On 8/15/18 3:06 AM, Phil Sutter wrote:
> Add an additional prerequisite to check_enable_color() to make sure
> stdout actually points to an open TTY device. Otherwise calls like
>
> | ip -color a s >/tmp/foo
>
> will print color escape sequences into that file.
>
> Signed-off-by: Phil Sutter <p...@nwl.cc>
> ---
> lib/color.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/color.c b/lib/color.c
> index edf96e5c6ecd7..500ba09682697 100644
> --- a/lib/color.c
> +++ b/lib/color.c
> @@ -3,6 +3,7 @@
> #include <stdarg.h>
> #include <stdlib.h>
> #include <string.h>
> +#include <unistd.h>
> #include <sys/socket.h>
> #include <sys/types.h>
> #include <linux/if.h>
> @@ -79,7 +80,7 @@ void enable_color(void)
>
> int check_enable_color(int color, int json)
> {
> - if (color && !json) {
> + if (color && !json && isatty(fileno(stdout))) {
> enable_color();
> return 0;
> }
>
This also disables color sequence when the output is piped to a pager
such as less which with the -R argument can handle it just fine.
ie., the user needs to remove the color arg when that output is not wanted.
