BASH: Search a string and display the exact (from every character) number of times a substring happens inside it

starrysky1 · 04-26-2018, 06:38 PM

I've searched all over and still cant find this simple answer. I'm sure its so easy. Please help if you know how to accomplish this.

sample.txt is:

AAAAA

I want to find the exact times the combination "AAA" happens. If you just use for example

grep -o 'AAA' sample.txt | wc -l

We receive a 1. This is the same as just searching the number of times AAA happens from with a standard text editor search box type search. However, I want the complete number of matches exactly, starting from each individual character which is exactly 3. We get this when we search from each character individually instead of treating each AAA hit like a box type block.

I am looking for the most squeezed in/most possibilities/literal exact number of occurences starting from every individual character of "AAA" in sample.txt, not just blocks of every time it finds it like it does in a normal text editor type search from the search box.

How do we accomplish this, preferrably in AWK?

THANKS A ZILLION !!!!

danielbmartin · 04-26-2018, 07:04 PM

Please be more specific.

If your sample text is AAAAbbcccAAAdddAAAAAeee
and your search string is AAA
how many "hits" do you expect? 3? 4? 6?

Daniel B. Martin

starrysky1 · 04-26-2018, 07:53 PM

Quote:

Originally Posted by danielbmartin

Please be more specific.

If your sample text is AAAAbbcccAAAdddAAAAAeee
and your search string is AAA
how many "hits" do you expect? 3? 4? 6?

Daniel B. Martin

6! Thanks a ton, I got to a solution by using the following script.

The working solution is:

Code:

#!/bin/bash

search_term="AAA"
text=$(cat sample.txt)
term_len=${#search_term}
occurences=0

# While the text is greater than or equal to the search term length
while [ "${#text}" -ge "$term_len" ]; do

    # Look at just the length of the search term
    text_substr=${text:0:${term_len}}

    # If we see the search term, increment occurences
    if [ "$text_substr" = "$search_term" ]; then
        ((occurences++))
    fi

    # Remove the first character from the main text
    # (e.g. "AAAAA" becomes "AAAA")
    text=${text:1}
done

printf "$occurences" "$search_term"

danielbmartin · 04-26-2018, 09:21 PM

Code:

search_term="AAA"
text=$(cat $Sample)
term_len=${#search_term}
text_len=${#text}
occurences=0
j=-1
# While the text is greater than or equal to the search term length
while [ "$j" -le "$text_len" ]; do
    let j=j+1
    # Look at just the length of the search term
    text_substr=${text:$j:${term_len}}

    # If we see the search term, increment occurences
    if [ "$text_substr" = "$search_term" ]; then
        ((occurences++))
    fi
done
printf "$occurences" "$search_term"

Daniel B. Martin

.