#!/usr/bin/perl -w

my %lookup = ();

# Construct the lookup table
while (<INFO>) {
    chomp;
    my @list = split;   # assuming space separated
    $lookup{$list[0]} = $list[1];  # search => replace
}

# Go through the search file and check for lookup strings using
# the hash and replace it with the hash-value

while (<SRCHFILE>) {
    for my $k (keys %lookup) {
        s/$k/$lookup{$k}/g;
    }
    print;
}