How can I use grep to find a word inside a folder?

In Windows, I would have done a search for finding a word inside a folder. Similarly, I want to know if a specific word occurs inside a directory containing many sub-directories and files. My searches for grep syntax shows I must specify the filename, i.e. grep string filename.

Now, I do not know the filename, so what do I do? A friend suggested to do grep -nr string, but I don't know what this means and I got no results with it (there is no response until I issue a Ctrl + C).

grep -nr 'yourString*' .

The dot at the end searches the current directory. Meaning for each parameter:

-n            Show relative line number in the file
'yourString*' String for search, followed by a wildcard character
-r            Recursively search subdirectories listed
.             Directory for search (current directory)

grep -nr 'MobileAppSer*' . (Would find MobileAppServlet.java or MobileAppServlet.class or MobileAppServlet.txt; 'MobileAppASer*.*' is another way to do the same thing.)

To check more parameters use man grep command.

grep -nr string my_directory

Additional notes: this satisfies the syntax grep [options] string filename because in Unix-like systems, a directory is a kind of file (there is a term "regular file" to specifically refer to entities that are called just "files" in Windows).

grep -nr string reads the content to search from the standard input, that is why it just waits there for input from you, and stops doing so when you press ^C (it would stop on ^D as well, which is the key combination for end-of-file).

GREP: Global Regular Expression Print/Parser/Processor/Program.
You can use this to search the current directory.
You can specify -R for "recursive", which means the program searches in all subfolders, and their subfolders, and their subfolder's subfolders, etc.

grep -R "your word" .

-n will print the line number, where it matched in the file.
-i will search case-insensitive (capital/non-capital letters).

grep -inR "your regex pattern" .

There's also:

find directory_name -type f -print0 | xargs -0 grep -li word

but that might be a bit much for a beginner.

find is a general purpose directory walker/lister, -type f means "look for plain files rather than directories and named pipes and what have you", -print0 means "print them on the standard output using null characters as delimiters". The output from find is sent to xargs -0 and that grabs its standard input in chunks (to avoid command line length limitations) using null characters as a record separator (rather than the standard newline) and then applies grep -li word to each set of files. On the grep, -l means "list the files that match" and -i means "case insensitive"; you can usually combine single character options so you'll see -li more often than -l -i.

If you don't use -print0 and -0 then you'll run into problems with file names that contain spaces so using them is a good habit.

grep -nr search_string search_dir

will do a RECURSIVE (meaning the directory and all it's sub-directories) search for the search_string. (as correctly answered by usta).

The reason you were not getting any anwers with your friend's suggestion of:

grep -nr string

is because no directory was specified. If you are in the directory that you want to do the search in, you have to do the following:

grep -nr string .

It is important to include the '.' character, as this tells grep to search THIS directory.

Why not do a recursive search to find all instances in sub directories:

grep -r 'text' *

This works like a charm.

Similar to the answer posted by @eLRuLL, an easier way to specify a search that respects word boundaries is to use the -w option:

grep -wnr "yourString" .

Another option that I like to use:

find folder_name -type f -exec grep your_text  {} \;

-type f returns you only files and not folders

-exec and {} runs the grep on the files that were found in the search (the exact syntax is "-exec command {}").

1. grep -r "yourstring" * Will find "yourstring" in any files and folders

Now if you want to look for two different strings at the same time you can always use option E and add words for the search. example after the break

2. grep -rE "yourstring|yourotherstring|$" * will search for list locations where yourstring or yourotherstring matches

The answer you selected is fine, and it works, but it isn't the correct way to do it, because:

grep -nr yourString* .

This actually searches the string "yourStrin" and "g" 0 or many times.

So the proper way to do it is:

grep -nr \w*yourString\w* .

This command searches the string with any character before and after on the current folder.

grep -R "string" /directory/

-R follows also symlinks when -r does not.

The following sample looks recursively for your search string in the *.xml and *.js files located somewhere inside the folders path1, path2 and path3.

grep -r --include=*.xml --include=*.js "your search string" path1 path2 path3

So you can search in a subset of the files for many directories, just providing the paths at the end.

Run(terminal) the following command inside the directory. It will recursively check inside subdirectories too.

grep -r 'your string goes here' * 

Don't use grep. Download Silver Searcher or ripgrep. They're both outstanding, and way faster than grep or ack with tons of options.