Bash - while loop in a file and stop condition

Question

I want to read a specific value from a /proc file, and currently that's done in a 'while read line' loop, as a scheleton:

while read line
do
    if [[ $line = *MATCHES STRING* ]]; then
        for ((  i=0 ;  i<=$someVAR-1;  i++ ))
        do
          [if statement to check if the specific line is not equal with 0]
          then [whatever]
        done
    fi
done < "/proc/FILE"

With that, I want to further improve the loop so that I can make count of how many times the if statement inside the for loop returns a value above 0. So the stop conditions should be like:

if line matches string then
for loop
do
use a variable to keep count that the conditions has been met 2 times.

When that occurs, the loop should stop and show a message.

Increment a variable in the if statement. After the loop, test the variable, and use break to stop the loop. — Barmar
– Barmar, Commented Feb 27, 2014 at 9:52
is it possible to grep "MATCHES STRING" in the file & store result in line? — anishsane
– anishsane, Commented Feb 27, 2014 at 9:57
Hi Barmar - testing the new variable value will have to be done outside the while read line loop, so break will not work. — user3144292
– user3144292, Commented Feb 27, 2014 at 10:09
@user3144292 i think @Barmar give you solution it's vary right to increment count variable in if (inside for loop if) and check that count outside in while and use break to stop. simple — Jayesh Bhoi
– Jayesh Bhoi, Commented Feb 27, 2014 at 12:00

Barmar · Accepted Answer · 2014-02-27 12:20:31Z

1

while read line
do
    if [[ $line = *MATCHES STRING* ]]; then
        count=0
        for ((  i=0 ;  i<=$someVAR-1;  i++ ))
        do
            [if statement to check if the specific line is not equal with 0]
            then count=$((count+1))
            fi
        done
        if [[ $count -ge 2 ]]
        then break
        fi
    fi
done < "/proc/FILE"

answered Feb 27, 2014 at 12:20

Barmar

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2 Comments

user3144292 Over a year ago

Thanks a lot Barmar! I moved the if count outside the while loop as in particular I want to have it go through the entire lines and data. But again, your answer was very helpful!

Barmar Over a year ago

Your question says when that occurs, the loop should stop. How can you stop the loop if you do the test outside the loop?

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