white on a magenta background. $t displays the current time. $h$h$h$h$h$h displays the current time as hours and minutes. (space) the space character separates the time from the next parameter. $d displays the current date. $e[0m resets the text to normal. $e[u returns the cursor to its starting position. $p displays the current drive and path information. $g displays the greater than sign (> ). The space in the command is critical to the separation of the time and date display. The space character is treated by the PROMPT command just like any other keyboard character and will appear in the final DOS prompt line. You may need to set your screen colours when you exit a program, so it is worthwhile to include the prompt line in any batch files you may be using. Experiment with the following batch fil e, TEST5.BAT (the IF, GOTO and % statements will be covered in a future article): <at>ECHO OFF CLS IF !NORMAL==!%1 GOTO %1 IF !BRIGHT==!%1 GOTO %1 IF !REVERSE== !%1 GOTO %1 GOTO HELP :NORMAL PROMPT $e[0m$P$G GOTO FINISH :BRIGHT PROMPT $e[0;1m$P$G GOTO FINISH :REVERSE PROMPT $e[0;7m$P$G GOTO FINISH :HELP ECHO THE PROPER FORMAT IS ECHO either TEST5 NORMAL ECHO OR TEST5 BRIGHT ECHO OR TEST5 REVERSE ECHO MAKE SURE YOU TYPE THE REQUIRED ATTRIBUTE IN UPPERCASE GOTO FINISH :END CLS :FINISH If you type the attribute in other than uppercase, the batch file displays the help messages shown above. Naturally, you can include any additional colours as required. It sometimes helps to have the entire screen change to the new colour/ intensity, etc immediately. If you add the ESC [2J sequence to the end of any command, the entire screen is cleared and your choices are in effect. 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BU205 TOROIDAL TRANSFORMER (Cnr Kippax St. opp. Central Station & Dental Hospital) 640x200 640x350 640x350 640x480 640x480 320x200 $19.95each PROJECT CASE In . two parts amd measures 250(W) x 130(0) X 110(H), screw mounting holes . Has many uses. ONLY $14.95 2 3 4 5 6 7 DOS 4.x only 14 15 FUNCTION 40x25 black and white 40x25 colour 80x25 black and white 80x25 colou r 320x200 colour 320x'200 black and white 640x200 black and white Wraps at the end of each line ,. ~ ~ 0M . SHOP HOURS: MON - FRI SAT 9.00am- 5.30pm 9.30am-12.00pm I The ESC[=lh command activates the 40 character by 25 line black and white text mode. Another handy feature is the function ESC[#l mentioned above, which disables character wrap. When character wrap is on (which by default it is), any lines containing more than 80 characters "wrap" to the next line. When wrap is disabled, only 80 characte~s display so you can view any file using the DOS command TYPE and not be distracted by the remaining information displaying on the subsequent line. Restore character wrap using ESC[=7h, as described above. Note that the type of monitor you own will determine the success or otherwise of the various commands described this month. This is particularly true if you have a monochrome (green/black, amber/black etc) monitor. Next month, we will discuss using ANSI to control keyboard reassignment. Happy colouring! SC