The xterm 256-color table (set colors in xterm or PuTTY)

nospam@example.com (John) — Sun, 15 Jan 2017 13:28:00 +0000

Updated: 2017-01-15 08:28 (Originally Created: 2015-03-32 19:12)
Updated: 2016-07-15 18:02 (Originally Created: 2015-03-32 19:12)
Updated: 2015-09-26 9:51 (Originally Created: 2015-03-32 19:12)

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Setting background and foreground colors in an xterm terminal

The xterm terminal (and PuTTY) permit you to programmatically set the foreground and background colors of your terminal using VT styled escape sequenced (e.g., vt200). These are region-based, and can be used to change the color on a character-by-character basis. There are a variety of different sequences for setting these colors, but, for now at least, if you want to use PuTTY as well as X-Window you should use the following sequences. These sequences take an index into a table of colors (see The Chart below) defined and specified by xterm.

Set the Background Color

To set the background color by index hand this escape sequence to the terminal:

<esc>[48;5;<c>m

Where <c> is the index (from the chart below) for the color you want to make the background.

You can send the sequence to the terminal with the echo command. Give it the -n option so that it wont echo a new-line at the end of the sequence. Here are some examples:

Set background

echo -n "\033[48;5;16m"
Sets the background to black (index 16 from the chart). Note that \033 is the escape character.
printf "\033[48;5;16m"
Same as the echo statement above, but using the more portable printf command.
printf "\033[48;5;17m"
Sets the background to dim blue for text editing. (index 17 from the chart).

Set the Foreground Color

To set the foreground color by index, use the following escape sequence:

<esc>[38;5;<c>m

Note the '48' has been changed to a '38'. The <c> remains the index from the chart (below) for the color you want to use.

Use the echo command to send the sequence. As always, the -n option is used to prevent echo from sending a new-line at the end of the sequence.

Set foreground

printf "\033[38;5;16m"
Sets the foreground (text color) to black (index 16 from the chart). Again, \033 (octal) = 27 (dec) = Esc
printf "\033[38;5;17m"
Sets the foreground (text) to dim blue. (index 17 from the chart).

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The Most Rationally Formatted Chart

216 regular colors, indexed
That's a lot of factors:
216 factors: 1,2,3,4,6,8,9,12,18,24,27,36,54,72,108,216

Format: 6x36

The first six rows of this table hold the entire range of Blue across the X-axis, and the complete range of Green down the Y-axis. The remaining five, six-line charts are the entire range of RED overlaid onto the first chart. Said another way, each six-line chart represents one data point on the (RED) Z-axis, with X=BLUE, and Y=GREEN. Essentially it is BGR instead of RGB . Both index, and rgb-value orders, are preserved.

b=x, g=y, r=0
016 000000	017 00005f	018 000087	019 0000af	020 0000d7	021 0000ff
022 005f00	023 0005f5f	024 005f87	025 005faf	026 005fd7	027 005fff
028 008700	029 00875f	030 008787	031 0087af	032 0087d7	033 0087ff
034 00af00	035 000af5f	036 00af87	037 00afaf	038 00afd7	039 00afff
040 00d700	041 00d75f	042 00d787	043 00d7af	044 00d7d7	045 00d7ff
046 00ff00	047 000ff5f	048 00ff87	049 00ffaf	050 00ffd7	051 00ffff
b=x, g=y, r=0x5f
052 5f0000	053 5f005f	054 5f0087	055 5f00af	056 5f00d7	057 5f00ff
058 5f5f00	059 5f05f5f	060 5f5f87	061 5f5faf	062 5f5fd7	063 5f5fff
064 5f8700	065 5f875f	066 5f8787	067 5f87af	068 5f87d7	069 5f87ff
070 5faf00	071 5f0af5f	072 5faf87	073 5fafaf	074 5fafd7	075 5fafff
076 5fd700	077 5fd75f	078 5fd787	079 5fd7af	080 5fd7d7	081 5fd7ff
082 5fff00	083 5f0ff5f	084 5fff87	085 5fffaf	086 5fffd7	087 5fffff
b=x, g=y, r=0x87
088 870000	089 87005f	090 870087	091 8700af	092 8700d7	093 8700ff
094 875f00	095 8705f5f	096 875f87	097 875faf	098 875fd7	099 875fff
100 878700	101 87875f	102 878787	103 8787af	104 8787d7	105 8787ff
106 87af00	107 870af5f	108 87af87	109 87afaf	110 87afd7	111 87afff
112 87d700	113 87d75f	114 87d787	115 87d7af	116 87d7d7	117 87d7ff
118 87ff00	119 870ff5f	120 87ff87	121 87ffaf	122 87ffd7	123 87ffff
b=x, g=y, r=0xaf
124 af0000	125 af005f	126 af0087	127 af00af	128 af00d7	129 af00ff
130 af5f00	131 af05f5f	132 af5f87	133 af5faf	134 af5fd7	135 af5fff
136 af8700	137 af875f	138 af8787	139 af87af	140 af87d7	141 af87ff
142 afaf00	143 af0af5f	144 afaf87	145 afafaf	146 afafd7	147 afafff
148 afd700	149 afd75f	150 afd787	151 afd7af	152 afd7d7	153 afd7ff
154 afff00	155 af0ff5f	156 afff87	157 afffaf	158 afffd7	159 afffff
b=x, g=y, r=0xd7
160 d70000	161 d7005f	162 d70087	163 d700af	164 d700d7	165 d700ff
166 d75f00	167 d705f5f	168 d75f87	169 d75faf	170 d75fd7	171 d75fff
172 d78700	173 d7875f	174 d78787	175 d787af	176 d787d7	177 d787ff
178 d7af00	179 d70af5f	180 d7af87	181 d7afaf	182 d7afd7	183 d7afff
184 d7d700	185 d7d75f	186 d7d787	187 d7d7af	188 d7d7d7	189 d7d7ff
190 d7ff00	191 d70ff5f	192 d7ff87	193 d7ffaf	194 d7ffd7	195 d7ffff
b=x, g=y, r=0xff
196 ff0000	197 ff005f	198 ff0087	199 ff00af	200 ff00d7	201 ff00ff
202 ff5f00	203 ff05f5f	204 ff5f87	205 ff5faf	206 ff5fd7	207 ff5fff
208 ff8700	209 ff875f	210 ff8787	211 ff87af	212 ff87d7	213 ff87ff
214 ffaf00	215 ff0af5f	216 ffaf87	217 ffafaf	218 ffafd7	219 ffafff
220 ffd700	221 ffd75f	222 ffd787	223 ffd7af	224 ffd7d7	225 ffd7ff
226 ffff00	227 ff0ff5f	228 ffff87	229 ffffaf	230 ffffd7	231 ffffff

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The Missing Slots

There are 16 missing color-indexes (0-15) at the beginning, and 24 missing color-indexes (232-255) at the end.

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The Original ANSI 8 (16)

The 16 color-indexes missing at the beginning of the above chart hold the generic set of eight colors you see (for example) in ansi, or curses, as named colors. It contains another eight colors which are —sort-of— the same colors repeated, but duller (more dull?).

Note that these already exist in the above chart. The reason you see them repeated again here is because these were preserved in order to be compatible with the old xterm, which only had the first 16 color-indexes. Old software that references these indexes will not be broken. Here's their chart:

000 000000	001 800000	002 008000	003 808000	004 000080	005 800080	006 008080	007 c0c0c0
008 808080	009 ff0000	010 00ff00	011 ffff00	012 0000ff	013 ff00ff	014 00ffff	015 ffffff

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The Extra Gray Scale

The 24 color-indexes missing at the end of the above chart are a set of gray scale colors. I'm not sure what their purpose is. They are slightly different than the grays available in the main chart. Perhaps a continuously indexed gray scale permits some simple math to be used when shading/ray-tracing? Anyway. Here's that chart.

232 080808	233 121212	234 1c1c1c	235 262626	236 303030	237 3a3a3a	238 444444	239 4e4e4e
240 585858	241 626262	242 6c6c6c	243 767676	244 808080	245 8a8a8a	246 949494	247 9e9e9e
248 a8a8a8	249 b2b2b2	250 bcbcbc	251 c6c6c6	252 d0d0d0	253 dadada	254 e4e4e4	255 eeeeee

More about how to set these colors (foreground and background) from applications running in xterm and PuTTY follows. . .

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Terminal Sequences for Setting Colors with RGB designators

There are two different sets of sequences for setting colors using rgb codes. These usually work in X11, but if you intend to use PuTTY to access your server, you should use the index-setting sequences (PuTTY doesn't currently support these rgb sequences). For the time being, at least, using indexes will allow your applications to work consistently along with the xterms in X11. Never hurts to do an echo command from the command line to test if a newer version does.

Using three (rgb) decimal numbers:

This control sequence takes three parameters (r,g,b), which are decimal numbers from 0 .. 255. Each decimal number represents the intensity of its respective color.

To set the background color:
<ESC>[48;2;<r>;<g>;<b>m

echo it from a the command line:
printf "\033[48;2;0;0;100m"
(dark blue)

And from a script:
printf "\033[48;2;$r;$g;${b}m"

To set the foreground color:
<ESC>[38;2;<r>;<g>;<b>m
(change the 48 to 38)

Using an HTML-Entity styled rgb parameter

To set the background:
<ESC>]11;#53186f<BEL>

To echo that:
printf "\033]11;#53186f\007"
(dark purple background)

To set the foreground:
<ESC>]13;#53186f<BEL>
(dark purple text)

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The Coffee Mug Format

format: 12x18

016 000000	017 00005f	018 000087	019 0000af	020 0000d7	021 0000ff	022 005f00	023 0005f5f	024 005f87	025 005f87	026 005fd7	027 005fff
028 008700	029 00875f	030 008787	031 0087af	032 0087d7	033 0087ff	034 00af00	035 000af5f	036 00af87	037 00af87	038 00afd7	039 00afff
040 00d700	041 00d75f	042 00d787	043 00d7af	044 00d7d7	045 00d7ff	046 00ff00	047 000ff5f	048 00ff87	049 00ff87	050 00ffd7	051 00ffff
052 5f0000	053 5f005f	054 5f0087	055 5f00af	056 5f00d7	057 5f00ff	058 5f5f00	059 5f05f5f	060 5f5f87	061 5f5f87	062 5f5fd7	063 5f5fff
064 5f8700	065 5f875f	066 5f8787	067 5f87af	068 5f87d7	069 5f87ff	070 5faf00	071 5f0af5f	072 5faf87	073 5faf87	074 5fafd7	075 5fafff
076 5fd700	077 5fd75f	078 5fd787	079 5fd7af	080 5fd7d7	081 5fd7ff	082 5fff00	083 5f0ff5f	084 5fff87	085 5fff87	086 5fffd7	087 5fffff
088 870000	089 87005f	090 870087	091 8700af	092 8700d7	093 8700ff	094 875f00	095 8705f5f	096 875f87	097 875f87	098 875fd7	099 875fff
100 878700	101 87875f	102 878787	103 8787af	104 8787d7	105 8787ff	106 87af00	107 870af5f	108 87af87	109 87af87	110 87afd7	111 87afff
112 87d700	113 87d75f	114 87d787	115 87d7af	116 87d7d7	117 87d7ff	118 87ff00	119 870ff5f	120 87ff87	121 87ff87	122 87ffd7	123 87ffff
124 af0000	125 af005f	126 af0087	127 af00af	128 af00d7	129 af00ff	130 af5f00	131 af05f5f	132 af5f87	133 af5f87	134 af5fd7	135 af5fff
136 af8700	137 af875f	138 af8787	139 af87af	140 af87d7	141 af87ff	142 afaf00	143 af0af5f	144 afaf87	145 afaf87	146 afafd7	147 afafff
148 afd700	149 afd75f	150 afd787	151 afd7af	152 afd7d7	153 afd7ff	154 afff00	155 af0ff5f	156 afff87	157 afff87	158 afffd7	159 afffff
160 d70000	161 d7005f	162 d70087	163 d700af	164 d700d7	165 d700ff	166 d75f00	167 d705f5f	168 d75f87	169 d75f87	170 d75fd7	171 d75fff
172 d78700	173 d7875f	174 d78787	175 d787af	176 d787d7	177 d787ff	178 d7af00	179 d70af5f	180 d7af87	181 d7af87	182 d7afd7	183 d7afff
184 d7d700	185 d7d75f	186 d7d787	187 d7d7af	188 d7d7d7	189 d7d7ff	190 d7ff00	191 d70ff5f	192 d7ff87	193 d7ff87	194 d7ffd7	195 d7ffff
196 ff0000	197 ff005f	198 ff0087	199 ff00af	200 ff00d7	201 ff00ff	202 ff5f00	203 ff05f5f	204 ff5f87	205 ff5f87	206 ff5fd7	207 ff5fff
208 ff8700	209 ff875f	210 ff8787	211 ff87af	212 ff87d7	213 ff87ff	214 ffaf00	215 ff0af5f	216 ffaf87	217 ffaf87	218 ffafd7	219 ffafff
220 ffd700	221 ffd75f	222 ffd787	223 ffd7af	224 ffd7d7	225 ffd7ff	226 ffff00	227 ff0ff5f	228 ffff87	229 ffff87	230 ffffd7	231 ffffff

I display this in index-order, which also puts the colors in rgb-logical order. Many display this as a cube without concern for index order. I personally think it would make more sense to display it as a cylinder, with the right half of the above chart flipped, before being rolled up horizontally (i.e., make the left and right edges meet after flipping the right half).

Open vs FreeBSD -- Night and Day

nospam@example.com (John) — Thu, 19 Mar 2015 13:36:00 +0000

I have switched to FreeBSD after spending a few months banging my head against OpenBSD. OpenBSD is a nice O.S., and I really didn't want to switch, but now that I'm trying FreeBSD, here are some first impressions of the differences.

Reasons to Choose FreeBSD

Would you like clear, well-written user documentation, instead of curt citations of man pages, and faq entries? You want FreeBSD.
Would you like to experiment with hosting MS-Windows (or Linux, or another BSD, etc.) as a guest O.S. in a virtual machine, right out of the box? You probably want FreeBSD.
You have an older machine with only 1/2 gig of ram, and you think you should be able to run firefox without hitting the swap file? Free is the O.S. for you.
You have an older computer that runs at just under 1 gighz, and you think it's reasonable to expect an O.S. to deliver decent performance from that? You need FreeBSD
You've invested a lot of time switching from MS-Office to OpenOffice and you don't want to have to now learn the latest other OTHER office suite? Definitely, you want FreeBSD.
You're an experimenter who wants to install BSD on your Raspberry Pi? Most seem to agree, FreeBSD is a better fit for you.

Reasons to Choose OpenBSD

You think PF (Packet Filter) is a really cool piece of software and you want to run it? OpenBSD is for you.

And Now, for Something Completely Different

Are you a masochist who is excited by the idea of being beaten to a pulp, and left naked in the middle of the ethical, legal, and financial mine-field that is the GPL?. . . You want linux.

John's Junk Drawer - Programming

The xterm 256-color table (set colors in xterm or PuTTY)

Open vs FreeBSD -- Night and Day