33.5. "Colorizing" Scripts
The ANSI [1] escape sequences set screen attributes, such as bold text, and color of foreground and background. DOS batch files commonly used ANSI escape codes for color output, and so can Bash scripts.
Example 33-11. A "colorized" address database
1 #!/bin/bash 2 # ex30a.sh: "Colorized" version of ex30.sh. 3 # Crude address database 4 5 6 clear # Clear the screen. 7 8 echo -n " " 9 echo -e '\E[37;44m'"\033[1mContact List\033[0m" 10 # White on blue background 11 echo; echo 12 echo -e "\033[1mChoose one of the following persons:\033[0m" 13 # Bold 14 tput sgr0 15 echo "(Enter only the first letter of name.)" 16 echo 17 echo -en '\E[47;34m'"\033[1mE\033[0m" # Blue 18 tput sgr0 # Reset colors to "normal." 19 echo "vans, Roland" # "[E]vans, Roland" 20 echo -en '\E[47;35m'"\033[1mJ\033[0m" # Magenta 21 tput sgr0 22 echo "ones, Mildred" 23 echo -en '\E[47;32m'"\033[1mS\033[0m" # Green 24 tput sgr0 25 echo "mith, Julie" 26 echo -en '\E[47;31m'"\033[1mZ\033[0m" # Red 27 tput sgr0 28 echo "ane, Morris" 29 echo 30 31 read person 32 33 case "$person" in 34 # Note variable is quoted. 35 36 "E" | "e" ) 37 # Accept upper or lowercase input. 38 echo 39 echo "Roland Evans" 40 echo "4321 Floppy Dr." 41 echo "Hardscrabble, CO 80753" 42 echo "(303) 734-9874" 43 echo "(303) 734-9892 fax" 44 echo "revans@zzy.net" 45 echo "Business partner & old friend" 46 ;; 47 48 "J" | "j" ) 49 echo 50 echo "Mildred Jones" 51 echo "249 E. 7th St., Apt. 19" 52 echo "New York, NY 10009" 53 echo "(212) 533-2814" 54 echo "(212) 533-9972 fax" 55 echo "milliej@loisaida.com" 56 echo "Girlfriend" 57 echo "Birthday: Feb. 11" 58 ;; 59 60 # Add info for Smith & Zane later. 61 62 * ) 63 # Default option. 64 # Empty input (hitting RETURN) fits here, too. 65 echo 66 echo "Not yet in database." 67 ;; 68 69 esac 70 71 tput sgr0 # Reset colors to "normal." 72 73 echo 74 75 exit 0 |
Example 33-12. Drawing a box
1 #!/bin/bash
2 # Draw-box.sh: Drawing a box using ASCII characters.
3
4 # Script by Stefano Palmeri, with minor editing by document author.
5 # Used in the "ABS Guide" with permission.
6
7
8 ######################################################################
9 ### draw_box function doc ###
10
11 # The "draw_box" function lets the user
12 #+ draw a box into a terminal.
13 #
14 # Usage: draw_box ROW COLUMN HEIGHT WIDTH [COLOR]
15 # ROW and COLUMN represent the position
16 #+ of the upper left angle of the box you're going to draw.
17 # ROW and COLUMN must be greater than 0
18 #+ and less than current terminal dimension.
19 # HEIGHT is the number of rows of the box, and must be > 0.
20 # HEIGHT + ROW must be <= than current terminal height.
21 # WIDTH is the number of columns of the box and must be > 0.
22 # WIDTH + COLUMN must be <= than current terminal width.
23 #
24 # E.g.: If your terminal dimension is 20x80,
25 # draw_box 2 3 10 45 is good
26 # draw_box 2 3 19 45 has bad HEIGHT value (19+2 > 20)
27 # draw_box 2 3 18 78 has bad WIDTH value (78+3 > 80)
28 #
29 # COLOR is the color of the box frame.
30 # This is the 5th argument and is optional.
31 # 0=black 1=red 2=green 3=tan 4=blue 5=purple 6=cyan 7=white.
32 # If you pass the function bad arguments,
33 #+ it will just exit with code 65,
34 #+ and no messages will be printed on stderr.
35 #
36 # Clear the terminal before you start to draw a box.
37 # The clear command is not contained within the function.
38 # This allows the user to draw multiple boxes, even overlapping ones.
39
40 ### end of draw_box function doc ###
41 ######################################################################
42
43 draw_box(){
44
45 #=============#
46 HORZ="-"
47 VERT="|"
48 CORNER_CHAR="+"
49
50 MINARGS=4
51 E_BADARGS=65
52 #=============#
53
54
55 if [ $# -lt "$MINARGS" ]; then # If args are less than 4, exit.
56 exit $E_BADARGS
57 fi
58
59 # Looking for non digit chars in arguments.
60 # Probably it could be done better (exercise for the reader?).
61 if echo $@ | tr -d [:blank:] | tr -d [:digit:] | grep . &> /dev/null; then
62 exit $E_BADARGS
63 fi
64
65 BOX_HEIGHT=`expr $3 - 1` # -1 correction needed because angle char "+" is
66 BOX_WIDTH=`expr $4 - 1` #+ a part of both box height and width.
67 T_ROWS=`tput lines` # Define current terminal dimension
68 T_COLS=`tput cols` #+ in rows and columns.
69
70 if [ $1 -lt 1 ] || [ $1 -gt $T_ROWS ]; then # Start checking if arguments
71 exit $E_BADARGS #+ are correct.
72 fi
73 if [ $2 -lt 1 ] || [ $2 -gt $T_COLS ]; then
74 exit $E_BADARGS
75 fi
76 if [ `expr $1 + $BOX_HEIGHT + 1` -gt $T_ROWS ]; then
77 exit $E_BADARGS
78 fi
79 if [ `expr $2 + $BOX_WIDTH + 1` -gt $T_COLS ]; then
80 exit $E_BADARGS
81 fi
82 if [ $3 -lt 1 ] || [ $4 -lt 1 ]; then
83 exit $E_BADARGS
84 fi # End checking arguments.
85
86 plot_char(){ # Function within a function.
87 echo -e "\E[${1};${2}H"$3
88 }
89
90 echo -ne "\E[3${5}m" # Set box frame color, if defined.
91
92 # start drawing the box
93
94 count=1 # Draw vertical lines using
95 for (( r=$1; count<=$BOX_HEIGHT; r++)); do #+ plot_char function.
96 plot_char $r $2 $VERT
97 let count=count+1
98 done
99
100 count=1
101 c=`expr $2 + $BOX_WIDTH`
102 for (( r=$1; count<=$BOX_HEIGHT; r++)); do
103 plot_char $r $c $VERT
104 let count=count+1
105 done
106
107 count=1 # Draw horizontal lines using
108 for (( c=$2; count<=$BOX_WIDTH; c++)); do #+ plot_char function.
109 plot_char $1 $c $HORZ
110 let count=count+1
111 done
112
113 count=1
114 r=`expr $1 + $BOX_HEIGHT`
115 for (( c=$2; count<=$BOX_WIDTH; c++)); do
116 plot_char $r $c $HORZ
117 let count=count+1
118 done
119
120 plot_char $1 $2 $CORNER_CHAR # Draw box angles.
121 plot_char $1 `expr $2 + $BOX_WIDTH` +
122 plot_char `expr $1 + $BOX_HEIGHT` $2 +
123 plot_char `expr $1 + $BOX_HEIGHT` `expr $2 + $BOX_WIDTH` +
124
125 echo -ne "\E[0m" # Restore old colors.
126
127 P_ROWS=`expr $T_ROWS - 1` # Put the prompt at bottom of the terminal.
128
129 echo -e "\E[${P_ROWS};1H"
130 }
131
132
133 # Now, let's try drawing a box.
134 clear # Clear the terminal.
135 R=2 # Row
136 C=3 # Column
137 H=10 # Height
138 W=45 # Width
139 col=1 # Color (red)
140 draw_box $R $C $H $W $col # Draw the box.
141
142 exit 0
143
144 # Exercise:
145 # --------
146 # Add the option of printing text within the drawn box. |
The simplest, and perhaps most useful ANSI escape sequence is bold text, \033[1m ... \033[0m. The \033 represents an escape, the "[1" turns on the bold attribute, while the "[0" switches it off. The "m" terminates each term of the escape sequence.
bash$ echo -e "\033[1mThis is bold text.\033[0m" |
A similar escape sequence switches on the underline attribute (on an rxvt and an aterm).
bash$ echo -e "\033[4mThis is underlined text.\033[0m" |
 | With an echo, the -e option enables the escape sequences. |
Other escape sequences change the text and/or background color.
bash$ echo -e '\E[34;47mThis prints in blue.'; tput sgr0 bash$ echo -e '\E[33;44m'"yellow text on blue background"; tput sgr0 bash$ echo -e '\E[1;33;44m'"BOLD yellow text on blue background"; tput sgr0 |
| It's usually advisable to set the bold attribute for light-colored foreground text. |
The tput sgr0 restores the terminal settings to normal. Omitting this lets all subsequent output from that particular terminal remain blue.
| Since tput sgr0 fails to restore terminal settings under certain circumstances, echo -ne \E[0m may be a better choice. |
Use the following template for writing colored text on a colored background. echo -e '\E[COLOR1;COLOR2mSome text goes here.' The "\E[" begins the escape sequence. The semicolon-separated numbers "COLOR1" and "COLOR2" specify a foreground and a background color, according to the table below. (The order of the numbers does not matter, since the foreground and background numbers fall in non-overlapping ranges.) The "m" terminates the escape sequence, and the text begins immediately after that. Note also that single quotes enclose the remainder of the command sequence following the echo -e. |
The numbers in the following table work for an rxvt terminal. Results may vary for other terminal emulators.
Table 33-1. Numbers representing colors in Escape Sequences
| Color | Foreground | Background |
|---|---|---|
| black | 30 | 40 |
| red | 31 | 41 |
| green | 32 | 42 |
| yellow | 33 | 43 |
| blue | 34 | 44 |
| magenta | 35 | 45 |
| cyan | 36 | 46 |
| white | 37 | 47 |
Example 33-13. Echoing colored text
1 #!/bin/bash
2 # color-echo.sh: Echoing text messages in color.
3
4 # Modify this script for your own purposes.
5 # It's easier than hand-coding color.
6
7 black='\E[30;47m'
8 red='\E[31;47m'
9 green='\E[32;47m'
10 yellow='\E[33;47m'
11 blue='\E[34;47m'
12 magenta='\E[35;47m'
13 cyan='\E[36;47m'
14 white='\E[37;47m'
15
16
17 alias Reset="tput sgr0" # Reset text attributes to normal
18 #+ without clearing screen.
19
20
21 cecho () # Color-echo.
22 # Argument $1 = message
23 # Argument $2 = color
24 {
25 local default_msg="No message passed."
26 # Doesn't really need to be a local variable.
27
28 message=${1:-$default_msg} # Defaults to default message.
29 color=${2:-$black} # Defaults to black, if not specified.
30
31 echo -e "$color"
32 echo "$message"
33 Reset # Reset to normal.
34
35 return
36 }
37
38
39 # Now, let's try it out.
40 # ----------------------------------------------------
41 cecho "Feeling blue..." $blue
42 cecho "Magenta looks more like purple." $magenta
43 cecho "Green with envy." $green
44 cecho "Seeing red?" $red
45 cecho "Cyan, more familiarly known as aqua." $cyan
46 cecho "No color passed (defaults to black)."
47 # Missing $color argument.
48 cecho "\"Empty\" color passed (defaults to black)." ""
49 # Empty $color argument.
50 cecho
51 # Missing $message and $color arguments.
52 cecho "" ""
53 # Empty $message and $color arguments.
54 # ----------------------------------------------------
55
56 echo
57
58 exit 0
59
60 # Exercises:
61 # ---------
62 # 1) Add the "bold" attribute to the 'cecho ()' function.
63 # 2) Add options for colored backgrounds. |
Example 33-14. A "horserace" game
1 #!/bin/bash
2 # horserace.sh: very simple horserace simulation.
3 # Author: Stefano Palmeri
4 # Used with permission.
5
6 ################################################################
7 # Goals of the script:
8 # playing with escape sequences and terminal colors.
9 #
10 # Exercise:
11 # Edit the script to make it run less randomly,
12 #+ set up a fake betting shop . . .
13 # Um . . . um . . . it's starting to remind me of a movie . . .
14 #
15 # The script gives each horse a random handicap.
16 # The odds are calculated upon horse handicap
17 #+ and are expressed in European(?) style.
18 # E.g.: odds=3.75 means that if you bet $1 and win,
19 #+ you receive $3.75.
20 #
21 # The script has been tested with a GNU/Linux OS,
22 #+ using xterm and rxvt, and konsole.
23 # On a machine with an AMD 900 MHz processor,
24 #+ the average race time is 75 seconds.
25 # On faster computers the race time would be lower.
26 # So, if you want more suspense, reset the USLEEP_ARG variable.
27 #
28 # Script by Stefano Palmeri.
29 ################################################################
30
31 E_RUNERR=65
32
33 # Check if md5sum and bc are installed.
34 if ! which bc &> /dev/null; then
35 echo bc is not installed.
36 echo "Can\'t run . . . "
37 exit $E_RUNERR
38 fi
39 if ! which md5sum &> /dev/null; then
40 echo md5sum is not installed.
41 echo "Can\'t run . . . "
42 exit $E_RUNERR
43 fi
44
45 # Set the following variable to slow down script execution.
46 # It will be passed as the argument for usleep (man usleep)
47 #+ and is expressed in microseconds (500000 = half a second).
48 USLEEP_ARG=0
49
50 # Clean up the temp directory, restore terminal cursor and
51 #+ terminal colors -- if script interrupted by Ctl-C.
52 trap 'echo -en "\E[?25h"; echo -en "\E[0m"; stty echo;\
53 tput cup 20 0; rm -fr $HORSE_RACE_TMP_DIR' TERM EXIT
54 # See the chapter on debugging for an explanation of 'trap.'
55
56 # Set a unique (paranoid) name for the temp directory the script needs.
57 HORSE_RACE_TMP_DIR=$HOME/.horserace-`date +%s`-`head -c10 /dev/urandom | md5sum | head -c30`
58
59 # Create the temp directory and move right in.
60 mkdir $HORSE_RACE_TMP_DIR
61 cd $HORSE_RACE_TMP_DIR
62
63
64 # This function moves the cursor to line $1 column $2 and then prints $3.
65 # E.g.: "move_and_echo 5 10 linux" is equivalent to
66 #+ "tput cup 4 9; echo linux", but with one command instead of two.
67 # Note: "tput cup" defines 0 0 the upper left angle of the terminal,
68 #+ echo defines 1 1 the upper left angle of the terminal.
69 move_and_echo() {
70 echo -ne "\E[${1};${2}H""$3"
71 }
72
73 # Function to generate a pseudo-random number between 1 and 9.
74 random_1_9 () {
75 head -c10 /dev/urandom | md5sum | tr -d [a-z] | tr -d 0 | cut -c1
76 }
77
78 # Two functions that simulate "movement," when drawing the horses.
79 draw_horse_one() {
80 echo -n " "//$MOVE_HORSE//
81 }
82 draw_horse_two(){
83 echo -n " "\\\\$MOVE_HORSE\\\\
84 }
85
86
87 # Define current terminal dimension.
88 N_COLS=`tput cols`
89 N_LINES=`tput lines`
90
91 # Need at least a 20-LINES X 80-COLUMNS terminal. Check it.
92 if [ $N_COLS -lt 80 ] || [ $N_LINES -lt 20 ]; then
93 echo "`basename $0` needs a 80-cols X 20-lines terminal."
94 echo "Your terminal is ${N_COLS}-cols X ${N_LINES}-lines."
95 exit $E_RUNERR
96 fi
97
98
99 # Start drawing the race field.
100
101 # Need a string of 80 chars. See below.
102 BLANK80=`seq -s "" 100 | head -c80`
103
104 clear
105
106 # Set foreground and background colors to white.
107 echo -ne '\E[37;47m'
108
109 # Move the cursor on the upper left angle of the terminal.
110 tput cup 0 0
111
112 # Draw six white lines.
113 for n in `seq 5`; do
114 echo $BLANK80 # Use the 80 chars string to colorize the terminal.
115 done
116
117 # Sets foreground color to black.
118 echo -ne '\E[30m'
119
120 move_and_echo 3 1 "START 1"
121 move_and_echo 3 75 FINISH
122 move_and_echo 1 5 "|"
123 move_and_echo 1 80 "|"
124 move_and_echo 2 5 "|"
125 move_and_echo 2 80 "|"
126 move_and_echo 4 5 "| 2"
127 move_and_echo 4 80 "|"
128 move_and_echo 5 5 "V 3"
129 move_and_echo 5 80 "V"
130
131 # Set foreground color to red.
132 echo -ne '\E[31m'
133
134 # Some ASCII art.
135 move_and_echo 1 8 "..@@@..@@@@@...@@@@@.@...@..@@@@..."
136 move_and_echo 2 8 ".@...@...@.......@...@...@.@......."
137 move_and_echo 3 8 ".@@@@@...@.......@...@@@@@.@@@@...."
138 move_and_echo 4 8 ".@...@...@.......@...@...@.@......."
139 move_and_echo 5 8 ".@...@...@.......@...@...@..@@@@..."
140 move_and_echo 1 43 "@@@@...@@@...@@@@..@@@@..@@@@."
141 move_and_echo 2 43 "@...@.@...@.@.....@.....@....."
142 move_and_echo 3 43 "@@@@..@@@@@.@.....@@@@...@@@.."
143 move_and_echo 4 43 "@..@..@...@.@.....@.........@."
144 move_and_echo 5 43 "@...@.@...@..@@@@..@@@@.@@@@.."
145
146
147 # Set foreground and background colors to green.
148 echo -ne '\E[32;42m'
149
150 # Draw eleven green lines.
151 tput cup 5 0
152 for n in `seq 11`; do
153 echo $BLANK80
154 done
155
156 # Set foreground color to black.
157 echo -ne '\E[30m'
158 tput cup 5 0
159
160 # Draw the fences.
161 echo "++++++++++++++++++++++++++++++++++++++\
162 ++++++++++++++++++++++++++++++++++++++++++"
163
164 tput cup 15 0
165 echo "++++++++++++++++++++++++++++++++++++++\
166 ++++++++++++++++++++++++++++++++++++++++++"
167
168 # Set foreground and background colors to white.
169 echo -ne '\E[37;47m'
170
171 # Draw three white lines.
172 for n in `seq 3`; do
173 echo $BLANK80
174 done
175
176 # Set foreground color to black.
177 echo -ne '\E[30m'
178
179 # Create 9 files to stores handicaps.
180 for n in `seq 10 7 68`; do
181 touch $n
182 done
183
184 # Set the first type of "horse" the script will draw.
185 HORSE_TYPE=2
186
187 # Create position-file and odds-file for every "horse".
188 #+ In these files, store the current position of the horse,
189 #+ the type and the odds.
190 for HN in `seq 9`; do
191 touch horse_${HN}_position
192 touch odds_${HN}
193 echo \-1 > horse_${HN}_position
194 echo $HORSE_TYPE >> horse_${HN}_position
195 # Define a random handicap for horse.
196 HANDICAP=`random_1_9`
197 # Check if the random_1_9 function returned a good value.
198 while ! echo $HANDICAP | grep [1-9] &> /dev/null; do
199 HANDICAP=`random_1_9`
200 done
201 # Define last handicap position for horse.
202 LHP=`expr $HANDICAP \* 7 + 3`
203 for FILE in `seq 10 7 $LHP`; do
204 echo $HN >> $FILE
205 done
206
207 # Calculate odds.
208 case $HANDICAP in
209 1) ODDS=`echo $HANDICAP \* 0.25 + 1.25 | bc`
210 echo $ODDS > odds_${HN}
211 ;;
212 2 | 3) ODDS=`echo $HANDICAP \* 0.40 + 1.25 | bc`
213 echo $ODDS > odds_${HN}
214 ;;
215 4 | 5 | 6) ODDS=`echo $HANDICAP \* 0.55 + 1.25 | bc`
216 echo $ODDS > odds_${HN}
217 ;;
218 7 | 8) ODDS=`echo $HANDICAP \* 0.75 + 1.25 | bc`
219 echo $ODDS > odds_${HN}
220 ;;
221 9) ODDS=`echo $HANDICAP \* 0.90 + 1.25 | bc`
222 echo $ODDS > odds_${HN}
223 esac
224
225
226 done
227
228
229 # Print odds.
230 print_odds() {
231 tput cup 6 0
232 echo -ne '\E[30;42m'
233 for HN in `seq 9`; do
234 echo "#$HN odds->" `cat odds_${HN}`
235 done
236 }
237
238 # Draw the horses at starting line.
239 draw_horses() {
240 tput cup 6 0
241 echo -ne '\E[30;42m'
242 for HN in `seq 9`; do
243 echo /\\$HN/\\" "
244 done
245 }
246
247 print_odds
248
249 echo -ne '\E[47m'
250 # Wait for a enter key press to start the race.
251 # The escape sequence '\E[?25l' disables the cursor.
252 tput cup 17 0
253 echo -e '\E[?25l'Press [enter] key to start the race...
254 read -s
255
256 # Disable normal echoing in the terminal.
257 # This avoids key presses that might "contaminate" the screen
258 #+ during the race.
259 stty -echo
260
261 # --------------------------------------------------------
262 # Start the race.
263
264 draw_horses
265 echo -ne '\E[37;47m'
266 move_and_echo 18 1 $BLANK80
267 echo -ne '\E[30m'
268 move_and_echo 18 1 Starting...
269 sleep 1
270
271 # Set the column of the finish line.
272 WINNING_POS=74
273
274 # Define the time the race started.
275 START_TIME=`date +%s`
276
277 # COL variable needed by following "while" construct.
278 COL=0
279
280 while [ $COL -lt $WINNING_POS ]; do
281
282 MOVE_HORSE=0
283
284 # Check if the random_1_9 function has returned a good value.
285 while ! echo $MOVE_HORSE | grep [1-9] &> /dev/null; do
286 MOVE_HORSE=`random_1_9`
287 done
288
289 # Define old type and position of the "randomized horse".
290 HORSE_TYPE=`cat horse_${MOVE_HORSE}_position | tail -1`
291 COL=$(expr `cat horse_${MOVE_HORSE}_position | head -1`)
292
293 ADD_POS=1
294 # Check if the current position is an handicap position.
295 if seq 10 7 68 | grep -w $COL &> /dev/null; then
296 if grep -w $MOVE_HORSE $COL &> /dev/null; then
297 ADD_POS=0
298 grep -v -w $MOVE_HORSE $COL > ${COL}_new
299 rm -f $COL
300 mv -f ${COL}_new $COL
301 else ADD_POS=1
302 fi
303 else ADD_POS=1
304 fi
305 COL=`expr $COL + $ADD_POS`
306 echo $COL > horse_${MOVE_HORSE}_position # Store new position.
307
308 # Choose the type of horse to draw.
309 case $HORSE_TYPE in
310 1) HORSE_TYPE=2; DRAW_HORSE=draw_horse_two
311 ;;
312 2) HORSE_TYPE=1; DRAW_HORSE=draw_horse_one
313 esac
314 echo $HORSE_TYPE >> horse_${MOVE_HORSE}_position # Store current type.
315
316 # Set foreground color to black and background to green.
317 echo -ne '\E[30;42m'
318
319 # Move the cursor to new horse position.
320 tput cup `expr $MOVE_HORSE + 5` `cat horse_${MOVE_HORSE}_position | head -1`
321
322 # Draw the horse.
323 $DRAW_HORSE
324 usleep $USLEEP_ARG
325
326 # When all horses have gone beyond field line 15, reprint odds.
327 touch fieldline15
328 if [ $COL = 15 ]; then
329 echo $MOVE_HORSE >> fieldline15
330 fi
331 if [ `wc -l fieldline15 | cut -f1 -d " "` = 9 ]; then
332 print_odds
333 : > fieldline15
334 fi
335
336 # Define the leading horse.
337 HIGHEST_POS=`cat *position | sort -n | tail -1`
338
339 # Set background color to white.
340 echo -ne '\E[47m'
341 tput cup 17 0
342 echo -n Current leader: `grep -w $HIGHEST_POS *position | cut -c7`" "
343
344 done
345
346 # Define the time the race finished.
347 FINISH_TIME=`date +%s`
348
349 # Set background color to green and enable blinking text.
350 echo -ne '\E[30;42m'
351 echo -en '\E[5m'
352
353 # Make the winning horse blink.
354 tput cup `expr $MOVE_HORSE + 5` `cat horse_${MOVE_HORSE}_position | head -1`
355 $DRAW_HORSE
356
357 # Disable blinking text.
358 echo -en '\E[25m'
359
360 # Set foreground and background color to white.
361 echo -ne '\E[37;47m'
362 move_and_echo 18 1 $BLANK80
363
364 # Set foreground color to black.
365 echo -ne '\E[30m'
366
367 # Make winner blink.
368 tput cup 17 0
369 echo -e "\E[5mWINNER: $MOVE_HORSE\E[25m"" Odds: `cat odds_${MOVE_HORSE}`"\
370 " Race time: `expr $FINISH_TIME - $START_TIME` secs"
371
372 # Restore cursor and old colors.
373 echo -en "\E[?25h"
374 echo -en "\E[0m"
375
376 # Restore echoing.
377 stty echo
378
379 # Remove race temp directory.
380 rm -rf $HORSE_RACE_TMP_DIR
381
382 tput cup 19 0
383
384 exit 0 |
See also Example A-22.
 | There is, however, a major problem with all this. ANSI escape sequences are emphatically non-portable. What works fine on some terminal emulators (or the console) may work differently, or not at all, on others. A "colorized" script that looks stunning on the script author's machine may produce unreadable output on someone else's. This greatly compromises the usefulness of "colorizing" scripts, and possibly relegates this technique to the status of a gimmick or even a "toy". |
Moshe Jacobson's color utility (http://runslinux.net/projects.html#color) considerably simplifies using ANSI escape sequences. It substitutes a clean and logical syntax for the clumsy constructs just discussed.
Henry/teikedvl has likewise created a utility (http://scriptechocolor.sourceforge.net/) to simplify creation of colorized scripts.