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

user_1280996 0
Viewed 155566

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
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5 Answers

None of the existing answers worked for me with a single-line 10GB file. Grep runs out of memory even on a machine with 768 GB of RAM!

$ cat /proc/meminfo | grep MemTotal
MemTotal:       791236260 kB
$ ls -lh test.json
-rw-r--r-- 1 me all 9.2G Nov 18 15:54 test.json
$ grep -o '0,0,0,0,0,0,0,0,' test.json  | wc -l
grep: memory exhausted
0

So I wrote a very simple Rust program to do it.

  1. Install Rust.
  2. cargo install count_occurences
$ count_occurences '0,0,0,0,0,0,0,0,' test.json
99094198

It's a little slow (1 minute for 10GB), but at least it doesn't run out of memory!

user_2655210

if you just want the number of occurences then you can do this, $ grep -c "string_to_count" file_name

user_60482170
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