通过检查多个条件来提取字符串的一部分-Shell脚本

Question

First time I am trying any shell script, the task which I need to perform is below:

Out put of this command is below -> cat /sys/kernel/debug/spmi/spmi-0/data

00800 00 03 03 00 01 01 00 C0 10 00 00 00 00 20 00 00
00810 00 03 03 03 00 03 03 00 00 00 00 00 00 00 00 00
00820 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00830 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00840 0F 07 01 00 0F 07 04 00 0F 07 07 80 0F 07 04 00
00850 0F 07 04 00 0F 03 08 00 00 00 01 80 00 00 00 00
00860 00 00 00 80 00 00 04 80 00 00 04 00 00 00 00 00
00870 0F 00 00 00 02 04 00 00 00 00 00 00 00 00 00 00
00880 FE 00 40 00 00 00 00 00 05 00 20 00 01 00 00 00

I need to check the value of first row and 14th column value and extract it. That value either can be 00 or 20 . On the basis of that value i have to change the dir name which i think i can take care.

can any body help me out in this as i have googled from https://unix.stackexchange.com/questions/37313/how-do-i-grep-for-multiple-patterns but could not make it.

Answer 1

It is very easy!

$ head /sys/kernel/debug/spmi/spmi-0/data -n 1| cut -d " " -f 14

Explanation:

1. head /sys/kernel/debug/spmi/spmi-0/data -n 1 it will output first line from given file.

2. cut -d " " -f 14 will select 14th field/column (where fields get delimited by " " -Space

Edit

Usage

value=`head /sys/kernel/debug/spmi/spmi-0/data -n 1| cut -d " " -f 14`
echo $value

awk - solution

Alternate solution provided by twalberg

awk 'NR==1{print $14}' /sys/kernel/debug/spmi/spmi-0/data

Answer 2

Create a pattern which you need to search like in your case it's 00 or 20 as i understand. pattern="00|20"

cat /sys/kernel/debug/spmi/spmi-0/data | grep -E “${pattern}”

Then you can use cut -d " " -f2 for getting specific colum This will give the output based on your pattern, hope i understood your problem correct.