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[PATCH] help: colorize man pages

From
Felipe Contreras <felipe.contreras@gmail.com>
Date
May 18, 2021, 01:01 UTC
Message-ID
<20210518010121.1350327-1-felipe.contreras@gmail.com>

Our man pages don't contain many useful colors (just blue links), moreover, many people have groff SGR disabled, so they don't see any colors with man pages.

We can set LESS_TERMCAP variables to render bold and underlined text with colors in the pager; a common trick[1].

Bold is rendered as red, underlined as blue, and standout (messages and highlighted search) as inverse magenta.

This only works when the pager is less, and the color.pager configuration is enabled, as well as color.ui.

[1] https://unix.stackexchange.com/questions/119/colors-in-man-pages/147
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 builtin/help.c | 27 ++++++++++++++++++++++++++-
 color.h        |  1 +
 2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/builtin/help.c b/builtin/help.c
index bb339f0fc8..0119e833a8 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -11,6 +11,7 @@
 #include "config-list.h"
 #include "help.h"
 #include "alias.h"
+#include "color.h"
 
 #ifndef DEFAULT_HELP_FORMAT
 #define DEFAULT_HELP_FORMAT "man"
@@ -253,10 +254,33 @@ static void exec_man_konqueror(const char *path, const char *page)
 	}
 }
 
+static void colorize_man(void)
+{
+	if (!pager_use_color || !want_color(GIT_COLOR_UNKNOWN))
+		return;
+
+	/* Disable groff colors */
+	setenv("GROFF_NO_SGR", "1", 0);
+
+	/* Bold */
+	setenv("LESS_TERMCAP_md", GIT_COLOR_BOLD_RED, 0);
+	setenv("LESS_TERMCAP_me", GIT_COLOR_RESET, 0);
+
+	/* Underline */
+	setenv("LESS_TERMCAP_us", GIT_COLOR_BLUE GIT_COLOR_UNDERLINE, 0);
+	setenv("LESS_TERMCAP_ue", GIT_COLOR_RESET, 0);
+
+	/* Standout */
+	setenv("LESS_TERMCAP_so", GIT_COLOR_MAGENTA GIT_COLOR_REVERSE, 0);
+	setenv("LESS_TERMCAP_se", GIT_COLOR_RESET, 0);
+}
+
 static void exec_man_man(const char *path, const char *page)
 {
 	if (!path)
 		path = "man";
+
+	colorize_man();
 	execlp(path, "man", page, (char *)NULL);
 	warning_errno(_("failed to exec '%s'"), path);
 }
@@ -264,6 +288,7 @@ static void exec_man_man(const char *path, const char *page)
 static void exec_man_cmd(const char *cmd, const char *page)
 {
 	struct strbuf shell_cmd = STRBUF_INIT;
+	colorize_man();
 	strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 	execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 	warning(_("failed to exec '%s'"), cmd);
@@ -372,7 +397,7 @@ static int git_help_config(const char *var, const char *value, void *cb)
 	if (starts_with(var, "man."))
 		return add_man_viewer_info(var, value);
 
-	return git_default_config(var, value, cb);
+	return git_color_default_config(var, value, cb);
 }
 
 static struct cmdnames main_cmds, other_cmds;
diff --git a/color.h b/color.h
index 98894d6a17..d012add4e8 100644
--- a/color.h
+++ b/color.h
@@ -51,6 +51,7 @@ struct strbuf;
 #define GIT_COLOR_FAINT		"\033[2m"
 #define GIT_COLOR_FAINT_ITALIC	"\033[2;3m"
 #define GIT_COLOR_REVERSE	"\033[7m"
+#define GIT_COLOR_UNDERLINE	"\033[4m"
 
 /* A special value meaning "no color selected" */
 #define GIT_COLOR_NIL "NIL"
-- 
2.31.1
Next: brian m. carlson
Message 1 of 33 in “help: colorize man pages”
  1. help: colorize man pagesFelipe Contreras, May 18, 2021
  2. brian m. carlsonMay 18, 2021
  3. Felipe ContrerasMay 18, 2021
  4. brian m. carlsonMay 18, 2021
  5. Junio C HamanoMay 19, 2021
  6. brian m. carlsonMay 19, 2021
  7. Junio C HamanoMay 19, 2021
  8. Ævar Arnfjörð BjarmasonMay 19, 2021
  9. Felipe ContrerasMay 19, 2021
  10. brian m. carlsonMay 21, 2021
  11. Felipe ContrerasMay 21, 2021
  12. Igor DjordjevicMay 21, 2021
  13. Felipe ContrerasMay 21, 2021
  14. Igor DjordjevicMay 21, 2021
  15. Felipe ContrerasMay 21, 2021
  16. Igor DjordjevicMay 22, 2021
  17. Felipe ContrerasMay 22, 2021
  18. Igor DjordjevicMay 23, 2021
  19. Felipe ContrerasMay 23, 2021
  20. Igor DjordjevicMay 21, 2021
  21. Junio C HamanoMay 21, 2021
  22. Ævar Arnfjörð BjarmasonMay 19, 2021
  23. Jeff KingMay 19, 2021
  24. Felipe ContrerasMay 19, 2021
  25. Felipe ContrerasMay 19, 2021
  26. Felipe ContrerasMay 19, 2021
  27. brian m. carlsonMay 20, 2021
  28. Junio C HamanoMay 20, 2021
  29. Felipe ContrerasMay 20, 2021
  30. Junio C HamanoMay 20, 2021
  31. Felipe ContrerasMay 20, 2021
  32. Felipe ContrerasMay 20, 2021
  33. Felipe ContrerasMay 19, 2021

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