[How To?] Run shell script and get output into another shell.

[Thireus]

Hi guys,

I have a simple question, I want to store the output of the following command:

sudo iotop -t 0 -C 3 | grep "load: "

As you can see it is running all the time, and we get a new line every 3sec.

I just want to store these new lines into a single variable, so I can use it into a script.

To clear the screen, and do not print lines after the others when iotop is running just delete "- C".

I DO NOT WANT TO STORE THE OUTPUT ON THE DRIVE!!!
I DO NOT WANT TO KILL IOTOP, IT MUST BE RUNNING ALL THE TIME IN BACKGROUND!!!

The idea is to do not write on the drive! Just store the output into a single variable called $Activity.

For example:

Activity=$(sudo iotop -t 0 3 | grep "load: ") &

While $Activity... do blahblah... done

But the fact is that nothing can be stored into Activity :(
So I have tried to know if something can be done to read the last output of a specified PID. But I need help on that point too :-/ I don't know how to do it.

Please help... :(

[sknake]

You're not saying what you really want to do here. You can pipe the information to a named pipe or to a remote mount and store the information there.

Obviously you are wanting to do something with the data on another terminal or with another user account... please fill us in.

[Thireus]

You're not saying what you really want to do here. You can pipe the information to a named pipe or to a remote mount and store the information there.

Obviously you are wanting to do something with the data on another terminal or with another user account... please fill us in.

Thanks a lot, that was a bit stupid :D

I'm coming back soon with my code ;)

[Thireus]

Ok, here is my code:

sudo iotop -t 0 -C 3 | grep "load: " | script.sh

script.sh:

#!/bin/sh

  while read data
  do
      echo "[$(date +"%D %T")] $data" >> log_activity.txt
  done

But nothing is read :(

[sknake]

Use /dev/stdin

sk@sk:/tmp$ echo "hello" | ./script.sh
sk@sk:/tmp$ ls
aquota.group  aquota.user  log_activity.txt  lost+found  script.sh
sk@sk:/tmp$ cat log_activity.txt
hello
sk@sk:/tmp$ cat script.sh
#!/bin/bash

cat /dev/stdin >> log_activity.txt

Also you can use tail -f /dev/stdin instead of a while () loop to read the data.

[Thireus]

SOLVED!!!

...
iotop -t 0 -C 3 | grep "load: " --line-buffered |  while read data
do
    echo "${data}"
    #Do whatever you want with ${data} here :)
done
...

:)

[sknake]

Ah that is a good approach to, nice work.

Please mark this thread as solved if you have found an answer to your problem and good luck!

[Thireus]

Done ;)

Thanks for your help too :)