help with perl


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting help with perl
# 1  
Old 05-16-2008
help with perl

Hi,

I have a set of files where one of the lines in each file will have a <cd> tag in it when i grep for it. It may be in two formats,

1. </ab><cd>35250</cd>
2. <cd>35250</cd>

However it may be, i need to get the number value between <cd>" "</cd>.

Hope i am clear on my question, I am writing a perl script, i have used substr and index commands, but did not work for me, if anyone has any suggestions i appreciate it.

Thanks--
# 2  
Old 05-16-2008
Code:
if (m%<cd>(.*?)</cd>%) { $stuff = $1 }

... provided the start and end tags are always on the same line. If there can be multiple occurrences on the same line, you need to add a loop and a /g flag, too.
# 3  
Old 05-16-2008
Bug

Quote:
Originally Posted by era
Code:
if (m%<cd>(.*?)</cd>%) { $stuff = $1 }

... provided the start and end tags are always on the same line. If there can be multiple occurrences on the same line, you need to add a loop and a /g flag, too.
Thanks era, yes they are always in the same line. Can you please explain me what exactly is it doing?
as far as my understanding goes - (.*?) this is fetching the all the values in between the tags .. what does the m% do? and is $1 output from the if condition?
if (m%<cd>(.*?)</cd>%) { $stuff = $1 }

thanks again for you quick replySmilie
# 4  
Old 05-16-2008
m%....% is a regular expression match; you'd normally see /.../ or m/.../ but we don't want to use slashes when the pattern itself contains slashes.

If there is a match, the part of the string which matched the parenthesized part of the regular expression will be in $1.
# 5  
Old 05-16-2008
Thanks for you reply era. THis is the code i am using to fetch the number value in between <cd>????</cd> .. but this is the case when this tag is in the same way in all files .. but when </ab><cd>????</cd> this is the case where this will not be able to handle ..
i am little confused about how to fit in ur code here .. can you help me on this .. i really appreciate it.. Thanks--

foreach my $file (@array_files){
open(fh,">>","tmp.out");
# if (m%<cd>(.*?)</cd>%) { $stuff = $1 }
print fh `tail $file|grep "^<cd>"|grep "</cd>"| cut -d"<" -f 2|cut -c 4-`;
close fh;
}
# 6  
Old 05-16-2008
What's the point of using Perl if the one thing Perl can do really well is handled by a shell function?

Code:
#!/usr/bin/perl -n
if (m%<cd>(.*?)</cd>% { print "$1\n" }

Save that to a file and run it from a shell script which invokes it on each file in turn. Or just type this one-liner directly at the prompt.

Code:
perl -ne 'if (m%<cd>(.*?)</cd>%) { print "$1\n" }' *.txt >tmp.out

# 7  
Old 05-16-2008
Thanks era, the one liner helps! Smilie
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Programming

PERL: In a perl-scripttTrying to execute another perl-script that SETS SOME VARIABLES !

I have reviewed many examples on-line about running another process (either PERL or shell command or a program), but do not find any usefull for my needs way. (Reviewed and not useful the system(), 'back ticks', exec() and open()) I would like to run another PERL-script from first one, not... (1 Reply)
Discussion started by: alex_5161
1 Replies

2. Programming

Perl: restrict perl from automaticaly creating a hash branches on check

My issue is that the perl script (as I have done it so far) created empty branches when I try to check some branches on existence. I am using multydimentional hashes: found it as the best way for information that I need to handle. Saing multidimentional I means hash of hashes ... So, I have ... (2 Replies)
Discussion started by: alex_5161
2 Replies

3. Shell Programming and Scripting

Perl :: reading values from Data Dumper reference in Perl

Hi all, I have written a perl code and stored the data into Data structure using Data::Dumper module. But not sure how to retreive the data from the Data::Dumper. Eg. Based on the key value( Here CRYPTO-6-IKMP_MODE_FAILURE I should be able to access the internal hash elements(keys) ... (1 Reply)
Discussion started by: scriptscript
1 Replies

4. UNIX for Advanced & Expert Users

perl and HP-UX : instmodsh in combination with software depot : update inventory for installed Perl

we create a HP-UX software depot with a new perl-modul. after installation of the software depot, the perl module i can't find with instmodsh in the inventory for installed Perl modules. - i have learned of using instmodsh command : i find out what modules are already installed on my system. ... (0 Replies)
Discussion started by: bora99
0 Replies

5. Shell Programming and Scripting

HELP on Perl array / sorting - trying to convert Korn Shell Script to Perl

Hi all, Not sure if this should be in the programming forum, but I believe it will get more response under the Shell Programming and Scripting FORUM. Am trying to write a customized df script in Perl and need some help with regards to using arrays and file handlers. At the moment am... (3 Replies)
Discussion started by: newbie_01
3 Replies

6. Shell Programming and Scripting

Hidden Characters in Regular Expression Matching Perl - Perl Newbie

I am completely new to perl programming. My father is helping me learn said programming language. However, I am stuck on one of the assignments he has given me, and I can't find very much help with it via google, either because I have a tiny attention span, or because I can be very very dense. ... (4 Replies)
Discussion started by: kittyluva2
4 Replies

7. Shell Programming and Scripting

Perl :How to print the o/p of a Perl script on console and redirecting same in log file @ same time.

How can i print the output of a perl script on a unix console and redirect the same in a log file under same directory simultaneously ? Like in Shell script, we use tee, is there anything in Perl or any other option ? (2 Replies)
Discussion started by: butterfly20
2 Replies

8. Shell Programming and Scripting

perl/unix: script in command line works but not in perl

so in unix this command works works and shows me a list of directories find . -name \*.xls -exec dirname {} \; | sort -u | > list.txt but when i try running a perl script to run this command my $query = 'find . -name \*.xls -exec dirname {} \; | sort -u | > list.txt';... (2 Replies)
Discussion started by: kpddong
2 Replies

9. Shell Programming and Scripting

Passing date formats in Perl: i.e. Jul/10/2007 -> 20070710 (yyyymmdd) - Perl

Hi , This script working for fine if pass script-name.sh Jul/10/2007 ,I want to pass 20070710(yyyymmdd) .Please any help it should be appereciated. use Time::Local; my $d = $ARGV; my $t = $ARGV; my $m = ""; @d = split /\//, $d; @t = split /:/, $t; if ( $d eq "Jan" ) { $m = 0 }... (7 Replies)
Discussion started by: akil
7 Replies

10. Shell Programming and Scripting

[Perl] Accessing array elements within a sed command in Perl script

I am trying to use a script to replace the header of each file, whose filename are stored within the array $test, using the sed command within a Perl script as follows: $count = 0; while ( $count < $#test ) { `sed -e 's/BIOGRF 321/BIOGRF 332/g' ${test} > 0`; `cat 0 >... (2 Replies)
Discussion started by: userix
2 Replies
Login or Register to Ask a Question