[Cialug] Grep Block of Text

[Daniel A. Ramaley]

For this type of problem i would usually use perl and change the line
delimiter. For example:

perl -e '$/="}\n"; while (<>) { print if /home.*dalef/ }' < example.conf

On 11/14/19 7:19 AM, Todd Walton wrote:
> More often than I'd expect, I find myself wanting to grep for a certain
> pattern in a certain file, and have it return the entire block of text that
> the pattern was in. I wish I had a single command that took three inputs, a
> pattern defining the start of the block, a pattern to find, and a pattern
> defining the end of the block of text. For example,
> 
> [todd ~]$ cat example.conf
> class users::people {
>     @username { 'chris':
>         comment     => 'Chris Manz',
>         home        => '/home/chris',
>         uid         => '1010',
>         pgroup      => '400',
>         groups      => ['it','admins'],
>         password    => '$1$3PbnUhBE6hPVP4E10',
>         shell       => '/bin/bash',
>         ensure      => 'absent',
>         expiry      => '2019-01-01'
>     }
>     @username { 'kellid':
>         comment     => 'Kelli Deacon',
>         home        => '/home/kellid',
>         uid         => '1051',
>         pgroup      => '400',
>         groups      => ['it','admins'],
>         password    => '$6$KBpSaACi14vny/xeE1',
>         shell       => '/bin/bash',
>         ensure      => 'absent',
>         expiry      => '2019-01-01'
>     }
>     @username { 'dalef':
>         comment     => 'Dale Fitzgerald',
>         home        => '/home/dalef',
>         uid         => '1023',
>         pgroup      => '400',
>         groups      => ['it','admins'],
>         password    => '$1$jfFSl.A15w.0m1gb/1',
>         shell       => '/bin/bash',
>         ensure      => 'absent',
>         expiry      => '2016-09-07'
>     }
> 
> [todd ~]$ grep-block --pcre --begin '^\s+ at username' --pattern
> '^.*home.*dalef..$' --end '^\s+\}' example.conf
>     @username { 'dalef':
>         comment     => 'Dale Fitzgerald',
>         home        => '/home/dalef',
>         uid         => '1023',
>         pgroup      => '400',
>         groups      => ['it','admins'],
>         password    => '$1$jfFSl.A15w.0m1gb/1',
>         shell       => '/bin/bash',
>         ensure      => 'absent',
>         expiry      => '2016-09-07'
>     }
> 
> [todd ~]$ apropos suggestions?
> suggestions?: nothing appropriate.
> 
> Though the awk answer doesn't seem to work, here's one StackOverflow
> question:
> https://stackoverflow.com/questions/19926634
> 
> Here's some good suggestions for a slightly different scenario (matching on
> the delimiters, not on the innards):
> https://unix.stackexchange.com/questions/122313/how-to-grep-blocks-or-i-should-use-awk-ack
> 
> And also, gee golly, it sure would be nice to use Perl-compatible regular
> expressions instead of POSIX. I know I can use awk with RS set to something
> other than newline, but I want a more general solution, and... PCREs.
> 
> --
> Todd
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__
Daniel Ramaley | Server Engineer 2
Information Technology Services | Drake University
T: +1-515-271-4540
W: http://www.drake.edu/its