2. In a Linux system, the dmesg command prints out kernel messages. Use the command to determine which SCSI disks the kernel attached when it started up

a=$(dmesg | grep SCSI | grep Attached | cut -d ' ' -f 8)

echo $a

answer: [sda] [sdb]

3. The df command shows you how much disk space is available on a Linux system. Use the output from the previous question to write a command pipeline that prints how much disk space is available on each of the disks found in question 1. The only acceptable output consists of two numbers only. NOTE: instead of cut, you may want to use awk. To print the second field in a whitespace-delimited file using awk, use the following command: awk '{print $2}'

error in question 3

a=$(dmesg | grep SCSI | grep Attached | cut -d ' ' -f 8)

{ nothing happens }

b=$(a:1:3)

{ a:1:3: command not found }

df | grep $b | awk '{print $4}'

4. Update the command pipeline above to add up both numbers and print only one value. If you do it right, you will only need to chain two commands!