Re: OT: Linux Shell Script

Hi Tyson,

Try this:

dans_at_dans-desktop:~/tmp/tyson$ cat a.txt | sed -e '/3/{
N
/3\n4/d
}
'

HTH,
Dan #13685 (RS/Sec/SP)
Troubleshooting blog: http://dans-net.com

On Wed, Apr 28, 2010 at 7:19 AM, Tyson Scott <tscott_at_ipexpert.com> wrote:

> Hey guys,
>
>
>
> Ignore this if you are not familiar with Linux. I am throwing this out
> because I expected it to work and can't get it working.
>
>
>
> I am trying to create a bash script to delete two lines in a file only if
> they are directly connected to one another.
>
>
>
> For example if I had a file "file.txt" with the following lines
>
> 1
>
> 2
>
> 3
>
> 4
>
> 5
>
>
>
> And I wanted to delete the lines with 3 & 4 but only if they were together.
> i.e. I want to make sure I am not deleting if they are:
>
> 1
>
> 3
>
> 2
>
> 4
>
> 5
>
>
>
> I know I could do
>
> sed '/3/d' -i file.txt;sed '/4/d' -i file.txt
>
>
>
> but that doesn't make sure they are directly together
>
>
>
> I tried
>
>
>
> sed '/3$\r\n4/d' -i file.txt
>
>
>
> But it seems either it doesn't match or I am using the incorrect regular
> expression
>
>
>
> I know I could also do
>
>
>
> cat file.txt | grep -v 3 | grep -v 4 > file.txt
>
>
>
> but still not making sure it is one line. Any thoughts would be
> appreciated. I believe there should be a way to do this with sed but I
> wouldn't call myself a guru on the great intricacies of sed. If not then I
> will just use expect, but I wanted to keep it simplistic.
>
>
>
> I know with expect I can do
>
> expect -re "\n3\r\n4" { exec sed '/3/d' -i file.txt;sed '/4/d' -i file.txt
> }
>
>
>
> And that verifies the two lines are together and then I can delete the
> files
> based off of them being together but I was hoping to stick with a simple
> bash shell script for this task.
>
>
>
> Regards,
>
>
>
> Tyson Scott - CCIE #13513 R&S, Security, and SP
>
> Technical Instructor - IPexpert, Inc.
>
> Mailto: tscott_at_ipexpert.com
>
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Received on Wed Apr 28 2010 - 08:20:27 ART