how to search file for begin of string and save a variable

Question

i am trying to find a way of searching a file for string, it needs to work by searching then file and if any line in the file begin with what i am searching for, then take that whole line and save it as variable so i can using it later on kick off another command.

i have try this in python but i want to find a way in bash

def f(inputpara,substringpara):
   temp_log=""
   for item in inputpara.split("\n"):
    if  substringpara in item :
             temp_log=item.strip()
  return  temp_log

thanks i was able to get it working

IFS=$'\n' lines=( $(grep 'string*' textout.txt) )

    for i in "{lines[@]}"
            do
             echo ${lines[@]}
    done

Answer 1

Use grep to find the string at the start of the line and an array to save the results:

IFS=$'\n' lines=( $(grep '^string' file.txt) )

• grep '^string' file.txt finds the string string at the start of lines of file file.txt

• The array lines contains the matched lines, the IFS=$'\n' makes each line an array element

Now you can iterate over the results using regular array operations.

For example, to find the number of lines found:

${#lines[@]}

First element:

${lines[0]}

Second element:

${lines[1]}

Iterate over the elements using for loop:

for i in "{lines[@]}"; do ....; done