Term::ANSIColor(3p) Perl Programmers Reference Guide Term::ANSIColor(3p) #
Term::ANSIColor(3p) Perl Programmers Reference Guide Term::ANSIColor(3p)
NNAAMMEE #
Term::ANSIColor - Color screen output using ANSI escape sequences
SSYYNNOOPPSSIISS #
use Term::ANSIColor;
print color('bold blue');
print "This text is bold blue.\n";
print color('reset');
print "This text is normal.\n";
print colored("Yellow on magenta.", 'yellow on_magenta'), "\n";
print "This text is normal.\n";
print colored(['yellow on_magenta'], 'Yellow on magenta.', "\n");
print colored(['red on_bright_yellow'], 'Red on bright yellow.', "\n");
print colored(['bright_red on_black'], 'Bright red on black.', "\n");
print "\n";
# Map escape sequences back to color names.
use Term::ANSIColor 1.04 qw(uncolor);
my @names = uncolor('01;31');
print join(q{ }, @names), "\n";
# Strip all color escape sequences.
use Term::ANSIColor 2.01 qw(colorstrip);
print colorstrip("\e[1mThis is bold\e[0m"), "\n";
# Determine whether a color is valid.
use Term::ANSIColor 2.02 qw(colorvalid);
my $valid = colorvalid('blue bold', 'on_magenta');
print "Color string is ", $valid ? "valid\n" : "invalid\n";
# Create new aliases for colors.
use Term::ANSIColor 4.00 qw(coloralias);
coloralias('alert', 'red');
print "Alert is ", coloralias('alert'), "\n";
print colored("This is in red.", 'alert'), "\n";
use Term::ANSIColor qw(:constants);
print BOLD, BLUE, "This text is in bold blue.\n", RESET;
use Term::ANSIColor qw(:constants);
{
local $Term::ANSIColor::AUTORESET = 1;
print BOLD BLUE "This text is in bold blue.\n";
print "This text is normal.\n";
}
use Term::ANSIColor 2.00 qw(:pushpop);
print PUSHCOLOR RED ON_GREEN "This text is red on green.\n";
print PUSHCOLOR BRIGHT_BLUE "This text is bright blue on green.\n";
print RESET BRIGHT_BLUE "This text is just bright blue.\n";
print POPCOLOR "Back to red on green.\n";
print LOCALCOLOR GREEN ON_BLUE "This text is green on blue.\n";
print "This text is red on green.\n";
{
local $Term::ANSIColor::AUTOLOCAL = 1;
print ON_BLUE "This text is red on blue.\n";
print "This text is red on green.\n";
}
print POPCOLOR "Back to whatever we started as.\n";
DDEESSCCRRIIPPTTIIOONN #
This module has two interfaces, one through ccoolloorr(()) and ccoolloorreedd(()) and the
other through constants. It also offers the utility functions uunnccoolloorr(()),
ccoolloorrssttrriipp(()), ccoolloorrvvaalliidd(()), and ccoolloorraalliiaass(()), which have to be explicitly
imported to be used (see "SYNOPSIS").
If you are using Term::ANSIColor in a console command, consider
supporting the CLICOLOR standard. See "Supporting CLICOLOR" for more
information.
See "COMPATIBILITY" for the versions of Term::ANSIColor that introduced
particular features and the versions of Perl that included them.
SSuuppppoorrtteedd CCoolloorrss Terminal emulators that support color divide into four types: ones that support only eight colors, ones that support sixteen, ones that support 256, and ones that support 24-bit color. This module provides the ANSI escape codes for all of them. These colors are referred to as ANSI colors 0 through 7 (normal), 8 through 15 (16-color), 16 through 255 (256-color), and true color (called direct-color by xxtteerrmm).
Unfortunately, interpretation of colors 0 through 7 often depends on
whether the emulator supports eight colors or sixteen colors. Emulators
that only support eight colors (such as the Linux console) will display
colors 0 through 7 with normal brightness and ignore colors 8 through 15,
treating them the same as white. Emulators that support 16 colors, such
as gnome-terminal, normally display colors 0 through 7 as dim or darker
versions and colors 8 through 15 as normal brightness. On such
emulators, the "normal" white (color 7) usually is shown as pale grey,
requiring bright white (15) to be used to get a real white color. Bright
black usually is a dark grey color, although some terminals display it as
pure black. Some sixteen-color terminal emulators also treat normal
yellow (color 3) as orange or brown, and bright yellow (color 11) as
yellow.
Following the normal convention of sixteen-color emulators, this module
provides a pair of attributes for each color. For every normal color (0
through 7), the corresponding bright color (8 through 15) is obtained by
prepending the string "bright_" to the normal color name. For example,
"red" is color 1 and "bright_red" is color 9. The same applies for
background colors: "on_red" is the normal color and "on_bright_red" is
the bright color. Capitalize these strings for the constant interface.
There is unfortunately no way to know whether the current emulator
supports more than eight colors, which makes the choice of colors
difficult. The most conservative choice is to use only the regular
colors, which are at least displayed on all emulators. However, they
will appear dark in sixteen-color terminal emulators, including most
common emulators in UNIX X environments. If you know the display is one
of those emulators, you may wish to use the bright variants instead.
Even better, offer the user a way to configure the colors for a given
application to fit their terminal emulator.
For 256-color emulators, this module additionally provides "ansi0"
through "ansi15", which are the same as colors 0 through 15 in sixteen-
color emulators but use the 256-color escape syntax, "grey0" through
"grey23" ranging from nearly black to nearly white, and a set of RGB
colors. The RGB colors are of the form "rgb_R_G_B" where _R, _G, and _B are
numbers from 0 to 5 giving the intensity of red, green, and blue. The
grey and RGB colors are also available as "ansi16" through "ansi255" if
you want simple names for all 256 colors. "on_" variants of all of these
colors are also provided. These colors may be ignored completely on
non-256-color terminals or may be misinterpreted and produce random
behavior. Additional attributes such as blink, italic, or bold may not
work with the 256-color palette.
For true color emulators, this module supports attributes of the form
"r_N_N_Ng_N_N_Nb_N_N_N" and "on_r_N_N_Ng_N_N_Nb_N_N_N" for all values of _N_N_N between 0 and
255. These represent foreground and background colors, respectively,
with the RGB values given by the _N_N_N numbers. These colors may be
ignored completely on non-true-color terminals or may be misinterpreted
and produce random behavior.
FFuunnccttiioonn IInntteerrffaaccee The function interface uses attribute strings to describe the colors and text attributes to assign to text. The recognized non-color attributes are clear, reset, bold, dark, faint, italic, underline, underscore, blink, reverse, and concealed. Clear and reset (reset to default attributes), dark and faint (dim and saturated), and underline and underscore are equivalent, so use whichever is the most intuitive to you.
Note that not all attributes are supported by all terminal types, and
some terminals may not support any of these sequences. Dark and faint,
italic, blink, and concealed in particular are frequently not
implemented.
The recognized normal foreground color attributes (colors 0 to 7) are:
black red green yellow blue magenta cyan white
The corresponding bright foreground color attributes (colors 8 to 15)
are:
bright_black bright_red bright_green bright_yellow
bright_blue bright_magenta bright_cyan bright_white
The recognized normal background color attributes (colors 0 to 7) are:
on_black on_red on_green on yellow
on_blue on_magenta on_cyan on_white
The recognized bright background color attributes (colors 8 to 15) are:
on_bright_black on_bright_red on_bright_green on_bright_yellow
on_bright_blue on_bright_magenta on_bright_cyan on_bright_white
For 256-color terminals, the recognized foreground colors are:
ansi0 .. ansi255
grey0 .. grey23
plus "rgb_R_G_B" for _R, _G, and _B values from 0 to 5, such as "rgb000" or
"rgb515". Similarly, the recognized background colors are:
on_ansi0 .. on_ansi255
on_grey0 .. on_grey23
plus "on_rgb_R_G_B" for _R, _G, and _B values from 0 to 5.
For true color terminals, the recognized foreground colors are
"r_R_R_Rg_G_G_Gb_B_B_B" for _R_R_R, _G_G_G, and _B_B_B values between 0 and 255.
Similarly, the recognized background colors are "on_r_R_R_Rg_G_G_Gb_B_B_B" for
_R_R_R, _G_G_G, and _B_B_B values between 0 and 255.
For any of the above listed attributes, case is not significant.
Attributes, once set, last until they are unset (by printing the
attribute "clear" or "reset"). Be careful to do this, or otherwise your
attribute will last after your script is done running, and people get
very annoyed at having their prompt and typing changed to weird colors.
color(ATTR[, ATTR ...])
ccoolloorr(()) takes any number of strings as arguments and considers them
to be space-separated lists of attributes. It then forms and returns
the escape sequence to set those attributes. It doesn't print it
out, just returns it, so you'll have to print it yourself if you want
to. This is so that you can save it as a string, pass it to
something else, send it to a file handle, or do anything else with it
that you might care to. ccoolloorr(()) throws an exception if given an
invalid attribute.
colored(STRING, ATTR[, ATTR ...])
colored(ATTR-REF, STRING[, STRING...])
As an aid in resetting colors, ccoolloorreedd(()) takes a scalar as the first
argument and any number of attribute strings as the second argument
and returns the scalar wrapped in escape codes so that the attributes
will be set as requested before the string and reset to normal after
the string. Alternately, you can pass a reference to an array as the
first argument, and then the contents of that array will be taken as
attributes and color codes and the remainder of the arguments as text
to colorize.
Normally, ccoolloorreedd(()) just puts attribute codes at the beginning and
end of the string, but if you set $Term::ANSIColor::EACHLINE to some
string, that string will be considered the line delimiter and the
attribute will be set at the beginning of each line of the passed
string and reset at the end of each line. This is often desirable if
the output contains newlines and you're using background colors,
since a background color that persists across a newline is often
interpreted by the terminal as providing the default background color
for the next line. Programs like pagers can also be confused by
attributes that span lines. Normally you'll want to set
$Term::ANSIColor::EACHLINE to "\n" to use this feature.
Particularly consider setting $Term::ANSIColor::EACHLINE if you are
interleaving output to standard output and standard error and you
aren't flushing standard output (via aauuttoofflluusshh(()) or setting $|). If
you don't, the code to reset the color may unexpectedly sit in the
standard output buffer rather than going to the display, causing
standard error output to appear in the wrong color.
uncolor(ESCAPE)
uunnccoolloorr(()) performs the opposite translation as ccoolloorr(()), turning
escape sequences into a list of strings corresponding to the
attributes being set by those sequences. uunnccoolloorr(()) will never return
"ansi16" through "ansi255", instead preferring the "grey" and "rgb"
names (and likewise for "on_ansi16" through "on_ansi255").
colorstrip(STRING[, STRING ...])
ccoolloorrssttrriipp(()) removes all color escape sequences from the provided
strings, returning the modified strings separately in array context
or joined together in scalar context. Its arguments are not
modified.
colorvalid(ATTR[, ATTR ...])
ccoolloorrvvaalliidd(()) takes attribute strings the same as ccoolloorr(()) and returns
true if all attributes are known and false otherwise.
coloralias(ALIAS[, ATTR ...])
If ATTR is specified, it is interpreted as a list of space-separated
strings naming attributes or existing aliases. In this case,
ccoolloorraalliiaass(()) sets up an alias of ALIAS for the set of attributes
given by ATTR. From that point forward, ALIAS can be passed into
ccoolloorr(()), ccoolloorreedd(()), and ccoolloorrvvaalliidd(()) and will have the same meaning
as the sequence of attributes given in ATTR. One possible use of
this facility is to give more meaningful names to the 256-color RGB
colors. Only ASCII alphanumerics, ".", "_", and "-" are allowed in
alias names.
If ATTR includes aliases, those aliases will be expanded at
definition time and their values will be used to define the new
alias. This means that if you define an alias A in terms of another
alias B, and then later redefine alias B, the value of alias A will
not change.
If ATTR is not specified, ccoolloorraalliiaass(()) returns the standard attribute
or attributes to which ALIAS is aliased, if any, or undef if ALIAS
does not exist. If it is aliased to multiple attributes, the return
value will be a single string and the attributes will be separated by
spaces.
This is the same facility used by the ANSI_COLORS_ALIASES environment
variable (see "ENVIRONMENT" below) but can be used at runtime, not
just when the module is loaded.
Later invocations of ccoolloorraalliiaass(()) with the same ALIAS will override
earlier aliases. There is no way to remove an alias.
Aliases have no effect on the return value of uunnccoolloorr(()).
WWAARRNNIINNGG: Aliases are global and affect all callers in the same
process. There is no way to set an alias limited to a particular
block of code or a particular object.
CCoonnssttaanntt IInntteerrffaaccee Alternately, if you import “:constants”, you can use the following constants directly:
CLEAR RESET BOLD DARK #
FAINT ITALIC UNDERLINE UNDERSCORE #
BLINK REVERSE CONCEALED #
BLACK RED GREEN YELLOW #
BLUE MAGENTA CYAN WHITE #
BRIGHT_BLACK BRIGHT_RED BRIGHT_GREEN BRIGHT_YELLOW #
BRIGHT_BLUE BRIGHT_MAGENTA BRIGHT_CYAN BRIGHT_WHITE #
ON_BLACK ON_RED ON_GREEN ON_YELLOW #
ON_BLUE ON_MAGENTA ON_CYAN ON_WHITE #
ON_BRIGHT_BLACK ON_BRIGHT_RED ON_BRIGHT_GREEN ON_BRIGHT_YELLOW #
ON_BRIGHT_BLUE ON_BRIGHT_MAGENTA ON_BRIGHT_CYAN ON_BRIGHT_WHITE #
These are the same as color('attribute') and can be used if you prefer
typing:
print BOLD BLUE ON_WHITE "Text", RESET, "\n";
to
print colored ("Text", 'bold blue on_white'), "\n";
(Note that the newline is kept separate to avoid confusing the terminal
as described above since a background color is being used.)
If you import ":constants256", you can use the following constants
directly:
ANSI0 .. ANSI255 #
GREY0 .. GREY23 #
RGBXYZ (for X, Y, and Z values from 0 to 5, like RGB000 or RGB515)
ON_ANSI0 .. ON_ANSI255 #
ON_GREY0 .. ON_GREY23 #
ON_RGBXYZ (for X, Y, and Z values from 0 to 5)
Note that ":constants256" does not include the other constants, so if you
want to mix both, you need to include ":constants" as well. You may want
to explicitly import at least "RESET", as in:
use Term::ANSIColor 4.00 qw(RESET :constants256);
True color and aliases are not supported by the constant interface.
When using the constants, if you don't want to have to remember to add
the ", RESET" at the end of each print line, you can set
$Term::ANSIColor::AUTORESET to a true value. Then, the display mode will
automatically be reset if there is no comma after the constant. In other
words, with that variable set:
print BOLD BLUE "Text\n";
will reset the display mode afterward, whereas:
print BOLD, BLUE, "Text\n";
will not. If you are using background colors, you will probably want to
either use ssaayy(()) (in newer versions of Perl) or print the newline with a
separate print statement to avoid confusing the terminal.
If $Term::ANSIColor::AUTOLOCAL is set (see below), it takes precedence
over $Term::ANSIColor::AUTORESET, and the latter is ignored.
The subroutine interface has the advantage over the constants interface
in that only two subroutines are exported into your namespace, versus
thirty-eight in the constants interface, and aliases and true color
attributes are supported. On the flip side, the constants interface has
the advantage of better compile time error checking, since misspelled
names of colors or attributes in calls to ccoolloorr(()) and ccoolloorreedd(()) won't be
caught until runtime whereas misspelled names of constants will be caught
at compile time. So, pollute your namespace with almost two dozen
subroutines that you may not even use that often, or risk a silly bug by
mistyping an attribute. Your choice, TMTOWTDI after all.
TThhee CCoolloorr SSttaacckk You can import “:pushpop” and maintain a stack of colors using PUSHCOLOR, POPCOLOR, and LOCALCOLOR. PUSHCOLOR takes the attribute string that starts its argument and pushes it onto a stack of attributes. POPCOLOR removes the top of the stack and restores the previous attributes set by the argument of a prior PUSHCOLOR. LOCALCOLOR surrounds its argument in a PUSHCOLOR and POPCOLOR so that the color resets afterward.
If $Term::ANSIColor::AUTOLOCAL is set, each sequence of color constants
will be implicitly preceded by LOCALCOLOR. In other words, the
following:
{
local $Term::ANSIColor::AUTOLOCAL = 1;
print BLUE "Text\n";
}
is equivalent to:
print LOCALCOLOR BLUE "Text\n";
If $Term::ANSIColor::AUTOLOCAL is set, it takes precedence over
$Term::ANSIColor::AUTORESET, and the latter is ignored.
When using PUSHCOLOR, POPCOLOR, and LOCALCOLOR, it's particularly
important to not put commas between the constants.
print PUSHCOLOR BLUE "Text\n";
will correctly push BLUE onto the top of the stack.
print PUSHCOLOR, BLUE, "Text\n"; # wrong!
will not, and a subsequent pop won't restore the correct attributes.
PUSHCOLOR pushes the attributes set by its argument, which is normally a
string of color constants. It can't ask the terminal what the current
attributes are.
SSuuppppoorrttiinngg CCLLIICCOOLLOORR https://bixense.com/clicolors/ proposes a standard for enabling and disabling color output from console commands using two environment variables, CLICOLOR and CLICOLOR_FORCE. Term::ANSIColor cannot automatically support this standard, since the correct action depends on where the output is going and Term::ANSIColor may be used in a context where colors should always be generated even if CLICOLOR is set in the environment. But you can use the supported environment variable ANSI_COLORS_DISABLED to implement CLICOLOR in your own programs with code like this:
if (exists($ENV{CLICOLOR}) && $ENV{CLICOLOR} == 0) {
if (!$ENV{CLICOLOR_FORCE}) {
$ENV{ANSI_COLORS_DISABLED} = 1; #
}
}
If you are using the constant interface, be sure to include this code
before you use any color constants (such as at the very top of your
script), since this environment variable is only honored the first time a
color constant is seen.
Be aware that this will export ANSI_COLORS_DISABLED to any child
processes of your program as well.
DDIIAAGGNNOOSSTTIICCSS #
Bad color mapping %s
(W) The specified color mapping from ANSI_COLORS_ALIASES is not valid
and could not be parsed. It was ignored.
Bad escape sequence %s
(F) You passed an invalid ANSI escape sequence to uunnccoolloorr(()).
Bareword "%s" not allowed while "strict subs" in use
(F) You probably mistyped a constant color name such as:
$Foobar = FOOBAR . "This line should be blue\n";
or:
@Foobar = FOOBAR, "This line should be blue\n";
This will only show up under use strict (another good reason to run
under use strict).
Cannot alias standard color %s
(F) The alias name passed to ccoolloorraalliiaass(()) matches a standard color
name. Standard color names cannot be aliased.
Cannot alias standard color %s in %s
(W) The same, but in ANSI_COLORS_ALIASES. The color mapping was
ignored.
Invalid alias name %s
(F) You passed an invalid alias name to ccoolloorraalliiaass(()). Alias names
must consist only of alphanumerics, ".", "-", and "_".
Invalid alias name %s in %s
(W) You specified an invalid alias name on the left hand of the equal
sign in a color mapping in ANSI_COLORS_ALIASES. The color mapping
was ignored.
Invalid attribute name %s
(F) You passed an invalid attribute name to ccoolloorr(()), ccoolloorreedd(()), or
ccoolloorraalliiaass(()).
Invalid attribute name %s in %s
(W) You specified an invalid attribute name on the right hand of the
equal sign in a color mapping in ANSI_COLORS_ALIASES. The color
mapping was ignored.
Name "%s" used only once: possible typo
(W) You probably mistyped a constant color name such as:
print FOOBAR "This text is color FOOBAR\n";
It's probably better to always use commas after constant names in
order to force the next error.
No comma allowed after filehandle
(F) You probably mistyped a constant color name such as:
print FOOBAR, "This text is color FOOBAR\n";
Generating this fatal compile error is one of the main advantages of
using the constants interface, since you'll immediately know if you
mistype a color name.
No name for escape sequence %s
(F) The ANSI escape sequence passed to uunnccoolloorr(()) contains escapes
which aren't recognized and can't be translated to names.
EENNVVIIRROONNMMEENNTT #
ANSI_COLORS_ALIASES #
This environment variable allows the user to specify custom color
aliases that will be understood by ccoolloorr(()), ccoolloorreedd(()), and
ccoolloorrvvaalliidd(()). None of the other functions will be affected, and no
new color constants will be created. The custom colors are aliases
for existing color names; no new escape sequences can be introduced.
Only alphanumerics, ".", "_", and "-" are allowed in alias names.
The format is:
ANSI_COLORS_ALIASES='newcolor1=oldcolor1,newcolor2=oldcolor2'
Whitespace is ignored. The alias value can be a single attribute or
a space-separated list of attributes.
For example the Solarized <https://ethanschoonover.com/solarized>
colors can be mapped with:
ANSI_COLORS_ALIASES='\ #
base00=bright_yellow, on_base00=on_bright_yellow,\
base01=bright_green, on_base01=on_bright_green, \
base02=black, on_base02=on_black, \
base03=bright_black, on_base03=on_bright_black, \
base0=bright_blue, on_base0=on_bright_blue, \
base1=bright_cyan, on_base1=on_bright_cyan, \
base2=white, on_base2=on_white, \
base3=bright_white, on_base3=on_bright_white, \
orange=bright_red, on_orange=on_bright_red, \
violet=bright_magenta,on_violet=on_bright_magenta'
This environment variable is read and applied when the
Term::ANSIColor module is loaded and is then subsequently ignored.
Changes to ANSI_COLORS_ALIASES after the module is loaded will have
no effect. See ccoolloorraalliiaass(()) for an equivalent facility that can be
used at runtime.
ANSI_COLORS_DISABLED #
If this environment variable is set to a true value, all of the
functions defined by this module (ccoolloorr(()), ccoolloorreedd(()), and all of the
constants) will not output any escape sequences and instead will just
return the empty string or pass through the original text as
appropriate. This is intended to support easy use of scripts using
this module on platforms that don't support ANSI escape sequences.
NO_COLOR #
If this environment variable is set to any value, it suppresses
generation of escape sequences the same as if ANSI_COLORS_DISABLED is
set to a true value. This implements the <https://no-color.org/>
informal standard. Programs that want to enable color despite
NO_COLOR being set will need to unset that environment variable
before any constant or function provided by this module is used.
CCOOMMPPAATTIIBBIILLIITTYY #
Term::ANSIColor was first included with Perl in Perl 5.6.0.
The uunnccoolloorr(()) function and support for ANSI_COLORS_DISABLED were added in
Term::ANSIColor 1.04, included in Perl 5.8.0.
Support for dark was added in Term::ANSIColor 1.08, included in Perl
5.8.4.
The color stack, including the ":pushpop" import tag, PUSHCOLOR,
POPCOLOR, LOCALCOLOR, and the $Term::ANSIColor::AUTOLOCAL variable, was
added in Term::ANSIColor 2.00, included in Perl 5.10.1.
ccoolloorrssttrriipp(()) was added in Term::ANSIColor 2.01 and ccoolloorrvvaalliidd(()) was added
in Term::ANSIColor 2.02, both included in Perl 5.11.0.
Support for colors 8 through 15 (the "bright_" variants) was added in
Term::ANSIColor 3.00, included in Perl 5.13.3.
Support for italic was added in Term::ANSIColor 3.02, included in Perl
5.17.1.
Support for colors 16 through 256 (the "ansi", "rgb", and "grey" colors),
the ":constants256" import tag, the ccoolloorraalliiaass(()) function, and support
for the ANSI_COLORS_ALIASES environment variable were added in
Term::ANSIColor 4.00, included in Perl 5.17.8.
$Term::ANSIColor::AUTOLOCAL was changed to take precedence over
$Term::ANSIColor::AUTORESET, rather than the other way around, in
Term::ANSIColor 4.00, included in Perl 5.17.8.
"ansi16" through "ansi255", as aliases for the "rgb" and "grey" colors,
and the corresponding "on_ansi" names and "ANSI" and "ON_ANSI" constants
were added in Term::ANSIColor 4.06, included in Perl 5.25.7.
Support for true color (the "rNNNgNNNbNNN" and "on_rNNNgNNNbNNN"
attributes), defining aliases in terms of other aliases, and aliases
mapping to multiple attributes instead of only a single attribute was
added in Term::ANSIColor 5.00.
Support for NO_COLOR was added in Term::ANSIColor 5.01.
RREESSTTRRIICCTTIIOONNSS #
Both ccoolloorreedd(()) and many uses of the color constants will add the reset
escape sequence after a newline. If a program mixes colored output to
standard output with output to standard error, this can result in the
standard error text having the wrong color because the reset escape
sequence hasn't yet been flushed to the display (since standard output to
a terminal is line-buffered by default). To avoid this, either set
aauuttoofflluusshh(()) on STDOUT or set $Term::ANSIColor::EACHLINE to "\n".
It would be nice if one could leave off the commas around the constants
entirely and just say:
print BOLD BLUE ON_WHITE "Text\n" RESET;
but the syntax of Perl doesn't allow this. You need a comma after the
string. (Of course, you may consider it a bug that commas between all
the constants aren't required, in which case you may feel free to insert
commas unless you're using $Term::ANSIColor::AUTORESET or
PUSHCOLOR/POPCOLOR.) #
For easier debugging, you may prefer to always use the commas when not
setting $Term::ANSIColor::AUTORESET or PUSHCOLOR/POPCOLOR so that you'll
get a fatal compile error rather than a warning.
It's not possible to use this module to embed formatting and color
attributes using Perl formats. They replace the escape character with a
space (as documented in ppeerrllffoorrmm(1)), resulting in garbled output from
the unrecognized attribute. Even if there were a way around that
problem, the format doesn't know that the non-printing escape sequence is
zero-length and would incorrectly format the output. For formatted
output using color or other attributes, either use sspprriinnttff(()) instead or
use ffoorrmmlliinnee(()) and then add the color or other attributes after
formatting and before output.
NNOOTTEESS #
The codes generated by this module are standard terminal control codes,
complying with ECMA-048 and ISO 6429 (generally referred to as "ANSI
color" for the color codes). The non-color control codes (bold, dark,
italic, underline, and reverse) are part of the earlier ANSI X3.64
standard for control sequences for video terminals and peripherals.
Note that not all displays are ISO 6429-compliant, or even
X3.64-compliant (or are even attempting to be so). This module will not
work as expected on displays that do not honor these escape sequences,
such as cmd.exe, 4nt.exe, and command.com under either Windows NT or
Windows 2000. They may just be ignored, or they may display as an ESC
character followed by some apparent garbage.
Jean Delvare provided the following table of different common terminal
emulators and their support for the various attributes and others have
helped me flesh it out:
clear bold faint under blink reverse conceal
------------------------------------------------------------------------
xterm yes yes no yes yes yes yes
linux yes yes yes bold yes yes no
rxvt yes yes no yes bold/black yes no
dtterm yes yes yes yes reverse yes yes
teraterm yes reverse no yes rev/red yes no
aixterm kinda normal no yes no yes yes
PuTTY yes color no yes no yes no
Windows yes no no no no yes no
Cygwin SSH yes yes no color color color yes
Terminal.app yes yes no yes yes yes yes
Windows is Windows telnet, Cygwin SSH is the OpenSSH implementation under
Cygwin on Windows NT, and Mac Terminal is the Terminal application in Mac
OS X. Where the entry is other than yes or no, that emulator displays
the given attribute as something else instead. Note that on an aixterm,
clear doesn't reset colors; you have to explicitly set the colors back to
what you want. More entries in this table are welcome.
Support for code 3 (italic) is rare and therefore not mentioned in that
table. It is not believed to be fully supported by any of the terminals
listed, although it's displayed as green in the Linux console, but it is
reportedly supported by urxvt.
Note that codes 6 (rapid blink) and 9 (strike-through) are specified in
ANSI X3.64 and ECMA-048 but are not commonly supported by most displays
and emulators and therefore aren't supported by this module. ECMA-048
also specifies a large number of other attributes, including a sequence
of attributes for font changes, Fraktur characters, double-underlining,
framing, circling, and overlining. As none of these attributes are
widely supported or useful, they also aren't currently supported by this
module.
Most modern X terminal emulators support 256 colors. Known to not
support those colors are aterm, rxvt, Terminal.app, and TTY/VC.
For information on true color support in various terminal emulators, see
True Colour support <https://gist.github.com/XVilka/8346728>.
AAUUTTHHOORRSS #
Original idea (using constants) by Zenin, reimplemented using subs by
Russ Allbery <rra@cpan.org>, and then combined with the original idea by
Russ with input from Zenin. 256-color support is based on work by Kurt
Starsinic. Russ Allbery now maintains this module.
PUSHCOLOR, POPCOLOR, and LOCALCOLOR were contributed by openmethods.com
voice solutions.
CCOOPPYYRRIIGGHHTT AANNDD LLIICCEENNSSEE #
Copyright 1996-1998, 2000-2002, 2005-2006, 2008-2018, 2020 Russ Allbery
<rra@cpan.org>
Copyright 1996 Zenin
Copyright 2012 Kurt Starsinic <kstarsinic@gmail.com>
This program is free software; you may redistribute it and/or modify it
under the same terms as Perl itself.
SSEEEE AALLSSOO #
The CPAN module Term::ExtendedColor provides a different and more
comprehensive interface for 256-color emulators that may be more
convenient. The CPAN module Win32::Console::ANSI provides ANSI color
(and other escape sequence) support in the Win32 Console environment.
The CPAN module Term::Chrome provides a different interface using objects
and operator overloading.
ECMA-048 is available on-line (at least at the time of this writing) at
<https://www.ecma-international.org/publications/standards/Ecma-048.htm>.
ISO 6429 is available from ISO for a charge; the author of this module
does not own a copy of it. Since the source material for ISO 6429 was
ECMA-048 and the latter is available for free, there seems little reason
to obtain the ISO standard.
The 256-color control sequences are documented at
<https://invisible-island.net/xterm/ctlseqs/ctlseqs.html> (search for
256-color).
Information about true color support in various terminal emulators and
test programs you can run to check the true color support in your
terminal emulator are available at
<https://gist.github.com/XVilka/8346728>.
CLICOLORS <https://bixense.com/clicolors/> and NO_COLOR <https://no-
color.org/> are useful standards to be aware of, and ideally follow, for
any application using color. Term::ANSIColor complies with the latter.
The current version of this module is always available from its web site
at <https://www.eyrie.org/~eagle/software/ansicolor/>. It is also part
of the Perl core distribution as of 5.6.0.
perl v5.36.3 2021-03-02 Term::ANSIColor(3p)