How to input parameters and add Columns?

Shell Programming and Scripting
1

Hello and good day

I am not familiar with programming. I have text files and I would like to:

1) edit script to input "a" and "b" parameters by users

2)put input directories in loop :
Something like this:
Ex: For i in /usr/desktop/input/SG*

3)add 2 more columns and performing arithmetic operations.

4)add name to column

(my files start with SG; Ex: "SG140101120000.CAP5xyz.txt" )

I found this script, but it is not complete.

#! /bin/bash
echo "a value"
read a 
echo "b value"
read b
For i in SG*;
do
awk '{$6=($1-64)/2 ;$7=((10^($6/10))/$a)^(1/$b) ; print}' OFS="\t" $i > /root/Desktop/decoder/output_gr_ubrb/1/$i.txt;
done

Orginal txt file:

$1      $2            $3             $4
74   3.99166 101.37082  2.000
74   3.99166 101.37834  2.000
75   3.98416 101.37082  2.000
75   3.98416 101.37834  2.000
81   3.96916 101.29571  2.000
  0   3.96166 101.28820  2.000
 82   3.96166 101.29571  2.000
 85   3.96167 101.31073  2.000

Expected result:

$1         $2             $3                $4                  $5        $6
74	3.99166	101.37082	2.000		5	0.0748783
74	3.99166	101.37834	2.000		5	0.0748783
75	3.98416	101.37082	2.000		5.5	0.0804649
75	3.98416	101.37834	2.000		5.5	0.0804649
81	3.96916	101.29571	2.000		8.5	0.12391
0	3.96166	101.28820	2.000		-32	0.000364633
82	3.96166	101.29571	2.000		9	0.133155
85	3.96167	101.31073	2.000		10.5	0.165237

Thanks in advance

2

To use shell variables inside awk program, use awk variable assignment feature:

awk -v A="$a" -v B="$b" '{$6=($1-64)/2 ;$7=((10^($6/10))/A)^(1/B) ; print}' OFS="\t"
1 Like
3

Yesssss. The first problem has beeen solved. I appreciate your help. Thank you so much Yoda.