And here's the Path::Tiny version...

#!/usr/bin/perl

# https://perlmonks.org/?node_id=1222734

use strict;
use warnings;
use Path::Tiny;

my $lookuptxtfile = 'd.lookuptxtfile';
path($lookuptxtfile)->spew(<<END);
one
two
The action failed.
three
The action failed.  twice The action failed.
four
END
print path($lookuptxtfile)->slurp;
print "\n";

# end setup for testing

# start actual code

path($lookuptxtfile)->edit( sub { s/The action failed./failed_build/g 
+} );

# end actual code

print path($lookuptxtfile)->slurp; # debug print
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