[PATCH 1/3] tracedump: Don't use color when stdout is not a tty

[Carl Worth]

Previously, if one did an operation like:

	tracedump file.trace > file.dump

The resulting file would be cluttered with escape sequences intending
to change color. Rather than requiring the user to find the --no-color
option, we can simply not use any color escape sequences when stdout
is not a tty.
---

On Tue, 11 Oct 2011, Anuj Phogat <anuj.phogat at gmail.com> wrote:
> it also shows unnecessary escape characters due to color highlighting.
> This can be avoided by disabling color highlighting at the time of tracedump.
>
> tracedump --no-color shape.trace > tracedumpfile

And it's even easier if the tool simply doesn't use the color escapes
when redirected to a file. Just checking whether stdout is not a tty
covers this case. That's what this patch does.

We could do something even more clever by checking whether the
terminal supports the color escape sequence but that would require
mucking in the terminfo database (yuck!), or linking to a library that
does that (such as ncurses), or shelling out to a program that could
do that (such as tput). That all seems quite a bit more complicated
than this simple patch, so is perhaps not worth it just to set the
default.

-Carl

 tracedump.cpp |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/tracedump.cpp b/tracedump.cpp
index c210a0c..77d779d 100644
--- a/tracedump.cpp
+++ b/tracedump.cpp
@@ -34,9 +34,6 @@
 #include "trace_parser.hpp"
 
 
-static bool color = true;
-
-
 static void usage(void) {
     std::cout <<
         "Usage: tracedump [OPTION] [TRACE...]\n"
@@ -51,6 +48,7 @@ static void usage(void) {
 int main(int argc, char **argv)
 {
     int i;
+    bool color = isatty(1);
 
     for (i = 1; i < argc; ++i) {
         const char *arg = argv[i];
-- 
1.7.7