Split string into separate words, and then test to see if each word is the one we're looking for.
#!/usr/bin/perl
use warnings;
use strict;
my $found = 0;
$_ = "string... 'i'";
my $sought = "people";
foreach my $word (split) { if ($word eq $sought) {
$found = 1;
last;
}
} if ($found) {
print "Hooray! Found the word 'people'\n";
}