How to use "grep" command to find text including subdirectories

Question

I want to find all files which contain a specific string of text. The grep command works, but I don't know how to use it for every directory (I can only do it for my current directory). I tried reading man grep, but it didn't yield any help.

Answer 1

It would be better to use

grep -rl "string" /path

where

• -r (or --recursive) option is used to traverse also all sub-directories of /path, whereas
• -l (or --files-with-matches) option is used to only print filenames of matching files, and not the matching lines (this could also improve the speed, given that grep stop reading a file at first match with this option).

Answer 2

If you're looking for lines matching in files, my favorite command is:

grep -Hrn 'search term' path/to/files

• -H causes the filename to be printed (implied when multiple files are searched)
• -r does a recursive search
• -n causes the line number to be printed

path/to/files can be . to search in the current directory

Further options that I find very useful:

• -I ignore binary files (complement: -a treat all files as text)
• -F treat search term as a literal, not a regular expression
• -i do a case-insensitive search

• --color=always to force colors even when piping through less. To make less support colors, you need to use the -r option:

  grep -Hrn search . | less -r
  

• --exclude-dir=dir useful for excluding directories like .svn and .git.

Answer 3

I believe you can use something like this:

find /path -type f -exec grep -l "string" {} \;

Explanation from comments

find is a command that lets you find files and other objects like directories and links in subdirectories of a given path. If you don't specify a mask that filesnames should meet, it enumerates all directory objects.

• -type f specifies that it should process only files, not directories etc.
• -exec grep specifies that for every found file, it should run the grep command, passing its filename as an argument to it, by replacing {} with the filename

Answer 4

My default command is

grep -Rin string *

I use a capitol 'R' because ls uses it for recursive. Since grep accepts both, no reason to not use it.

EDIT: per HVNSweeting, apparently -R will follow symlinks where as -r will not.

Answer 5

If you’re willing to try something new, give ack a shot. The command to recursively search the current directory for string is:

ack string

Installation is quite simple:

curl http://betterthangrep.com/ack-standalone > ~/bin/ack && chmod 0755 !#:3

(Provided you’ve already got the directory ~/bin and it’s preferably in your PATH.)

Answer 6

The command rgrep is dedicated for such need

If not available, you can get it like this

mkdir -p ~/bin
cd ~/bin
wget http://sdjf.esmartdesign.com/files/rgrep
chmod +x rgrep

You can directly set into your default grep options as described above.

I personnaly use

[[  ${#args} -lt 5 && "${args//[[:space:]]/}" == "-i" ]] && args="-Hin"
args="${args:--Hns} --color=auto"

related topic : how to always use rgrep with color

Answer 7

grep (GNU or BSD)

You can use grep tool to search recursively the current folder with -r parameter, like:

grep -r "pattern" .

^{Note: -r - Recursively search subdirectories.}

To search within specific files, you can use a globbing syntax such as:

grep "class foo" **/*.c

^{Note: By using globbing option (**), it scans all the files recursively with specific extension or pattern. To enable this syntax, run: shopt -s globstar. You may also use **/*.* for all files (excluding hidden and without extension) or any other pattern.}

If you've the error that your argument is too long, consider narrowing down your search, or use find syntax instead such as:

find . -name "*.php" -execdir grep -nH --color=auto foo {} ';'

Alternatively use ripgrep.

ripgrep

If you're working on larger projects or big files, you should use ripgrep instead, like:

rg "pattern" .

^{Checkout the docs, installation steps or source code on the GitHub project page.}

It's much quicker than any other tool like GNU/BSD grep, ucg, ag, sift, ack, pt or similar, since it is built on top of Rust's regex engine which uses finite automata, SIMD and aggressive literal optimizations to make searching very fast.

It supports ignore patterns specified in .gitignore files, so a single file path can be matched against multiple glob patterns simultaneously.

---

You can use the common parameters such as:

• -i - Insensitive searching.
• -I - Ignore the binary files.
• -w - Search for the whole words (in opposite of partial word matching).
• -n - Show the line of your match.
• -C/--context (e.g. -C5) - Increases context, so you see the surrounding code .
• --color=auto - Mark up the matching text.
• -H - Displays filename where the text is found.
• -c - Displays count of matching lines. Can be combined with -H.

Answer 8

I do this using xargs, a very underrated command

find ./ -type f -print0 | xargs -0 grep 'string_you_are_looking_for'

find ./ gives you a recursive list of all the files in a current folder then you pipe it to xargs that executes the grep command on each one of those files

Answer 9

Update 2:

This line of commands using find and grep fixes the problem:

$ find path_to_search_in -type f -exec grep -in searchString {} 2> /dev/null +

--color=<always or auto> for colored output:

$ find path_to_search_in -type f \
            -exec grep --color=always -in searchString {} 2>/dev/null +

Example:

$ find /tmp/test/ -type f -exec grep --color=auto -in "Search string" {} 2>/dev/null +

An example run in the snapshot below:

---

Update 1:

You can try following code; as a function in your .bashrc or .bash_aliases or in a script:

wherein () 
{ 
    for i in $(find "$1" -type f 2> /dev/null);
    do
        if grep --color=auto -i "$2" "$i" 2> /dev/null; then
            echo -e "\033[0;32mFound in: $i \033[0m\n";
        fi;
    done
}

Usage: wherein /path/to/search/in/ searchkeyword

example:

$ wherein ~/Documents/ "hello world"

(Note: As suggested in the comments below by @enzotib, this doesn't work with file/directories including spaces in their names.)

---

Original post

To search for the string and output just that line with the search string:

$ for i in $(find /path/of/target/directory -type f); do \
    grep -i "the string to look for" "$i"; done

e.g.:

$ for i in $(find /usr/share/applications -type f); \
    do grep -i "web browser" "$i"; done

To display filename containing the search string:

$ for i in $(find /path/of/target/directory -type f); do \
    if grep -i "the string to look for" "$i" > /dev/null; then echo "$i"; fi; done;

e.g.:

$ for i in $(find /usr/share/applications -type f); \
    do if grep -i "web browser" "$i" > /dev/null; then echo "$i"; \
    fi; done;

Answer 10

I know there are plenty of answers here, but here's an alternative if you'd like to add other restrictions when searching the files:

find . -type f -exec grep --quiet string_to_look_for {} ';' -print

This works because grep will return 0 if it found a result, 1 otherwise. For example you can find files 1 MB large and containing something:

find . -type f -exec grep --quiet string_to_look_for {} ';' -size 1M -print

For multiple requirements you probably want to use the optimizer flag -O that exists in GNU grep.

Answer 11

A script (find-in-code) to search in C, CPP code:

#!/bin/sh

find . \( -iname "*.c" -o -iname "*.cpp" -o -iname "*.h" \) -type f -print0 | xargs -0 grep --color -n "$1"

Use:

find-in-code "search string"

Answer 12

There is a very fast alternative to grep called the Platinum Searcher. You can download it here.