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Basic invocation:

  tattr [optional-params] [attrs: string...]

Emit to stdout an escape string activating text colors/styles, honoring $NO_COLOR & also reading ~/.config/cligen for $LC_THEME-based SGR aliases.

Regular/ANSI dim color keywords are in lower case while the bright bank is in UPPER CASE. This is the list of both:

  • dim black red green yellow blue purple cyan white
  • lite BLACK RED GREEN YELLOW BLUE PURPLE CYAN WHITE

Colors are foreground by default. Pre-pend the string "on_" for Background. So, e.g. YELLOW on_red will be bright yellow text on dark red background.

You can use this to e.g.

echo "$(tattr WHITE on_blue)some$(tattr WHITE on_blue)other$(tattr plain)"

{ If you do things like this often, you may want your shell PS1 prompt variable to contain an \\e[m ANSI SGR Escape color deactivation substring so that it's ok to forget the tattr off at the end. }

More colors when supported by the terminal

256-color terminals like xterm-256|st|kitty|alacritty also support:

  • {fbu}[0..23] for F)ORE/B)ACKground grey scale (1..2 decimal digits)
  • {fbu}RGB where each of R, G, B is in 0..5 (3 decimal digits)

as in:

echo "$(tattr f153 b4)hello in green-on-gray4"

True color terminals (xterm|st|kitty|..) additionally support:

  • {fbu}RRGGBB with RR, GG, BB are in hexadecimal (6 hex digits)

as in:

echo "$(tattr f28FFA0 b303030)hello in green-on-gray"

For both of the above, a "u" refers to the foreground color of underline or undercurl (or any underfoo, really).

Even more ways to specify color

An element of color scale NAME {viridis hue wLen gray pm3d} can be chosen via:

{fbu}sNAME<0.-1>[,..]

where only hue and wLen take [,sat,val] optionally. "wLen" is for "waveLength" - (yes, I know RGB light is a mixture; terms are just to contrast with "frequency order" or hot..cold / cold..hot). This can be useful in making 1-1 mappings between numerical ranges and colors.

More styles when supported by the terminal

Non-color styles are:

  • bold - most terminals support this, some mapping to HIGH
  • faint - few terminals support this
  • italic - many terminals support this
  • inverse - all terminals I know of support this
  • struck - few terminals support this
  • blink (slow) - most terminals support this..
  • BLINK (fast) - ..or the above, but often not 2 speeds
  • underline - sometimes mapped back/forth to italic
  • underdouble - kitty/alacritty added these extensions
  • underdot - ..The names after "under" refer to the
  • underdash - ..shape/style underneath the rendered
  • undercurl - ..text which can also have its own color.

These can be prefixed with '-' for the turn off esc sequence.

Rationale/Related Work

The main rationale of this utility is to "fit well" with other cligen tools and related configurations like lc, procs, hldiff, cligen help output, etc. While you can do things like:

echo $(tput setaf 214)256 $(tput setaf 202)colors

they will not honor .config/cligen/$LC_THEME switching or any color aliases stored in said themes. Meanwhile, if you have a 6 color hue range defined on-top of the 8-ANSI color scheme you can say tattr fhue0 or tattr fhue5. Or maybe you prefer the whole English word style for attribute naming which is usually less abbreviated than terminfo/termcap, culturally.

It is also more|less a 1-line proc and a locus for documenting my very compact syntax for SGR ANSI terminal attribute specification. As a simple side-effect it also lets you use all these terminal attributes easily from shell scripts.