How can I count the occurrences of a string within a file?

Question

Just take this code as an example. Pretending it is an HTML/text file, if I would like to know the total number of times that echo appears, how can I do it using bash?

new_user() {     echo "Preparing to add a new user..."     sleep 2     adduser     # run the adduser program }  echo "1. Add user" echo "2. Exit"  echo "Enter your choice: " read choice   case $choice in     1) new_user     # call the new_user() function        ;;     *) exit        ;; esac  

Answer 1

The number of string occurrences (not lines) can be obtained using grep with -o option and wc (word count):

$ echo "echo 1234 echo" | grep -o echo echo echo $ echo "echo 1234 echo" | grep -o echo | wc -l 2 

So the full solution for your problem would look like this:

$ grep -o "echo" FILE | wc -l