Chain grep commands to search for a pattern inside files that match another pattern - bash

Question

How can I chain multiple grep commands?
For example, if I want to search recursively for all PHP files that are publicly accessible, i.e those which contain $_user_location = 'public; and search for "SendQueue() inside all these files, what should I do?
Few of my failed attempts :
grep -rnw ./* -e "^.*user_location.*public" *.php | grep -i "^.*SendQueue().*" --color
grep -rnw ./* -e "^.*user_location.*public" *.php | xargs -0 -i "^.*SendQueue().*" --color

Answer 1

Print grep results with filename, extract filenames and pass those filenames to second grep.
grep -H ..... | cut -d: -f1 | xargs -d'\n' grep ....
Works as long as there are no : in filenames and usually there are none.
You could always do a plain old loop:
for i in *.php; do
if grep -q .... "$i"; then
grep .... "$i"
fi
done

Answer 2

Using awk:
$ awk '
/SendQueue\(\)/ { # hash all SendQueue() containing records
a[++i]=$0
}
/.*user_location.*public/ { # if condition met, flag up
f=1
}
END {
if(f) # if flag up
for(j=1;j<=i;j++) # output all hashed records
print a[j]
}' file
Testfile:
$_user_location = 'public;
SendQueue()
In the lack of sample output you only get:
SendQueue()
For multiple files:
$ for f in *.php ; do awk ... $f ; done

Answer 3

If you add -l option to your first grep, you'll get all the file names which you can feed to you second grep, like :
grep -i "^.*SendQueue().*" --color $(grep -l ...)
assuming you don't have special characters in file names.

Answer 4

Some alternative, could be quicker...
1. Using sed
sed -s '/\(SendQueue()\|_user_location = \o47public\)/H;${ x;s/\n/ /g;/SendQueue.*_user_location\|_user_location.*SendQueue/F;};d' *.php
Could by write:
sed -s '
/\(SendQueue()\|_user_location = \o47public\)/H;
${
x;
s/\n/ /g;
/SendQueue.*_user_location\|_user_location.*SendQueue/F;
};
d' *.php
Or with find:
find /path -type f -name '*.php' -exec sed -s '
/\(SendQueue()\|_user_location = \o47public\)/H;
${
x;
s/\n/ /g;
/SendQueue.*_user_location\|_user_location.*SendQueue/F;
};
d' {} +
2. Using grep
But reading each file only 1 time
grep -c "\(SendQueue()\|_user_location = 'public\)" *.php | grep :2$
or
grep -c "\(SendQueue()\|_user_location = 'public\)" *.txt | sed -ne 's/:2$//p'
Then
find /path -type f -name '*.php' -exec grep -c \
"\(SendQueue()\|_user_location = 'public\)" {} + |
sed -ne 's/:2$//p'
Of course, this work only if you're sure all sentence could be present only once.
Remark
To ensure no commented line will polute result, you could replace regex by
"^[^#/]*\(SendQueue()\|_user_location = 'public\)"
In all submited alternatives

Answer 5

I can mention two ways of doing this:
POSIX way
You can use find(1) in order to do recursive search. find is defined by POSIX and is most likely included in your system.
find . -type f -name '*.php' -exec grep -q "\$_user_location.*=.*'public" {} \; -exec grep 'SendQueue()' {} +
Here is the explanation for what this command does:
-type f Look for files
-name '*.php With the suffix .php
-exec grep -q ... {} \; Run the first grep sequence individually.
-exec grep {} + Run the second grep sequence on the files that were matched previously.
Ripgrep way
ripgrep is a really fast recursive grep tool. This will take much less search time, but you will need to obtain it separately.
rg --glob '*.php' -l "\$_user_location.*=.*'public" | xargs rg 'SendQueue\(\)'
Here is the explanation for what this command does:
--glob '*.php' Only looks inside files with the suffix .php
-l Only lists files that match
We enter the first query and pipe all the matching files to xargs
xargs runs rg with the second query and adds the received files as arguments so that ripgrep only searches those files.
Which one to use
ripgrep really shines on huge directories, but it really isn't necessary otherwise for what you are asking. Picking find is enough for most cases. The time you will spend obtaining ripgrep will probably be more than the time you will save by using it for this specific operation. ripgrep is a really nice tool regardless.
EDIT:
The find command has 2 -exec options:
-exec grep (...) {} \; This calls the grep command for each file match. This will run the following:
grep (query) file1.php
grep (query) file2.php
grep (query) file3.php
find tracks the command result for each file, and passes them to the next test if they succeed.
-exec grep (...) {} + This calls the command with all the files attached as arguments. This will expand as:
grep (query) file1.php file2.php file3.php