Bash: Counting instances of a string in text file with a loop

Question

I am trying to write a simple bash script in which it takes in a text file, loops through the file and tells me how many times a certain string appears in the file. I want to eventually use this for a custom log searcher (for instance, search for the words 'log in' in a particular log file, etc.), but am having some difficulty as I am relatively new to bash. I want to be able to quickly search different logs for different terms at my will and see how many times they occur. Everything works perfectly until I get down to my loops. I think that I am using grep wrong, but am unsure if that is the issue. My loop codes may seem a little strange because I have been at it for a while and have been constantly tweaking things. I have done a bunch of searching but I feel like I am the only one who has ever had this issue (hopefully not because it is incredibly simple and I just suck). Any and all help is greatly appreciated, thanks in advance everyone.

edit: I would like to account for every instance of the string and not just one instance per line

#!/bin/bash

echo "This bash script counts the instances of a user-defined string in a file."

echo "Enter a file to search:"

read fileName

echo " "

echo $path

if [ -f "$fileName" ] || [ -d "$fileName" ]; then

echo "File Checker Complete: '$fileName' is a file."
echo " "
echo "Enter a string that you would like to count the occurances of in '$fileName'."

read stringChoice
echo " "
echo "You are looking for '$stringChoice'. Counting...."

#TRYING WITH A WHILE LOOP
count=0
cat $fileName | while read line
do
    if echo $line | grep $stringChoice; then
        count=$[ count + 1 ]
done
echo "Finished processing file"




#TRYING WITH A FOR LOOP
#    count=0
#    for i in $(cat $fileName); do
#        echo $i  
#        if grep "$stringChoice"; then
#            count=$[ $count + 1 ]
#            echo $count
#        fi
#    done

if [ $count == 1 ] ; then
    echo " "
    echo "The string '$stringChoice' occurs $count time in '$fileName'."

elif [ $count > 1 ]; then
    echo " "
    echo "The string '$stringChoice' occurs $count times in '$fileName'."

fi
elif [ ! -f "$fileName" ]; then

echo "File does not exist, please enter the correct file name."

fi

I0_ol · Accepted Answer · 2016-10-15 03:36:19Z

3

To find and count all occurrences of a string, you could use grep -o which matches only the word instead of the entire line and pipe the result to wc

read string; grep -o "$string" yourfile.txt | wc -l

edited Oct 15, 2016 at 3:36

answered Oct 15, 2016 at 3:18

I0_ol

1,1192 gold badges14 silver badges32 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

brandnew958 Over a year ago

Thanks for the input. I would have preferred the answer to contain a loop, but I appreciate the help. Will note this method of doing so for future projects.

Mark Reed · Accepted Answer · 2016-10-15 03:32:15Z

0

You made basic syntax error in the code. Also, the variable of count was never updating as the the while loop was being executed in a subshell and thus the updated count value was never reflecting back.

Please change your code to the following one to get desired result.

#!/bin/bash

echo "This bash script counts the instances of a user-defined string in a file."

echo "Enter a file to search:"

read fileName

echo " "

echo $path

if [ -f "$fileName" ] ; then

        echo "File Checker Complete: '$fileName' is a file."
        echo " "
        echo "Enter a string that you would like to count the occurances of in '$fileName'."

        read stringChoice
        echo " "
        echo "You are looking for '$stringChoice'. Counting...."

#TRYING WITH A WHILE LOOP
        count=0
        while read line
        do
                if echo $line | grep $stringChoice; then
                        count=`expr $count + 1`
                fi
        done < "$fileName"
        echo "Finished processing file"
        echo "The string '$stringChoice' occurs $count time in '$fileName'."

elif [ ! -f "$fileName" ]; then
        echo "File does not exist, please enter the correct file name."
fi

edited Oct 15, 2016 at 3:32

Mark Reed

96k17 gold badges149 silver badges189 bronze badges

answered Oct 15, 2016 at 3:28

Rohit Singhal

142 bronze badges

1 Comment

brandnew958 Over a year ago

This is PERFECT! Exactly what I was looking for. The help is much appreciated.

Collectives™ on Stack Overflow

Bash: Counting instances of a string in text file with a loop

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related