17

I want to search multiple patterns in a directory containing recursive directories and files.

I know command for grep which is as follows

grep -e '(pattern1)|(pattern2)'

or

grep -r -E  'string1|string2|string3' /var/www/http

What is the command for that using ack or ag?

fedorqui
  • 275,237
  • 103
  • 548
  • 598
Sandip Pingle
  • 647
  • 2
  • 14
  • 37

4 Answers4

19

This should be enough:

ack -R 'string1|string2'

As -R is the default, you can omit it:

ack 'string1|string2'

From man ack:

-r, -R, --recurse

Recurse into sub-directories. This is the default and just here for compatibility with grep. You can also use it for turning --no-recurse off.

If you want to get the pattern from a file, say /path/to/patterns.file, you can use:

ack "$(cat /path/to/patterns.file)"

or equivallently:

ack "$(< /path/to/patterns.file)"

I cannot find an exact equivalent to grep -f.

fedorqui
  • 275,237
  • 103
  • 548
  • 598
  • What do you mean? To store the output in a file or to read the patterns from a file? Please provide the equivalent in `grep` to know exactly to what functionality you are referring to. – fedorqui Oct 09 '14 at 10:13
  • read the patterns from a file something like `grep -f pattern.txt` also if I keeping them in a file is it necessary to start pattern with some special character like `^` – Sandip Pingle Oct 09 '14 at 10:13
  • @SandipPingle uhms, I cannot find an equivalent, so I suggest getting it with `ack "$(< /path/to/patterns.file)" *`. See update. – fedorqui Oct 09 '14 at 10:21
  • 1
    `ack "$(cat /path/to/patterns.file)" *` is working fine, with by keeping patterns in file `|` separated like `pat1|pat2` – Sandip Pingle Oct 09 '14 at 10:28
  • do you know any efficient way to keep `output` also in a file currently I am using `ack "$(< /path/to/patterns.file)" * > output.txt` but problem is reading/editing `output` file is difficult. – Sandip Pingle Oct 09 '14 at 10:37
  • @SandipPingle you can maybe use `-l`, `--sort-files`, etc. It really depends on how you want the output. Take a good look at `man ack`. – fedorqui Oct 09 '14 at 10:41
  • is the `*` really needed to search in the current folder and all its subfolders ? works here without (might have been different when the question was asked, though...) – ssc Jan 26 '17 at 22:50
  • @ssc you are right, it is not necessary, like when you do `grep -R ...`. Using it does not harm because it expands to all the elements in the current dir, but at the end this is something that `-R` already does. Updated. – fedorqui Jan 27 '17 at 07:39
7

The ack command can also string along with pipes. For example the first ack finds files containing pattern1 then pipe that to another ack to search just those files for pattern2

ack -l 'pattern1' | ack -x 'pattern2'

The -l parameter means to just list the matching files (instead of the matching text). The -x parameter means to search just the files piped to it. This is similar to narrowing down the files for the next ack search. 

ack -l 'pattern1' | ack -xl 'pattern2' | ack -x 'pattern3'

This is an AND operator and not the OR operator given in the other solutions.

bkinney
  • 71
  • 1
  • 3
  • JEEZ! how often was I screwing around with `find` and `xargs` and what not when `ack` alone just does the trick, too! :+1: – ssc Jul 06 '22 at 13:19
1

For ag, as of verion 0.19.2 the default is to search in directories and files recursively.

To search for multiple patterns, you can use similiar syntax as ack

ag 'pattern1|pattern2'

will search for both pattern1 and pattern2.

In case you don't want to search recursively, you can set the search depth to 1 by the switch --depth NUM

Therefore,

ag 'pattern1|pattern2' --depth 1

will only search in the current directory for both patterns.

vincentleest
  • 925
  • 1
  • 8
  • 18
1

I don't know why but for my use case, the pipe solution didn't work.

I simply used the output of ack -l as the input to grep. For example, to quickly find all Javascript files containing string 1 and string 2:

grep "string 2" `ack -l --js "string 1"`
LondonRob
  • 73,083
  • 37
  • 144
  • 201