Cuting/executing text from a file

Feynman · 08-25-2010, 09:39 AM

I need a way to read and delete text found before a unique string, then delete the string. I would like to have the text stored in a variable--or better yet--executed it as a shell script directly.

I intend to execute the stored text in bash. It does not matter much what language the program is it, however efficiency is desirable. This script is not going to be used on large files, but it may be executed many times sequentially so the faster the script works the better.

Thanks

Here is an example:

exclamation-"It worked!"
echo $exclamation
cd
end of script
blah blah
blah blah blah
blah blah blah

I would like to execute everything before "end of script" as if it were a shell script

Sergei Steshenko · 08-25-2010, 09:42 AM

Quote:

Originally Posted by Feynman

I need a way to read and delete text found before a unique string, then delete the string. I would like to have the text stored in a variable--or better yet--executed it as a shell script directly.

I intend to execute the stored text in bash. It does not matter much what language the program is it, however efficiency is desirable. This script is not going to be used on large files, but it may be executed many times sequentially so the faster the script works the better.

Thanks

Here is an example:

exclamation-"It worked!"
echo $exclamation
cd
end of script

blah blah blah
blah blah blah

http://www.linuxquestions.org/questi...ml#post4076233

; this is yet another indication that input data is poorly organized - the piece to be executed should have been in a separate file in the first place.

Sergei Steshenko · 08-25-2010, 09:48 AM

Also:

perldoc perlopentut
perldoc -f open
perldoc -f chmod
perldoc -f system
.

Feynman · 08-25-2010, 09:59 AM

This is actually not part of data extracting. See, the other part of the program is to make input files. I have a method where I make a template that is very similar to the input file for the actual program, except certain numbers replaced with parameters. I have the script fill in parameters (e.g. $1, $2 ...) and create the input file.
However, different programs have different syntax for execution. I would like to have both the template for the input and the script to execute it and parse the output all in one file--for easy use. So if I made the script to execute the input and parse the output the first part of the file, then separate it by some string that is not a command for any widely used language. Then I just have the template part of the file follow.

I cannot help that the output of quantum chemistry packages is poorly organized. My task is to graph the potential energy of water as a function of bond length. I have some good tools that can get me pretty far, and I am not about to rewrite Hartree-Fock algorithms when I can parse text.

ghostdog74 · 08-25-2010, 10:13 AM

Quote:

Originally Posted by Feynman

I need a way to read and delete text found before a unique string, then delete the string. I would like to have the text stored in a variable--or better yet--executed it as a shell script directly.

seriously, give a better example next time. Show what your desired output is.

Code:

$ more file
blah blah junk
blah blah myunique string
this is the end

$ awk '/myunique/{gsub(/.*myunique/,"");f=1}f' file
 string
this is the end

Feynman · 08-25-2010, 10:31 AM

Sorry, I was trying to execute everything before "end of script"--I edited the question. I am sorry for the confusion.

Feynman · 08-25-2010, 10:51 AM

Sergei Steshenko-- I tried

#!/bin/perl
while (<$ARGV[0]>) {
eval if $1 .. /$ARGV[1]/
}

can you help me fix this?

Sergei Steshenko · 08-25-2010, 10:58 AM

Quote:

Originally Posted by Feynman

Sergei Steshenko-- I tried

#!/bin/perl
while (<$ARGV[0]>) {
eval if $1 .. /$ARGV[1]/
}

can you help me fix this?

Why 'eval' ? I.e. are you going to extract Perl code ?

Reread my post #3 in the thread ( http://www.linuxquestions.org/questi...0/#post4077249 ) - it suggests the functions to be used and their order.

Also, dealing with Perl first and foremost put in the beginning of your script, just after the '#!/bin/perl',

Code:

use strict;
use warnings;

and make sure the script compiles and issues no runtime warnings.