[ubuntu-florida] Avoid That grep Command in grep Output

[j.e.aneiros]

On Wed, Sep 15, 2010 at 10:37 AM, Miano, Steven M. <
Steven.Miano at mybrighthouse.com> wrote:

> I've always just done:
>
> Me too!


> $ps aux | grep bash | grep -v grep
>
> Is there something wrong with that?
>

No, just more typing and one more process.


> On the error in the book that's interesting, I wasn't able to reproduce the
> same error using the same command successively....8.04/LTS/i386
>

Of course, you have to do something at the command line before running the
command. I'll show you later what is.


> ~Steven
>
> ________________________________________
> From: ubuntu-us-fl-bounces at lists.ubuntu.com [
> ubuntu-us-fl-bounces at lists.ubuntu.com] On Behalf Of j.e.aneiros [
> jesus.aneiros at gmail.com]
> Sent: Wednesday, September 15, 2010 9:39 AM
> To: Mailing list for Ubuntu Florida LoCo Team
> Subject: [ubuntu-florida] Avoid That grep Command in grep Output
>
> Hello everyone,
>
> I'm planning to send everyday at least a message to the list with something
> interesting about Linux. This is the first one.
>
> One week ago I bought the book "Official Ubuntu Server Book, The (2nd
> Edition)". Being a command line fan I went directly to the section "Cool
> tips and tricks". I started reading and I found out that the explanation of
> the first trick is in a certain way wrong.
>
> The idea behind the trick is to avoid the appearance of grep in resulting
> list for a command like:
>
> janeiros at harlie:~$ ps ax | grep bash
> 13235 tty1     S      0:00 -bash
> 13256 tty1     S+     0:00 /bin/bash /usr/bin/startx
> 16911 pts/0    Ss+    0:00 -bash
> 17005 pts/1    Ss     0:00 -bash
> 17152 pts/1    S+     0:00 grep --color=auto bash
>
> The authors suggest a "trick" running the command in this form:
>
> janeiros at harlie:~$ ps ax | grep [b]ash
>
>  How come when I try the trick is OK the first time and wrong at the second
> one?
>
> janeiros at harlie:~$ ps ax | grep [b]ash
> 13235 tty1     S      0:00 -bash
> 13256 tty1     S+     0:00 /bin/bash /usr/bin/startx
> 16911 pts/0    Ss+    0:00 -bash
> 17005 pts/1    Ss     0:00 -bash
>
> You can see grep is gone.
>
> And now is back:
>
> janeiros at harlie:~$ ps ax | grep [b]ash
> 13235 tty1     S      0:00 -bash
> 13256 tty1     S+     0:00 /bin/bash /usr/bin/startx
> 16911 pts/0    Ss+    0:00 -bash
> 17005 pts/1    Ss     0:00 -bash
> 17185 pts/1    S+     0:00 grep --color=auto bash
>
> Of course, I did something in between that provoked the change! What was
> it? Let see if somebody find out what was. The authors' explanation for the
> trick is not exact!
>
> The explanation is right there at the command line!
>
> If nobody finds out I'll tell you later today.
>
> By the way there is an alternative to the trick but it's longer.
>
> Have a good day!
>
> PS. The outputs of the commands weren't edited at all.
>
> --
> J. E. Aneiros
> GNU/Linux User #190716 en http://counter.li.org
> perl -e '$_=pack(c5,0105,0107,0123,0132,(1<<3)+2);y[A-Z][N-ZA-M];print;'
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-- 
J. E. Aneiros
GNU/Linux User #190716 en http://counter.li.org
perl -e '$_=pack(c5,0105,0107,0123,0132,(1<<3)+2);y[A-Z][N-ZA-M];print;'
PK fingerprint: 5179 917E 5B34 F073 E11A  AFB3 4CB3 5301 4A80 F674
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