Perl Regex - Print the matched value

Question

What is the perl regex to print the matched value? For eg I want to print 195 from this string

"2011-04-11 00:39:28,736::[main]::INFO (Main.java:73) Test.Main::main() Total Successful Transactions = 195". 

How can I do that? Thanks in advance

Answer 1

You can use parentheses in regex to capture substrings. The captured groups are stored in $1, $2, and so on. Example:

while (<>) {     if (/Total Successful Transactions = (\d+)/) {         print "$1\n";     } } 

or, somewhat shorter:

while (<>) {     print "$1\n" if /Total Successful Transactions = (\d+)/; } 

You can also make use of the fact that the match operator (//) in list context returns a list of what was matched by groups:

$\ = '\n'; # Output newline after each print. while (<>) {     print for /Total Successful Transactions = (\d+)/; } 

Which lets you write a compact one-liner (the -l option automatically adds newlines to each print, among other things):

perl -lne 'print for /Total Successful Transactions = (\d+)/'