Find Number of Occurrences of Substring in String in Bash

Bash – Find number of occurrences of substring in string

To find number of occurrences of a substring in a string in Bash scripting, you can use echo, grep, and wc command, as shown in the following expression.

echo "$str" | grep -o "$substr" | wc -l

• echo displays the given string str
• grep -o options is used to print only the matched parts, each on a separate line
• wc -l prints the newline counts

Example

In the following script, we take a string in str and substring in substr. We count the number of occurrences of substring substr in string str, using the above specified expression.

example.sh

#!/bin/bash

str="hello world as world new world"
substr="world"
count=$(echo "$str" | grep -o "$substr" | wc -l)
echo "Number of occurrences : $count"

Bash Version: GNU bash, version 5.2.15(1)-release (aarch64-apple-darwin22.1.0)

Output

sh-3.2# bash example.sh 
Number of occurrences :        3

Conclusion

In this Bash Tutorial, we learned how to find the number of occurrences of substring in given string using echo, grep, and wc commands.