Bug 250686

This is not a bug, the standard syntax of man pages is simple and the color tags
are not usually used. So there is no need to display man-pages using colors.

I know this is more a question than a bug: "How
to get color in man" ;-). But, since I've not been able to
get it, I think that this maybe a improvement or feature
request, to make it possible.

By default, in Fedora, man pages are shown with bold and 
underline. For example, if you type the command:

    man man

then you will see:

    NAME
           man  -  format  and  display the on-line manual
           pages
    
    SYNOPSIS
           man [-acdfFhkKtwW]  [--path]  [-m  system]  [-p
           string]  [-C  config_file]  [-M  pathlist]  [-P
           pager] [-B browser]  [-H  htmlpager]  [-S  sec-
           tion_list] [section] name ...
    
    (...)

In gnome-terminal (Fedora), the strings "NAME", "SYNOPSIS" 
and "man [-acdfFhkKtwW]" are shown in bold. The strings 
"system", "string" and "config_file"  are shown underlined.

In Cygwin (Windows), if you open the same manual page ("man
man"), the strings "NAME", "SYNOPSIS" and "man 
[-acdfFhkKtwW]" are not shown in bold, they are shown in 
one color (which I don't remember, maybe green). And the 
strings "system", "string" and "config_file" are not shown
underlined, they are shown in other color (maybe yellow).

So my question is how to get colors in Fedora too. This is,
how to replace "bold" by "color1", and "underlined" by
"color2".


From what I've investigated, running "man page" is
aproximately equivalent to this command:

    cat $path_to_page.gz | gunzip | $NROFF | $PAGER

where $NROFF and $PAGER are defined in /etc/man.config.

By default, those variables have these values:

    NROFF           /usr/bin/nroff -c -mandoc 2>/dev/null
    PAGER           /usr/bin/less -is


The "-c" in NROFF variable means:

    The -h and -c options are equivalent to grotty's
    options 

and in grotty we see:

    Use   the  -c  switch  to  revert  to  the  old
    behaviour, printing a bold character c with the
    sequence  'c BACKSPACE c' and an italic charac-
    ter c by the sequence '_ BACKSPACE c'.  At  the
    same  time, color output is disabled.

Then, if I delete the "-c" ("nroff -mandoc 2>/dev/null"),
colors should be enabled. Right?


For the PAGER variable, we can use colors in "less" command
if we add the "-R" option ("less -isR"). I've tested it with
the command "ls --color | less -R", and it works.


So, by using the following values in /etc/man.config:

    NROFF           /usr/bin/nroff -mandoc 2>/dev/null
    PAGER           /usr/bin/less -isR

bold style would be replaced by color1, and underlined 
style would be replaced by color2 , in all manual pages.
Like in cygwin.


Is that right? Perhaps nroff doesn't convert bold and
underline into color1 and color3, even if colors are
enabled? Maybe the conversion is a "gnome-terminal" 
question (~/.Xdefaults) instead of a "man" question 
(/etc/man.config)?

I can post the question at the gnome-terminal component, if
needed. Just tell me.


Thank you

Groff uses colors but they are different then you mean - it is possible in
"groff language" to write text with different colors and different colored
background. So nroff option -c switch of/on these colors (I don't find any
transformation from bold/underline/any other style to colors). less with -R
option accept these kind of colors. But in manual pages there are not used these
tags - so the text is black and white only.
but there are another programs which transformed bold and underlined text to
colored text (e.g. most) - so if you have installed most package you can use
most as a pager 
PAGER           /usr/bin/most
then there is no difference between the 
NROFF           /usr/bin/nroff -c -mandoc 2>/dev/null
and
NROFF           /usr/bin/nroff -mandoc 2>/dev/null
most command displays man-pages in colors. But most don't accept some special
characters (eg. quote), so less is the best "pager" and it is upstream choice too. 

I've tested "most". It has the problem you've said (the "'"
simbol is not well shown), and additionally I can't find 
how to keep the default background color for bold and 
underline styles when converted to colors.


I have three ideas to solve the problem of man+less:

1) Use some unix-style utilities to convert bold and
   underline into colors, and insert them into the piped
   chain of commands:

       cat $path_to_page.gz | gunzip | $NROFF \
       | bold2color -green | underl2color -yellow | $PAGER

   But I don't know if "bold2color" and "underl2color" do
   exist.

2) Customize the "groff_man" macro, which is used by the
   "-mandoc" option of nroff to convert original "groff
   language" of man pages into ascii output. So, it assign
   bold and underline style to some components of the
   original pages.

   The documentaton of this macro (see "man groff_man")
   explains that we can customize it:

       For further customization, put additional macros and
       requests into the file man.local which will be loaded
       immediately after the man package.

   But I don't know hot to customize it (I would need to
   "study" groff, which is nearly-infinite ;-).

3) Extend the "-D" option of less to unix (currently it's
   only supported in msdos). In this way, we could assign
   colors to bold and underline styles.

   But this would require some development.


In the meantime, I've found the "pman" command (surprisingly
it was installed by default in my Fedora, as part of the
pinfo package). It has a "navigable" interface, with links
to other pages, and can be customized in /etc/pinforc. In
that config file, bold and underline styles can be
converted into colors by using these variables:
    
    COL_MANUALBOLD
    COL_MANUALITALIC

and background can be kept with the "COLOR_DEFAULT" value.

Anyway, "pman" sets the color of some characters (Á É Í Ó
Ú) to default color, and works differently from "less". I'd
prefer man+less if some idea could be used to get colors.


Thank you