Question

I’m trying to get specific data from the smartctl command. I want to get the total power_on_hours, but I don’t want all the filler. I just want the straight hours. This is the command I’ve come up with now:

smartctl -A /dev/sda | grep Power_On_Hours

My output is then something similar to:

9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       27

I want the last number on the line. I figure that I can probably somehow read to the end of the file and count back to the first space or search until the hyphen and read until the end of the file. I just don’t know how I would do that. My experience with grep is way too low to know how to approach this. My goal is to have the output be something like:

27

Any help would be much appreciated.

Answer 1

If you can/want to use awk it is easy to grab the last field with awk '{print $NF}'. E.g., building on what you already have:

smartctl -A /dev/sda | grep Power_On_Hours | awk '{print $NF}'

NF is the awk built-in variable for number of fields. Using the $NF means to use the contents of that field.

However, you could shorten this (and eliminate grep) by just having awk search for the string:

 smartctl -A /dev/sda | awk '/Power_On_Hours/ {print $NF}'