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
This will output the number of lines that contain your search string.
grep -c "echo" FILE
This won't, however, count the number of occurrences in the file (ie, if you have echo multiple times on one line).
edit:
After playing around a bit, you could get the number of occurrences using this dirty little bit of code:
sed 's/echo/echo\n/g' FILE | grep -c "echo"
This basically adds a newline following every instance of echo so they're each on their own line, allowing grep to count those lines. You can refine the regex if you only want the word "echo", as opposed to "echoing", for example.