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Term::ANSIColor

Term::ANSIColor(3)     Perl Programmers Reference Guide     Term::ANSIColor(3)



NAME
       Term::ANSIColor - Color screen output using ANSI escape sequences

SYNOPSIS
           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.\n", 'yellow on_magenta');
           print "This text is normal.\n";
           print colored ['yellow on_magenta'], "Yellow on magenta.\n";

           use Term::ANSIColor qw(uncolor);
           print uncolor '01;31', "\n";

           use Term::ANSIColor qw(:constants);
           print BOLD, BLUE, "This text is in bold blue.\n", RESET;

           use Term::ANSIColor qw(:constants);
           $Term::ANSIColor::AUTORESET = 1;
           print BOLD BLUE "This text is in bold blue.\n";
           print "This text is normal.\n";

DESCRIPTION
       This module has two interfaces, one through color() and colored() and
       the other through constants.  It also offers the utility function
       uncolor(), which has to be explicitly imported to be used (see SYNOP-
       SIS).

       color() 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).

       uncolor() performs the opposite translation, turning escape sequences
       into a list of strings.

       The recognized attributes (all of which should be fairly intuitive) are
       clear, reset, dark, bold, underline, underscore, blink, reverse, con-
       cealed, black, red, green, yellow, blue, magenta, on_black, on_red,
       on_green, on_yellow, on_blue, on_magenta, on_cyan, and on_white.  Case
       is not significant.  Underline and underscore are equivalent, as are
       clear and reset, so use whichever is the most intuitive to you.  The
       color alone sets the foreground color, and on_color sets the background
       color.

       Note that not all attributes are supported by all terminal types, and
       some terminals may not support any of these sequences.  Dark, blink,
       and concealed in particular are frequently not implemented.

       Attributes, once set, last until they are unset (by sending the
       attribute "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.

       As an aid to help with this, colored() 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, colored() 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 is being sent to a program like a pager that can be confused
       by attributes that span lines.  Normally you'll want to set
       $Term::ANSIColor::EACHLINE to "\n" to use this feature.

       Alternately, if you import ":constants", you can use the constants
       CLEAR, RESET, BOLD, DARK, UNDERLINE, UNDERSCORE, BLINK, REVERSE, CON-
       CEALED, BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE,
       ON_BLACK, ON_RED, ON_GREEN, ON_YELLOW, ON_BLUE, ON_MAGENTA, ON_CYAN,
       and ON_WHITE directly.  These are the same as color('attribute') and
       can be used if you prefer typing:

           print BOLD BLUE ON_WHITE "Text\n", RESET;

       to

           print colored ("Text\n", 'bold blue on_white');

       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::ANSI-
       Color::AUTORESET to a true value.  Then, the display mode will automat-
       ically 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 afterwards, whereas:

           print BOLD, BLUE, "Text\n";

       will not.

       The subroutine interface has the advantage over the constants interface
       in that only two subroutines are exported into your namespace, versus
       twenty-two in the constants interface.  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 color() and
       colored() won't be caught until runtime whereas misspelled names of
       constants will be caught at compile time.  So, polute 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.

DIAGNOSTICS
       Bad escape sequence %s
           (F) You passed an invalid ANSI escape sequence to uncolor().

       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).

       Invalid attribute name %s
           (F) You passed an invalid attribute name to either color() or col-
           ored().

       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 uncolor() contains escapes
           which aren't recognized and can't be translated to names.

ENVIRONMENT
       ANSI_COLORS_DISABLED
           If this environment variable is set, all of the functions defined
           by this module (color(), colored(), and all of the constants not
           previously used in the program) 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 sup-
           port easy use of scripts using this module on platforms that don't
           support ANSI escape sequences.

           For it to have its proper effect, this environment variable must be
           set before any color constants are used in the program.

RESTRICTIONS
       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.)

       For easier debuging, you may prefer to always use the commas when not
       setting $Term::ANSIColor::AUTORESET so that you'll get a fatal compile
       error rather than a warning.

NOTES
       The codes generated by this module are standard terminal control codes,
       complying with ECMA-48 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-com-
       pliant (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 charac-
       ter 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     dark    under    blink   reverse  conceal
        ------------------------------------------------------------------------
        xterm         yes      yes      no      yes     bold      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

       Windows is Windows telnet, and Cygwin SSH is the OpenSSH implementation
       under Cygwin on Windows NT.  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.

       Note that codes 3 (italic), 6 (rapid blink), and 9 (strikethrough) 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 mod-
       ule at the present time.  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 overlin-
       ing.  As none of these attributes are widely supported or useful, they
       also aren't currently supported by this module.

SEE ALSO
       ECMA-048 is available on-line (at least at the time of this writing) at
       <http://www.ecma-international.org/publications/stan-
       dards/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 rea-
       son to obtain the ISO standard.

       The current version of this module is always available from its web
       site at <http://www.eyrie.org/~eagle/software/ansicolor/>.  It is also
       part of the Perl core distribution as of 5.6.0.

AUTHORS
       Original idea (using constants) by Zenin, reimplemented using subs by
       Russ Allbery <rra@stanford.edu>, and then combined with the original
       idea by Russ with input from Zenin.  Russ Allbery now maintains this
       module.

COPYRIGHT AND LICENSE
       Copyright 1996, 1997, 1998, 2000, 2001, 2002 Russ Allbery <rra@stan-
       ford.edu> and Zenin <zenin@bawdycaste.org>.  This program is free soft-
       ware; you may redistribute it and/or modify it under the same terms as
       Perl itself.



perl v5.8.6                       2001-09-21                Term::ANSIColor(3)