Home / ubuntu / Questions / 1407036
Accepted
Artur Meinild
Asked: 2022-05-07 07:58:59 +0800 CST

System Activity Report (sar) - how can I preserve color, but disable extra header lines? (and use less)

  • 772

If you run sar without parameters, the output is in color, but with extra headers inserted after each page. If you run sar | cat the extra headers are removed, but so is the coloring.

If you would like to pipe into less, running sar | less have the same effect as using cat - extra headers are removed, but so are colors. If you would like to preserve color with less, you can use unbuffer (which is installed as a part of expect) and less -R, but then the extra headers appear again.

I believe this is better shown in pictures below (the extra headers are marked in image 2).

The result of sar | less: enter image description here

The result of unbuffer sar | less -R: enter image description here

So is it at all possible to preserve colors with the sar command using less, and at the same time not have the extra header lines for each page (as marked in image 2)?

I reckon it might be possible to do this with some elaborate awk/grep/sed piping (and maybe chained commands), but I would prefer a more straight solution with the commands themselves, if this is at all possible. This is also due to the fact that I would like to pipe the result to less using a single command.

I'm using Ubuntu Server 22.04.

system

1 Answers

  1. Best Answer

    I have never used sar, but man sar mentions that sar has an environment variable whose value controls this behavior:

    S_COLORS

    By default statistics are displayed in color when the output is connected to a terminal. Use this variable to change the settings. Possible values for this variable are never, always or auto (the latter is equivalent to the default settings).

    There are various tools that change their output depending on whether they are being piped to something or just printing toa terminal and many have an always option to ensure color is used regardless. For instance, see the --color options of grep and ls. It looks like sar is using an environment variable for the same thing, so just try this:

    S_COLORS=always sar | less -R

    The -R option for less allows the preservation of colors and hyperlinks in the text being piped.

    • 2