How can I grep recursively, but only in files with certain extensions?

Question

I'm working on a script to grep certain directories:

{ grep -r -i CP_Image ~/path1/;
grep -r -i CP_Image ~/path2/;
grep -r -i CP_Image ~/path3/;
grep -r -i CP_Image ~/path4/;
grep -r -i CP_Image ~/path5/; }
| mailx -s GREP email@domain.example

How can I limit results only to extensions .h and .cpp?

Use [The Silver Searcher](https://github.com/ggreer/the_silver_searcher): `ag -i CP_Image ~/path[1-5] | mailx -s GREP email@domain.com`. Job done. — johnsyweb, Oct 09 '13 at 17:25
possible duplicate of [grep --exclude/--include syntax (do not grep through certain files)](http://stackoverflow.com/questions/221921/grep-exclude-include-syntax-do-not-grep-through-certain-files) — johnsyweb, Oct 09 '13 at 17:48
Use egrep (is most likely pre-installed on your system), and then you can use a regex. — Dogweather, Oct 09 '13 at 17:53
The GNU guys really messed up when they added `-r` to `grep` to have it search for files as that breaks the UNIX mantra of having tools that "do one thing and do it well". There's a perfectly good tool for finding files with a VERY obvious name. — Ed Morton, Oct 09 '13 at 17:58
@Dogweather , `egrep` has been deprecated for a long time. From `grep`'s man page: `Direct invocation as either egrep or fgrep is deprecated, but is provided to allow historical applications that rely on them to run unmodified.` To achieve the same result, one must use `grep -E` — mrbolichi, Apr 18 '18 at 11:03

score 1879 · Accepted Answer · edited Jun 20 '22 at 09:27

1879

Just use the --include parameter, like this:

grep -inr --include \*.h --include \*.cpp CP_Image ~/path[12345] | mailx -s GREP email@domain.example

That should do what you want.

To take the explanation from HoldOffHunger's answer below:

grep: command
-r: recursively
-i: ignore-case
-n: each output line is preceded by its relative line number in the file
--include \*.cpp: all *.cpp: C++ files (escape with \ just in case you have a directory with asterisks in the filenames)
./: Start at current directory.

edited Jun 20 '22 at 09:27

Stephen Ostermiller

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answered Sep 20 '12 at 16:35

Nelson

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@Hong where is the documentation that -R is for symbolic links? – titus Jan 20 '16 at 13:46
Can someone explain why this syntax works as opposed to what's described in the man page `--include=GLOB` – But those new buttons though.. Jan 21 '16 at 16:15
11

This example seems to have a high score because it covers such a wide range of possibilites but the answer given below of grep -r --include=*.txt 'searchterm' ./ really explains the essence of the answer – David Casper Jan 27 '17 at 01:44
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why not use double quotes instead of backslash? e.g: `grep -r -i --include="*.h" --include="*.cpp" CP_Image ` – pambda Apr 11 '17 at 05:15
@nelson How would you change this to just return all file extensions – Daniel Kaplan Jul 10 '19 at 23:35
Did *not* answer the question! Jasmine asked for *two* file types in a single search! – John Oct 25 '22 at 02:05

HoldOffHunger · Answer 2 · 2020-06-17T04:04:32.767

441

Some of these answers seemed too syntax-heavy, or they produced issues on my Debian Server. This worked perfectly for me:

grep -r --include=\*.txt 'searchterm' ./

...or case-insensitive version...

grep -r -i --include=\*.txt 'searchterm' ./

grep: command
-r: recursively
-i: ignore-case
--include: all *.txt: text files (escape with \ just in case you have a directory with asterisks in the filenames)
'searchterm': What to search
./: Start at current directory.

Source: PHP Revolution: How to Grep files in Linux, but only certain file extensions?

edited Jun 17 '20 at 04:04

answered Feb 08 '16 at 22:46

HoldOffHunger

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You should escape the `*` using `\*.cpp` or `'*.cpp'`. Otherwise it won’t give the expected result when the working directory contains some `*.txt` files. – Melebius Jan 02 '17 at 07:17
@Melebius can you explain why it needs escaping - does it have anything to do with the CPP or TXT extensions you mentioned? Or did you just use those as examples? – Simon East Apr 28 '17 at 03:05
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@SimonEast These extensions are those used in this question and answer, nothing special otherwise. It would probably work without escaping when using `--include=` but it is important to escape `*` with `--include ` (a space instead of `=`) which feels very similar otherwise. – Melebius Apr 28 '17 at 06:55
@Melebius adding to what you wrote, it does work with `--include=`. It also works with `--include`, so long as there are no files matching the pattern in the current directory. I.e., it's safest to escape the pattern when you're not using the `=` syntax, but you can live dangerously if you assume there are no files matching the pattern in the current directory. – TooTone Nov 04 '21 at 22:02
Did *not* answer the question! Jasmine asked for *two* file types in a single search! – John Oct 25 '22 at 02:05

score 91 · Answer 3 · edited Mar 23 '16 at 15:15

91

grep -rnw "some thing to grep" --include=*.{module,inc,php,js,css,html,htm} ./

edited Mar 23 '16 at 15:15

Community

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answered Jul 23 '15 at 19:38

Yuri Malov

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grep -rn "some thing to grep" --include=*.{module,inc,c,h} * – ashish Aug 04 '15 at 11:12
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Nice answer. Cleaner than the accepted on IMO but you should add search criteria as @ashish noted – But those new buttons though.. Jan 21 '16 at 16:20
why is `--include` option after needle, not with other options? – vladkras Sep 16 '16 at 12:21
@vladkras, what do you mean needle? Is it `--`? – heretoinfinity Jan 07 '20 at 22:37
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Almost, but that didn't work for me--it kept trying to match on `--include=*.foo`. The working solution was wrapping the `--include` value in quotes. E.g. `--include="*.foo"`. – Alan Hape Mar 03 '21 at 16:39
@AlanHape `*` is a special character in shells: https://stackoverflow.com/a/2755806 – Joel Mellon Jun 04 '21 at 23:11
Good answer, but it will not work with only 1 extension like `--include=*.{php}` – ViliusL Jul 29 '21 at 05:59
Just like include is there a way to exclude list of extensions? – Ammad Aug 17 '23 at 20:26

score 62 · Answer 4 · edited Apr 24 '21 at 21:09

62

Use:

find . -name '*.h' -o -name '*.cpp' -exec grep "CP_Image" {} \; -print

edited Apr 24 '21 at 21:09

Peter Mortensen

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answered Sep 20 '12 at 16:33

Amir Afghani

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i'd suggest grouping those `-name` arguments. strange things can happen if you don't. `find . \( -name '*.h' -o -name '*.cpp' \) -exec grep "CP_Image" {} \; -print` – nullrevolution Sep 20 '12 at 21:13
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use with additional "-type f" to ignore all directory objects, only interested in files. – kensai Mar 18 '17 at 12:32
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I used this method for years and it works but it's a LOT slower than recursive grep since find's exec spawns a separate grep process for each file to be searched. – beaudet Jan 08 '18 at 19:00
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Addressing @beaudet's comment, `find` can optionally bundle arguments, reducing invocations of the called process to a minimum. `find . \( -name \*.h -o -name \*.cpp \) -exec grep -H CP_Image {} +` This is suggested but not highlighted in @fedorqui's answer below and is a worthwhile improvement. The `-H` argument to grep here is useful when find only identifies a single matching file. This could eliminate the usage of `-print` in the answer. If your total list of files is sufficiently small, using a recursive shell glob (eg. `{path1,path2}/**/*.{cpp,h}`) might be preferable. – Malcolm Feb 22 '19 at 09:51

score 36 · Answer 5 · edited Apr 24 '21 at 21:12

36

There isn't any -r option on HP and Sun servers, but this way worked for me on my HP server:

find . -name "*.c" | xargs grep -i "my great text"

-i is for case insensitive search of string.

edited Apr 24 '21 at 21:12

Peter Mortensen

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answered Dec 11 '15 at 15:14

Sam B

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I've come across several servers for web hosting companies that do not have the --include option available for fgrep and this is the command line that I use in those instances. – Borgboy Jan 18 '16 at 21:30
The --include option is also not available when using Git for Windows (MinGW/MSys). – Darren Lewis Jan 19 '16 at 14:21
@DarrenLewis available in Git Bash for Windows. But strangely, it adds colorful aliases like `ll` but does not add `--color=auto` to grep. – Xeverous Dec 28 '17 at 17:28
This should be the accepted answer for completeness, portability, and brevity! – Grant Foster Jan 09 '19 at 20:30
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Re *"HP and Sun servers"*: Do you mean for [HP-UX](https://en.wikipedia.org/wiki/HP-UX) and [Solaris](https://en.wikipedia.org/wiki/Solaris_%28operating_system%29)? – Peter Mortensen Apr 24 '21 at 21:13
When there is a space character in the file name, it would be treated as two file names. Any solution to solve this problem? – hyz Dec 24 '21 at 07:54
@hyz Use `find ... -exec grep "string" {} +` (or `\;` instead of `+` at the end if your `find` is too old to support `+`). See also https://mywiki.wooledge.org/BashFAQ/020 – tripleee May 15 '22 at 05:27

score 21 · Answer 6 · edited Jun 20 '22 at 09:28

21

This answer is good:

grep -r -i --include \*.h --include \*.cpp CP_Image ~/path[12345] | mailx -s GREP email@domain.example

But it can be updated to:

grep -r -i --include \*.{h,cpp} CP_Image ~/path[12345] | mailx -s GREP email@domain.example

Which can be simpler.

edited Jun 20 '22 at 09:28

Stephen Ostermiller

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answered Jan 31 '18 at 02:37

hao

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What does *"The below answer"* refer to? References to relative positions of answers are not reliable as they depend on the view (votes/oldest/active) and changing of the accepted answer and change over time (for votes, active, and accepted state). Please respond by [editing your answer](https://stackoverflow.com/a/48533603/63550), not here in comments (***without*** "Edit:", "Update:", or similar - the answer should appear as if it was written today). – Peter Mortensen Apr 24 '21 at 21:21
Can we simply use grep command along with ls command? – Harsha Oct 27 '21 at 15:30
@Harsha Sure. use pipe to make the output of ls as the input of grep. such as ls | grep *.h – hao Dec 25 '21 at 12:26
Could you provide me a link that would give explanations as to how I can fully understand this? – Harsha Dec 26 '21 at 10:43
@Harsha https://docs.oracle.com/cd/E19504-01/802-5826/6i9iclf5k/index.html – hao Dec 27 '21 at 03:37
note: you can combine single-letter options. `grep -r -i` is the same as `grep -ri`. I mention this because I often like to use other options like '-n' and '-H' so this becomes `grep -Hinr --include ...` – gMale Jun 15 '22 at 19:01

score 14 · Answer 7 · edited May 23 '17 at 11:33

Since this is a matter of finding files, let's use find!

Using GNU find you can use the -regex option to find those files in the tree of directories whose extension is either .h or .cpp:

find -type f -regex ".*\.\(h\|cpp\)"
#            ^^^^^^^^^^^^^^^^^^^^^^^

Then, it is just a matter of executing grep on each of its results:

find -type f -regex ".*\.\(h\|cpp\)" -exec grep "your pattern" {} +

If you don't have this distribution of find you have to use an approach like Amir Afghani's, using -o to concatenate options (the name is either ending with .h or with .cpp):

find -type f \( -name '*.h' -o -name '*.cpp' \) -exec grep "your pattern" {} +
#            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

And if you really want to use grep, follow the syntax indicated to --include:

grep "your pattern" -r --include=*.{cpp,h}
#                      ^^^^^^^^^^^^^^^^^^^

I needed a script which returned exit status 1 if the grep command matched any files. I started out using find+xargs+grep. But the fact that xargs returns exit status 123 if grep returns 1 made things more complicated. It was more straightforward to just use grep in my case. — Guildenstern, Mar 10 '22 at 09:16

score 11 · Answer 8 · edited Apr 24 '21 at 21:15

11

The easiest way is:

find . -type  f -name '*.extension' 2>/dev/null | xargs grep -i string

Add 2>/dev/null to kill the error output.

To include more file extensions and grep for password throughout the system:

find / -type  f \( -name '*.conf' -o -name "*.log" -o -name "*.bak" \) 2>/dev/null |
xargs grep -i password

edited Apr 24 '21 at 21:15

Peter Mortensen

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answered Feb 05 '17 at 17:30

user3640130

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score 5 · Answer 9 · edited Apr 24 '21 at 21:18

5

ag (the silver searcher) has pretty simple syntax for this

       -G --file-search-regex PATTERN
          Only search files whose names match PATTERN.

so

ag -G *.h -G *.cpp CP_Image <path>

edited Apr 24 '21 at 21:18

Peter Mortensen

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answered May 10 '17 at 13:57

Eldamir

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using ag 2.2.0, i needed to put my flags last: `ag _string_to_find_ -G _filename_regex_` – ryanrain Apr 20 '20 at 13:31

score 2 · Answer 10 · edited Apr 24 '21 at 21:10

2

You should write "-exec grep " for each "-o -name ":

find . -name '*.h' -exec grep -Hn "CP_Image" {} \; -o -name '*.cpp' -exec grep -Hn "CP_Image" {} \;

Or group them by ( )

find . \( -name '*.h' -o -name '*.cpp' \) -exec grep -Hn "CP_Image" {} \;

Option '-Hn' shows the file name and line.

edited Apr 24 '21 at 21:10

Peter Mortensen

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answered Nov 10 '14 at 02:09

where23

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score 1 · Answer 11 · edited Apr 24 '21 at 21:10

1

Here is a method I normally use to find .c and .h files:

tree -if | grep \\.[ch]\\b | xargs -n 1 grep -H "#include"

Or if you need the line number as well:

tree -if | grep \\.[ch]\\b | xargs -n 1 grep -nH "#include"

edited Apr 24 '21 at 21:10

Peter Mortensen

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answered Mar 13 '15 at 11:17

Tom

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score 0 · Answer 12 · answered Oct 09 '20 at 20:44

0

If you want to filter out extensions from the output of another command e.g. "git":

files=$(git diff --name-only --diff-filter=d origin/master... | grep -E '\.cpp$|\.h$')

for file in $files; do
    echo "$file"
done

answered Oct 09 '20 at 20:44

nvd

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How can I grep recursively, but only in files with certain extensions?

12 Answers12

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