How to use a regular expression on a text file

[weloki]

Greetings, this is a newbie question: I need to know how to tell perl to use a regular expression on a text file and print the results. If I have a file "talk.txt" and I want to match all the strings, "abc" in that file, how do I tell perl to use the regexp on talk.txt? How would I get the all of those matches to be displayed? Thanks in advance.

 

[PaulTEG]

Screw regex

grep is your answer

seek and find

--Paul

 

[mikevh]

while (<>) {
    print if /abc/;
}

 

[weloki]

Thank you for your responses.

PaulTEG, Ok, how do I invoke grep on a Windows machine?

mikevh, where would I place the name of the talk.txt file that I need to search in?

 

[zvrcvm]

like this:

open (FILE, &quot;<test.txt&quot;
while (<FILE>) {
print if /abc/;
}
close FILE;

This will print all the text lines in test.txt that contain &quot;abc&quot;

D.

Masochist: Windows programmer with a smile.

 

[PaulTEG]

grep is part of the POSIX toolset for windows, there is also a grep built on Borland's Turbo Pascal

Google'll find it

--Paul

 

[mikevh]

Cygwin also has it, along with lots of other useful stuff.

http://www.cygwin.com/

 

[ishnid]

From the command line:

perl -ne "print if /abc/" test.txt

This will print all the text lines in test.txt that contain &quot;abc&quot; (equivalent to typing &quot;grep abc test.txt&quot

 

[PaulTEG]

grep &quot;abc&quot; test.txt
vs
perl -ne &quot;print if /abc/&quot; test.txt

grep is 15 keystrokes more economical
;P

 

[ishnid]

&quot;grep is 15 keystrokes more economical&quot;

Indeed, so that leaves you with 15 keystrokes to play with getting grep to work on a Win32 machine!

 

[MikeLacey]

15 keystrokes to get grep working... ambitious...

Mike

Want to get great answers to your Tek-Tips questions? Have a look at faq219-2884

It's like this; even samurai have teddy bears, and even teddy bears get drunk.

 

[icrf]

If inside a script, you could try File::Grep [1].

Otherwise, you can try 'ppm install prep' and see if it can grep &quot;perl grep&quot; [2] off cpan (gets in close to your 15 characters ), else you'll need 'perl -MCPAN -e &quot;install prep&quot;' which loses your immidiate advantage. Repeat usage might bring an advantage, but I guess that's not the point, is it?

[1]

http://search.cpan.org/~mneylon/File-Grep-0.01/Grep.pm

[2]

http://search.cpan.org/~awrigley/prep-1.03/prep

________________________________________
Andrew - Perl Monkey

 

[weloki]

I want to express my gratitude for all of your replies, it really helped. It appears there are many ways to do one task. I now have a great head start on my projects, thanks to you all. 2thumbsup