Question

The file looks like

[N the computer end] [M whatever] [N you look] [N why not]

I only need the words in the bracket that start with [N
so here I want to get the computer end you look why not
they may or may not in the same line

I tried something like this:

if($line =~/\[N(.+?)\]/)

but it only match the first one of each line.

Answer 1

Use the g modifier on the regular expression to look for “g”lobal matches. Either like this:

while ($line =~ /\[N(.+?)\]/g) {
    # $1 contains the text between "[N" and "]"
}

Or like this:

my @matches = $line =~ /\[N(.+?)\]/g;
# @matches contains all of the matching items of text