如何使用 bash shell 脚本读取文件中的特定单词并存储在 arrays

Question

i am new to linux and bash, here is my question:

my file (dff.v) has following lines

input a,b;
input [2:0] c;
output [2:0] d;

I have to read the file and store input variables(a,b,[2:0] c) and output variables ([2:0] d) in two different arrays,so that i can use them for further processing. I have tried below code to store input variables but i am not getting it as expected.

#!/bin/bash
#assume same directory of file
counta=0;
IFS=','
for i in $(grep -w input dff.v|sed 's/[ ]//1'|sed 's/[;]//g' | sed 's/input//g');
do
 x""$counta"=$i;
 echo $i
 ((counta=counta+1))
done 

i thought the variables will be stored as x0,x1,x2... please help!!

Answer 1

You want to dynamically create vars? It's imposible this way x"$counta"=$i , but there are some tricks that may help:

read x"$counta" <<< "$i"

Or

printf -v x"$counta" "$i"

Or

declare x"$counta"="$i"

But i'd suggest use arrays instead:

while read name value; do
    value=${value//[\[\];]}
    case $name in
        input ) input+=("$value");;
        output) output+=("$value");;
    esac
done < dff.v

echo "input:  ${input[@]}"
echo "output: ${output[@]}"

$ ./test
input:  a,b 2:0 c
output: 2:0 d

Answer 2

Given the file diff.v and it's content.

baz
input a,b;
blah
input [2:0] c;
foo
output [2:0] d;
more

---

With a while read loop, and remove the strings that your sed is removing.

#!/usr/bin/env bash

i=0
while read -r input_output lines; do
  [[ $input_output == @(input|output) ]] || continue
  lines=${lines//[][;]}
  printf -v x$i '%s' "$lines"
  ((i++))
done < diff.v

printf '%s\n' "$x0" "$x1" "$x2"

---

The output

a,b
2:0 c
2:0 d

---

Storing the values in an associative array.

#!/usr/bin/env bash

i=0
while read -r input_output lines; do
  [[ $input_output == @(input|output) ]] || continue
  lines=${lines//[][;]}
  declare -A array["x$i"]="$lines"
  ((i++))
done < diff.v

printf '%s\n' "${array[x0]}" "${array[x1]}" "${array[x2]}"

Although if you just want to have a quick check what is the value of the array.

declare -p array