Grep files containing two or more occurrence of a specific string

Since the question is tagged grep, here is a solution using only that utility and bash (no awk required):

#!/bin/bash for file in * do if [ "$(grep -c "Hello" "${file}")" -gt 1 ] then echo "${file}" fi done 

Can be a one-liner:

for file in *; do if [ "$(grep -c "Hello" "${file}")" -gt 1 ]; then echo "${file}"; fi; done 

###Explanation###

• You can modify the for file in * statement with whatever shell expansion you want to get all the data files.
• grep -c returns the number of lines that match the pattern, with multiple matches on a line still counting for just one matched line.
• if [ ... -gt 1 ] test that more than one line is matched in the file. If so:
• echo ${file} print the file name.

This awk will print the file name of all files with 2 or more Hello

awk 'FNR==1 {if (a>1) print f;a=0} /Hello/ {a++} {f=FILENAME} END {if (a>1) print f}' * file2 file3 

What you need is a grep that can recognise patterns across line endings ("hello" followed by anything (possibly even line endings), followed by "hello")

As grep processes your files line by line, it is (by itself) not the right tool for the job - unless you manage to cram the whole file into one single line.

Now, that is easy, for example using the tr command, replacing line endings by spaces:

if cat $file | tr '\n' ' ' | grep -q 'hello.*hello' then echo "$file matches" fi 

This is quite efficient, even on large files with many (say 100000) lines, and can be made even more efficient by calling grep with --max-count=1 , making it stop the search after a match has been found. It doesn't matter whether the two hellos are on the same line or not.

After reading your question, I think you also want to find the case hello hello in one line. ( find files where a specific string appears twice or more.) so I come up with this one-liner:

awk -v p="hello" 'FNR==1{x=0}{x+=gsub(p,p);if(x>1){print FILENAME;nextfile}}' * 

• in the above line, p is the pattern you want to search
• it will print the filename if the file contains the pattern two or more times. no matter they are in same or different lines
• during the processing, after checking some line, if we had already found two or more pattern, print the filename and stop processing current file, take the next input file, if there still are. This is helpful if you have big files.

A little test:

kent$ head f* ==> f <== hello hello world ==> f2 <== hello ==> f3 <== hello hello SK-Arch 22:27:00 /tmp/test kent$ awk -v p="hello" 'FNR==1{x=0}{x+=gsub(p,p);if(x>1){print FILENAME;nextfile}}' f* f f3 

Another way:

grep Hello * | cut -d: -f1 | uniq -d 

Grep for lines containing 'Hello'; keep only the file names; print only the duplicates.

Piping to a scripting language might be overkill, but it's oftentimes much easier than just using awk

grep -rnc "Hello" . | ruby -ne 'file, count = $_.split(":"); puts "#{file}: #{count}" if count&.to_i >= 2' 

So for your input, we get

$ grep -rnc "Hello" . | ruby -ne 'file, count = $_.split(":"); puts "#{file}: #{count}" if count&.to_i >= 2' ./2: 2 ./3: 3 

Or to omit the count

grep -rnc "Hello" . | ruby -ne 'file, _ = $_.split(":"); puts file if count&.to_i >= 2' 

grep -c Hello * | egrep -v ':[01]$' | sed 's/:[0-9]*$//'