How can I parse this text file to get the first group of digits on each line?

Question

I got a text file of this kind

INFO [main] (porter.java:100) - Added record 7147  read from file: 1484301                 
INFO [main] (porter.java:100) - Added record 7148  read from file: 1484302   
INFO [main] (porter.java:100) - Added record 17147 read from file: 1484303  
INFO [main] (porter.java:100) - Added record 76148 read from file: 1484333  
INFO [main] (porter.java:100) - Added record 148   read from file: 1484342

How can I parse this, getting the first digits in this case like

7147
7148
17147
76148
148

Answer 1

A regex would work nicely. Depending on what else is in the file you could get away with

while (<>) {
    next unless my ($n) = /Added record ([0-9]+)/;
    print "$n\n";
} 

Answer 2

I was thinking of the following pattern for the regex:

my ($n) = /record ([0-9]+)/;

This might capture lines containing Deleted record | Appended record | Changed record | etc. etc..

Answer 3

From the shell:

perl -wlane'print $F[6]' <infile >outfile

or

cut -d ' ' -f 7 <infile >outfile