Re: tip: sweet grep recurse feature

From	Eli the Bearded <*@eli.users.panix.com>
Newsgroups	comp.os.linux.misc
Subject	Re: tip: sweet grep recurse feature
Date	2019-06-15 20:09 +0000
Organization	Some absurd concept
Message-ID	<eli$1906151608@qaz.wtf> (permalink)
References	<qdt7oj$1v7$1@dont-email.me> <2d2ftf-ur.ln1@Telcontar.valinor> <87pnnfvyaw.fsf@LkoBDZeT.terraraq.uk> <qe2r3g$t3l$1@news.xmission.com>

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In comp.os.linux.misc, Kenny McCormack <gazelle@shell.xmission.com> wrote:
> Richard Kettlewell  <invalid@invalid.invalid> wrote:
[I wrote upthread:]
>>>> Alternative way:
>>>> 
>>>>     find /etc/dnf -type f -exec grep xclude {} +

>> No it doesn't; it runs one instance of grep for many filenames.
> That's because of the + symbol at the end of the line, which is an
> extension that does kinda the same thing as the normal way of using xargs.

You say "extension", I say "native feature". I've used that with
versions of find not from Gnu.

> The more normal way to do this sort of thing is to pipe the output of find
> into xargs.

That breaks on, say, Solaris with filenames that include whitespace,
whereas the find I suggested just works. Solaris's find does "-exec ...  +"
but doesn't do "-print0" (to use with "| xargs -0").

> BTW, what's really wrong with the "tip" which originated this thread is
> that the following doesn't do what you expect:
> 
>     $ grep -r somestring *.c

That depends on what you expect a fileglob to do. It works if you have a
bunch of directories named (eg) foo.c, bar.c, etc.

> Yes, I understand why it does what it does and, of course, it is not a bug,
> but it is nevertheless not what you had hoped for when you typed it in.

For me, understanding that fileglobs happen in the shell, before the
command is started, that the "*" must match something that does not
begin with a dot (at least for leading *) and is in the current directory, 
came to me a very long time ago and is well in-grained in my expectation
of how things work.

> I got bit by this a few days ago (before this thread got started).  Obvious
> fix is to switch to the usual "find ...  | xargs grep" idiom.

Also in-grained in me is a knowledge that filename suffixes are
convention, not rules, in Unix land. 

    $ rm -f count
    $ mv count.c count.gif
    $ gcc -o count -x c count.gif
    $ file count.gif count
    count.gif: C source, ASCII text
    count:     ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/l, for GNU/Linux 2.6.32, BuildID[sha1]=eb042230e49538d90790c25b0a9a3d2c42fedb3d, not stripped
    $

Elijah
------
the ".c" bit is very handy for ".c.o:" rules in a Makefile

Thread

tip: sweet grep recurse feature T <T@invalid.invalid> - 2019-06-13 03:15 -0700
  Re: tip: sweet grep recurse feature Javier <invalid@invalid.invalid> - 2019-06-13 08:46 -0500
    Re: tip: sweet grep recurse feature Jean-David Beyer <jeandavid8@verizon.net> - 2019-06-13 09:51 -0400
      Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-13 09:17 -0600
    Re: tip: sweet grep recurse feature Dan Espen <dan1espen@gmail.com> - 2019-06-13 11:22 -0400
      Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-13 09:56 -0600
      Re: tip: sweet grep recurse feature Richard Kettlewell <invalid@invalid.invalid> - 2019-06-13 17:29 +0100
        Re: tip: sweet grep recurse feature Dan Espen <dan1espen@gmail.com> - 2019-06-13 15:38 -0400
          Re: tip: sweet grep recurse feature Richard Kettlewell <invalid@invalid.invalid> - 2019-06-14 09:49 +0100
            Re: tip: sweet grep recurse feature Javier <invalid@invalid.invalid> - 2019-06-14 04:39 -0500
              Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-14 12:11 +0200
                Re: tip: sweet grep recurse feature Javier <invalid@invalid.invalid> - 2019-06-14 07:11 -0500
                Re: tip: sweet grep recurse feature Jean-David Beyer <jeandavid8@verizon.net> - 2019-06-14 09:07 -0400
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-14 12:44 -0600
                Re: tip: sweet grep recurse feature Robert Heller <heller@deepsoft.com> - 2019-06-14 14:20 -0500
                Re: tip: sweet grep recurse feature Eli the Bearded <*@eli.users.panix.com> - 2019-06-15 03:18 +0000
                Re: tip: sweet grep recurse feature Robert Heller <heller@deepsoft.com> - 2019-06-14 23:05 -0500
                Re: tip: sweet grep recurse feature Anssi Saari <as@sci.fi> - 2019-06-17 09:44 +0300
                Re: tip: sweet grep recurse feature Fenris <fenris@invalid.invalid> - 2019-06-17 10:21 +0200
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-14 12:50 -0600
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-15 13:37 +0200
              Re: tip: sweet grep recurse feature Dan Espen <dan1espen@gmail.com> - 2019-06-14 08:01 -0400
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-14 12:55 -0600
                Re: tip: sweet grep recurse feature Dan Espen <dan1espen@gmail.com> - 2019-06-14 17:54 -0400
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-14 20:20 -0600
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-15 13:42 +0200
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-15 11:09 -0600
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-17 12:37 +0200
                Re: tip: sweet grep recurse feature Aragorn <thorongil@telenet.be> - 2019-06-17 12:51 +0200
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-17 12:57 +0200
                Re: tip: sweet grep recurse feature Aragorn <thorongil@telenet.be> - 2019-06-17 14:20 +0200
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-17 08:51 -0600
                Re: tip: sweet grep recurse feature Aragorn <thorongil@telenet.be> - 2019-06-17 19:43 +0200
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-17 20:38 +0200
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-17 13:07 -0600
                Re: tip: sweet grep recurse feature Aragorn <thorongil@telenet.be> - 2019-06-17 21:56 +0200
                Re: tip: sweet grep recurse feature Georges <georges@prout.com> - 2019-06-17 22:30 +0200
                Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-17 22:19 +0200
                Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-17 19:43 -0600
                Re: tip: sweet grep recurse feature Aragorn <thorongil@telenet.be> - 2019-06-18 10:26 +0200
                Re: tip: sweet grep recurse feature Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2019-06-18 23:58 +0000
            Re: tip: sweet grep recurse feature Dan Espen <dan1espen@gmail.com> - 2019-06-14 08:07 -0400
      Re: tip: sweet grep recurse feature The Natural Philosopher <tnp@invalid.invalid> - 2019-06-13 19:42 +0100
  Re: tip: sweet grep recurse feature Andreas Kohlbach <ank@spamfence.net> - 2019-06-13 14:58 -0400
    Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-13 14:29 -0600
      Re: tip: sweet grep recurse feature Andreas Kohlbach <ank@spamfence.net> - 2019-06-13 16:38 -0400
  Re: tip: sweet grep recurse feature Eli the Bearded <*@eli.users.panix.com> - 2019-06-15 03:10 +0000
    Re: tip: sweet grep recurse feature "Carlos E.R." <robin_listas@es.invalid> - 2019-06-15 13:46 +0200
      Re: tip: sweet grep recurse feature Richard Kettlewell <invalid@invalid.invalid> - 2019-06-15 13:16 +0100
        Re: tip: sweet grep recurse feature gazelle@shell.xmission.com (Kenny McCormack) - 2019-06-15 13:16 +0000
          Re: tip: sweet grep recurse feature Grant Taylor <gtaylor@tnetconsulting.net> - 2019-06-15 11:12 -0600
            Re: tip: sweet grep recurse feature Richard Kettlewell <invalid@invalid.invalid> - 2019-06-15 22:26 +0100
          Re: tip: sweet grep recurse feature Eli the Bearded <*@eli.users.panix.com> - 2019-06-15 20:09 +0000
    Re: tip: sweet grep recurse feature T <T@invalid.invalid> - 2019-06-16 14:29 -0700

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