How to find files in UNIX which have a multiple-line pattern? - bash

Question

I'm trying to search all files for a pattern that spans multiple lines, and then return a list of file names that match the pattern.
I'm using this line:
find . -name "$file_to_check" 2>/dir1/null | xargs grep "$2" >> $grep_out
This will create a list of files and the line the matched pattern is found on within $grep_out. The problem with this is that the search doesn't span multiple lines. I've read that grep cannot span multiple lines, so I'm looking to replace grep with sed or awk.
The only thing I think that needs to be changed is the grep. I've found that grep can't search for a pattern across multiple lines, so I'm looking to use sed or awk. When I use these commands from the terminal, I get a large printout of the file matching the pattern I've given sed. All I want is the filename, not the context of the pattern. Is there a way to retrieve this - perhaps have sed print out the filename rather than the context? Or, have sed return true/false when it finds a match, and then I can save the current filename that was used to do the search.

Answer 1

Most text processing tools are line-oriented by default. If we choose to read records as paragraphs, using blank lines as record separators:
awk -v RS= -v pattern="$2" '$0 ~ pattern {print FILENAME; exit}' file
or
find . -options ... -print0 | xargs -0 awk -v RS= -v pattern="$2" '$0 ~ pattern {print FILENAME; exit}'
I'm assuming your pattern does not contain consecutive newlines (i.e. blank lines)
To check if a file contains "word1[anything]word2[anything]word3"
brute force: read the entire file and then to a regex comparison: with bash
contents=$(< "$file")
if [[ $contents =~ "$word1".*"$word2".*"$word3" ]]; then
echo "match"
else
echo "no match"
fi
2. line-by-line with awk, use a state machine
awk -v w1="$word1" -v w2="$word2" -v w3="$word3" '
$0 ~ w1 {have_w1 = 1}
have_w1 && $0 ~ w2 {have_w2 = 1}
have_w2 && $0 ~ w3 {have_w3 = 1; exit}
END {exit (! have_w3)}
' filename
Ah, strike #2: that would match the line "word3word2word1" -- does not enforce order of the words

Answer 2

I'm trying to search all files for a pattern that spans multiple lines, and then return a list of file names that match the pattern.
pattern=$( echo "whatever your search pattern is" | tr '\n' ' ' )
for FILE in *
do
tr '\n' ' ' <"$FILE" | if grep "$pattern" then; echo $FILE; fi
done
Just replace the newlines for spaces both in your pattern and your grep-input
With 'find' , you could do it like this:
#!/bin/bash
find . -name "$file_to_check" 2>/dir1/null | while read FILE
do
tr '\n' ' ' <"$FILE" | if grep -q "word1.*word2.*word3" ; then echo "$FILE" ; fi
done >grep_out
As for the search pattern: ".*" means "any amount of any character"
Remember that a searchpattern in grep always wants to have certain characters escaped like "." becomes "\." and "^" becomes "\^"