How can i read specific line and specific field using Bash?

Question

I have this file and i want to only get the value of testme= So that i can do another action. But this throws lots of lines and actually cant yet make it work.

1. test.sh

#!/bin/bash
for i in $(cat /var/tmp/test.ini); do
  # just one output i need: value1
  grep testme= $i 
done

2. /var/tmp/test.ini

; comments
testme=value1
; comments
testtwo=value2

Answer 1

How about

#!/bin/bash

grep 'testme=' /var/tmp/test.ini | awk -F= '{ print  $2 }'

or alternatively just using bash

#!/bin/bash

regex='testme=(.*)'

for i in $(cat /var/tmp/test.ini);
do
    if [[ $i =~ $regex ]];
    then
        echo ${BASH_REMATCH[1]}
    fi
done

Answer 2

grep -v '^;' /tmp/test.ini | awk -F= '$1=="testme" {print $2}'

The grep removes comments, then awk finds the variable and prints its value. Or, same thing in a single awk line:

awk -F= '/^\s*;/ {next} $1=="testme" {print $2}' /tmp/test.ini 

Answer 3

How about this?

$ grep '^testme=' /tmp/test.ini  | sed -e 's/^testme=//' 
value1

We find the line and then remove the prefix, leaving only the value. Grep does the iterating for us, no need to be explicit.

Answer 4

I checked your codes, the problem is in your for loop.

you actually read each line of the file, and give it to grep, which is NOT correct. I guess you have many lines with error,

no such file or directory

(or something like that).

you should give grep your file name. (without the for loop)

e.g.

grep "testme=" /var/tmp/test.ini

Answer 5

awk is probably the right tool for this, but since the question does seem to imply that you only want to use the shell, you probably want something like:

while IFS== read lhs rhs; do
  if test "$lhs" = testme; then
     # Here, $rhs is the right hand side of the assignment to testme
  fi
done < /var/tmp/test.ini