Found a neat trick for doing recursive one-liners

ruby-talk
1

This is probably something everyone in here already knows about, but I
thought it was cool enough that I wanted to post about it.

If you want to create a one liner to say search all the *.txt files
in and under the current directory for text matching "Hello", you can do
this

find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

unfortunately that version would fail if there were any spaces in the
filenames.

2

--Cool to use throw ruby into the -exec but I would just use grep in
that scenerio.

···

On 12/26/05, Gary Watson <pfharlock@yahoo.com> wrote:

This is probably something everyone in here already knows about, but I
thought it was cool enough that I wanted to post about it.

If you want to create a one liner to say search all the *.txt files
in and under the current directory for text matching "Hello", you can do
this

find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

unfortunately that version would fail if there were any spaces in the
filenames.

3

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

Pat

···

On 12/26/05, Gary Watson <pfharlock@yahoo.com> wrote:

This is probably something everyone in here already knows about, but I
thought it was cool enough that I wanted to post about it.

If you want to create a one liner to say search all the *.txt files
in and under the current directory for text matching "Hello", you can do
this

find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

unfortunately that version would fail if there were any spaces in the
filenames.

4

Hi,

At Tue, 27 Dec 2005 12:57:53 +0900,
Gary Watson wrote in [ruby-talk:172611]:

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

unfortunately that version would fail if there were any spaces in the
filenames.

ruby -ne 'BEGIN{ARGV.replace(Dir[ARGV.join("\0")])}; print if /Hello/' '**/*.txt'

···

--
Nobu Nakada

5

ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

-a

···

On Tue, 27 Dec 2005, Gary Watson wrote:

This is probably something everyone in here already knows about, but I
thought it was cool enough that I wanted to post about it.

If you want to create a one liner to say search all the *.txt files
in and under the current directory for text matching "Hello", you can do
this

find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

--

ara [dot] t [dot] howard [at] noaa [dot] gov
all happiness comes from the desire for others to be happy. all misery
comes from the desire for oneself to be happy.
-- bodhicaryavatara

===============================================================================

6

I apologize for using a brain dead example. I was more excited about the
prospect of hitting all files under the current directory recursively, not
the actual processing I used in my examples. Thanks for the pointer to
xargs. I didn't know about that one, I'll have to take a closer look at
it's man page.

···

On Tue, 27 Dec 2005 13:05:32 +0900, Pat Maddox wrote:

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

Pat

7

Ara, I always love your examples! :slight_smile: Please keep contributing to the
community!!

BTW, I have the process management class working like a champ.. I'll
share the code with you later!

···

On 12/26/05, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:

On Tue, 27 Dec 2005, Gary Watson wrote:

> This is probably something everyone in here already knows about, but I
> thought it was cool enough that I wanted to post about it.
>
> If you want to create a one liner to say search all the *.txt files
> in and under the current directory for text matching "Hello", you can do
> this
>
> find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'
>
> I know you can do this in pure ruby in like 3 lines if you use the Find
> module, but I really wanted to do it with a one liner. Earlier I tried
> something like this
>
> ruby -ne 'print if /Hello/' `find -name '*.txt'`

   ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

-a
--

> ara [dot] t [dot] howard [at] noaa [dot] gov
> all happiness comes from the desire for others to be happy. all misery
> comes from the desire for oneself to be happy.
> -- bodhicaryavatara

8

Pat Maddox wrote:

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

Assuming you are on a machine with find, xargs, and grep, as opposed to just Ruby.

I like the idea of assembling command line utils that will work on any platform where Ruby is installed (e.g., all the machines in my house).

I also like the idea of reinventing the wheel in Ruby because sometimes you get a better wheel. Or at least one that is more hackable.

James

···

--

http://www.ruby-doc.org - Ruby Help & Documentation
Ruby Code & Style - Ruby Code & Style: Writers wanted
http://www.rubystuff.com - The Ruby Store for Ruby Stuff
http://www.jamesbritt.com - Playing with Better Toys
http://www.30secondrule.com - Building Better Tools

9

Ara,

···

On Tue, 2005-12-27 at 13:22 +0900, ara.t.howard@noaa.gov wrote:

On Tue, 27 Dec 2005, Gary Watson wrote:

> This is probably something everyone in here already knows about, but I
> thought it was cool enough that I wanted to post about it.
>
> If you want to create a one liner to say search all the *.txt files
> in and under the current directory for text matching "Hello", you can do
> this
>
> find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'
>
> I know you can do this in pure ruby in like 3 lines if you use the Find
> module, but I really wanted to do it with a one liner. Earlier I tried
> something like this
>
> ruby -ne 'print if /Hello/' `find -name '*.txt'`

   ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

That doesn't seem to do anything . .

Phil.
--
Philip Rhoades

Pricom Pty Limited (ACN 003 252 275 ABN 91 003 252 275)
GPO Box 3411
Sydney NSW 2001
Australia
Mobile: +61:(0)411-185-652
Fax: +61:(0)2-8221-9599
E-mail: phil@pricom.com.au

10

Hi --

This is probably something everyone in here already knows about, but I
thought it was cool enough that I wanted to post about it.

If you want to create a one liner to say search all the *.txt files
in and under the current directory for text matching "Hello", you can do
this

find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'

I know you can do this in pure ruby in like 3 lines if you use the Find
module, but I really wanted to do it with a one liner. Earlier I tried
something like this

ruby -ne 'print if /Hello/' `find -name '*.txt'`

ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

We've strayed a little from the original thing, but along those lines
you could also do:

  ruby -e 'puts Dir["**/**"].grep(/a\.rb/)'

(just guessing about the \. part :slight_smile:

or maybe even:

   ruby -e 'puts Dir["**/*a.rb*/"]

David

···

On Tue, 27 Dec 2005, ara.t.howard@noaa.gov wrote:

On Tue, 27 Dec 2005, Gary Watson wrote:

--
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!

11

In article
<810a540e0512262005s3e4c971bl2f2915954c34965f@mail.gmail.com>,

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files.

<educational type="but not ruby related">
Not quite. For better (maximum?) robustness, pass '-print0' to find and
'-0' to xargs. That will handle filenames with spaces and/or quotes
correctly. (If your filenames have bytes with binary value zero in them,
you still will be out of luck)
</educational>

Reinder

···

Pat Maddox <pergesu@gmail.com> wrote:

12

find . -regex '.*\.txt' -print0 | xargs -0 -n1000 grep Hello

-print0 and -0 to avoid trouble with spaces and other metagubbins.
-n1000 for a bit of a speedup
-regex to show you can :wink:

···

On Tue, 27 Dec 2005, Pat Maddox wrote:

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

13

Pat Maddox wrote:

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

Pat

et@adel:/tmp/rb$ touch 'foo bar.txt'
et@adel:/tmp/rb$ find . -name "*.txt"
../foo bar.txt
et@adel:/tmp/rb$ find . -name "*.txt" | xargs grep Hello
grep: ./foo: No such file or directory
grep: bar.txt: No such file or directory
et@adel:/tmp/rb$ find . -name "*.txt" -print0 | xargs -0 grep Hello
et@adel:/tmp/rb$

Watch out if you are using xargs. It can get pretty nasty, especially if there is not grep at work, but rm or alike.

Shooting yourself in the foot 101:
$ touch "foo .. bar -rf moo.o"
$ find . -name '*.o' | xargs rm
*BAM*

If you are using find and xargs, always use -print0 and -0, respectively.

Regards,
Stefan

14

I know Im a n00b, but I think more than anything, its good to see you so excited about Ruby. Learning new things really is fun in Ruby.

···

On Mon, 26 Dec 2005 20:22:52 -0800, Gary Watson <pfharlock@yahoo.com> wrote:

I apologize for using a brain dead example. I was more excited about the
prospect of hitting all files under the current directory recursively, not
the actual processing I used in my examples. Thanks for the pointer to
xargs. I didn't know about that one, I'll have to take a closer look at
it's man page.

On Tue, 27 Dec 2005 13:05:32 +0900, Pat Maddox wrote:

Or you can use the tools designed for finding stuff :slight_smile:

find . -name "*.txt" | xargs grep Hello

That version will work for all files. You can play with find to match
any file you want.

Pat

--
Using Opera's revolutionary e-mail client: Opera Web Browser | Faster, Safer, Smarter | Opera

15

I really prefer the simple variant...
ruby -e 'puts Dir["**/a*.{rb}"]'

finds all .rb that start with 'a', recursive of course :slight_smile:

···

Am Dienstag, 27. Dezember 2005 11:36 schrieb dblack@wobblini.net:

Hi --

On Tue, 27 Dec 2005, ara.t.howard@noaa.gov wrote:
> On Tue, 27 Dec 2005, Gary Watson wrote:
>> This is probably something everyone in here already knows about, but I
>> thought it was cool enough that I wanted to post about it.
>>
>> If you want to create a one liner to say search all the *.txt files
>> in and under the current directory for text matching "Hello", you can do
>> this
>>
>> find -name '*.txt' -exec ruby -ne 'print if /Hello/' '{}' ';'
>>
>> I know you can do this in pure ruby in like 3 lines if you use the Find
>> module, but I really wanted to do it with a one liner. Earlier I tried
>> something like this
>>
>> ruby -ne 'print if /Hello/' `find -name '*.txt'`
>
> ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

We've strayed a little from the original thing, but along those lines
you could also do:

  ruby -e 'puts Dir["**/**"].grep(/a\.rb/)'

(just guessing about the \. part :slight_smile:

or maybe even:

   ruby -e 'puts Dir["**/*a.rb*/"]

David

16

Reinder Verlinde <reinder@verlinde.invalid> writes:

<educational type="but not ruby related">
Not quite. For better (maximum?) robustness, pass '-print0' to find and
'-0' to xargs. That will handle filenames with spaces and/or quotes
correctly. (If your filenames have bytes with binary value zero in them,
you still will be out of luck)
</educational>

Know an OS where that is allowed?

···

Reinder

--
Christian Neukirchen <chneukirchen@gmail.com> http://chneukirchen.org

17

then you probably don't have any files named 'a.rb' under the current
directory - i seem to have several hundred :wink:

cheers.

-a

···

On Tue, 27 Dec 2005, Philip Rhoades wrote:

   ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

That doesn't seem to do anything . .

--

ara [dot] t [dot] howard [at] noaa [dot] gov
all happiness comes from the desire for others to be happy. all misery
comes from the desire for oneself to be happy.
-- bodhicaryavatara

===============================================================================

18

Great!

Would any mad enough rubyists start the equivalent of
http://ppt.perl.org/? For the impatient, "perl power tools: unix
reconstruction project" is an on-going attempt at writing (most of) the
BSD command set in Perl.

Not quite as mad as BASIC in TeX, but potentially useful indeed.

--DCA

19

NT 4 kernel mode API is quite happy with \0 in filenames. But it *really* confuses the Win32 layer! Haven't played with later versions...

···

On Wed, 28 Dec 2005, Christian Neukirchen wrote:

Reinder Verlinde <reinder@verlinde.invalid> writes:

<educational type="but not ruby related">
Not quite. For better (maximum?) robustness, pass '-print0' to find and
'-0' to xargs. That will handle filenames with spaces and/or quotes
correctly. (If your filenames have bytes with binary value zero in them,
you still will be out of luck)
</educational>

Know an OS where that is allowed?

20

Hi --

···

On Wed, 28 Dec 2005, ara.t.howard@noaa.gov wrote:

On Tue, 27 Dec 2005, Philip Rhoades wrote:

   ruby -e' puts Dir["**/**"].select{|e| e =~ /a.rb/} '

That doesn't seem to do anything . .

then you probably don't have any files named 'a.rb' under the current
directory - i seem to have several hundred :wink:

Or abrb, or acrb, or airbag, or.... :slight_smile:

David

--
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!