Re: [SLUG] Extracting string from a file - shell script

[Peter Chubb]

> "grove" == grove   writes:

grove> On Fri, 3 Jul 2009, Peter Chubb wrote:
>> Why use cat?
>> 
>> Why not > 
>> The extra process plus pipe just wastes resources.

grove> You've been reading too much Randal Schwartz.. ;)

grove> http://sial.org/howto/shell/useless-cat/

No I've never read that. But I come from a background running 60 users
on a pdp11-70 with 256k of core memory --- anything that used
unnecessary processes or memory was evil.
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Re: [SLUG] Extracting string from a file - shell script

[grove]

On Fri, 3 Jul 2009, Peter Chubb wrote:


Why use cat?

Why not 

You've been reading too much Randal Schwartz.. ;)

http://sial.org/howto/shell/useless-cat/


rachel

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Re: [SLUG] Extracting string from a file - shell script

[Kyle]

Thanks all.

Multiple options.  Will give them a go.



Kind Regards

Kyle


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Re: [SLUG] Extracting string from a file - shell script

[James Polley]

On Fri, Jul 3, 2009 at 9:08 AM, Kyle  wrote:

> Hi Folks,
>
> I am trying to extract a substring from a string found in a file.
>
> The string is: *** End   of  TF0220  at  Thu Jul 2 10:06:51 EST 2009  - RC
> =  0
>
> and the substring I want to extract is TF0220. This is a program name and
> the length of this name varies. In other words I want to extract whatever is
> between the words "of" and "at" in a script.


If the name is always at the same position in the string(ie, the line always
starts with "*** End   of " - "awk '{ print $4 ;}'" will do most of what you
want.

saga:~/src polleyj$ echo '*** End   of  TF0220  at  Thu Jul 2 10:06:51 EST
2009  - RC =  0' | awk '{ print $4 ;}'
TF0220

You probably want to do something extra to select out only lines matching
this pattern - you can do this by stipulating a match to awk - ie, make it
"awk '/End  of/ { print $4; }'"




>
> How would I likely go about that please?
>
> --
> 
> Kind Regards
>
> Kyle
>
> --
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> Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
>
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Re: [SLUG] Extracting string from a file - shell script

[Phil Scarratt]

Peter Chubb wrote:
>> "Phil" == Phil Scarratt  writes:
> Phil> Something like this would work:
> 
> Phil> cat  | perl -nle
> Phil> 'if(/^\*\*\*\s+End\s+of\s+([\S]+)\s+at\s+.*/){print $1;}'
> 
> 
> Why use cat?
> 
> Why not  
> The extra process plus pipe just wastes resources.
> 

Good point! But then again sed is probably a better option anyway

Fil
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Re: [SLUG] Extracting string from a file - shell script

[Peter Chubb]

> "Phil" == Phil Scarratt  writes:

Phil> Kyle wrote:
>> Hi Folks,
>> 
>> I am trying to extract a substring from a string found in a file.
>> 
>> The string is: *** End of TF0220 at Thu Jul 2 10:06:51 EST 2009 -
>> RC = 0
>> 
>> and the substring I want to extract is TF0220. This is a program
>> name and the length of this name varies. In other words I want to
>> extract whatever is between the words "of" and "at" in a script.
>> 
>> How would I likely go about that please?
>> 

Phil> Something like this would work:

Phil> cat  | perl -nle
Phil> 'if(/^\*\*\*\s+End\s+of\s+([\S]+)\s+at\s+.*/){print $1;}'


Why use cat?

Why not http://www.gelato.unsw.edu.au  peterc AT gelato.unsw.edu.au
http://www.ertos.nicta.com.au   ERTOS within National ICT Australia
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Re: [SLUG] Extracting string from a file - shell script

[Phil Scarratt]

Kyle wrote:
> Hi Folks,
> 
> I am trying to extract a substring from a string found in a file.
> 
> The string is: *** End   of  TF0220  at  Thu Jul 2 10:06:51 EST 2009  -
> RC =  0
> 
> and the substring I want to extract is TF0220. This is a program name
> and the length of this name varies. In other words I want to extract
> whatever is between the words "of" and "at" in a script.
> 
> How would I likely go about that please?
> 

Something like this would work:

cat  | perl -nle
'if(/^\*\*\*\s+End\s+of\s+([\S]+)\s+at\s+.*/){print $1;}'

Fil
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Re: [SLUG] Extracting string from a file - shell script

[Peter Chubb]

> "Kyle" == Kyle   writes:

Kyle> Hi Folks,

Kyle> I am trying to extract a substring from a string found in a
Kyle> file.

Kyle> The string is: *** End of TF0220 at Thu Jul 2 10:06:51 EST 2009
Kyle> - RC = 0

Simplest way is sed.

sed -n -e 's/^.*End of \([^ ]*\) at .*$/\1/p' filename

The regular expression matches an entire line, and throws away
everything but the bit you want.  I'm assuming that the bit you want
doesn't contain spaces, if it does, you need a different regular
expression. 

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Re: [SLUG] Extracting string from a file - shell script

[Dean Hamstead]

in perl, depending on how strictly you want to enforce the format of the 
TF0220 (in this case, just any string between 'End of' and 'at'.


#!/usr/bin/perl
use warnings;
use strict;
my $string = q|*** End   of  TF0220  at  Thu Jul 2 10:06:51 EST 2009  - 
 RC =  0|;

my ($var) = $string =~ /End\s+of\s+([\w\d]+)\s+at/;
print $var if $var;


Dean

Kyle wrote:

Hi Folks,

I am trying to extract a substring from a string found in a file.

The string is: *** End   of  TF0220  at  Thu Jul 2 10:06:51 EST 2009  - 
RC =  0


and the substring I want to extract is TF0220. This is a program name 
and the length of this name varies. In other words I want to extract 
whatever is between the words "of" and "at" in a script.


How would I likely go about that please?



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[SLUG] Extracting string from a file - shell script

[Kyle]

Hi Folks,

I am trying to extract a substring from a string found in a file.

The string is: *** End   of  TF0220  at  Thu Jul 2 10:06:51 EST 2009  - 
RC =  0


and the substring I want to extract is TF0220. This is a program name 
and the length of this name varies. In other words I want to extract 
whatever is between the words "of" and "at" in a script.


How would I likely go about that please?

--

Kind Regards

Kyle

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