diff --git a/bin/pt-mext b/bin/pt-mext
index 0e522065..af0f6b4b 100755
--- a/bin/pt-mext
+++ b/bin/pt-mext
@@ -599,9 +599,9 @@ for i in `_seq $NUM`; do
    NEXTFILE=$(($i + 1))
 
    # Sort each file and eliminate empty lines, so 'join' doesn't complain.
-   sort "$FILE$i" | grep . > "$FILE$i.tmp"
+   sort -s "$FILE$i" | grep . > "$FILE$i.tmp"
    mv "$FILE$i.tmp" "$FILE$i"
-   sort "$FILE${NEXTFILE}" | grep . > "$FILE${NEXTFILE}.tmp"
+   sort -s "$FILE${NEXTFILE}" | grep . > "$FILE${NEXTFILE}.tmp"
    mv "$FILE${NEXTFILE}.tmp" "$FILE${NEXTFILE}"
 
    # Join the files together.  This gets slow O(n^2) as we add more files, but
@@ -610,7 +610,7 @@ for i in `_seq $NUM`; do
 
    # Find the max length of the [numeric only] values in the file so we know how
    # wide to make the columns
-   MAXLEN=`awk '{print $2}' "$FILE${NEXTFILE}" | grep -v '[^0-9]' | awk '{print length($1)}' | sort -rn | head -n1`
+   MAXLEN=`awk '{print $2}' "$FILE${NEXTFILE}" | grep -v '[^0-9]' | awk '{print length($1)}' | sort -rns | head -n1`
    mv "$FILE" "$FILE${NEXTFILE}"
    SPEC="$SPEC %${MAXLEN}d";
 
diff --git a/t/pt-online-schema-change/pt-1455.t b/t/pt-online-schema-change/pt-1455.t
index 1af031fd..78d86389 100644
--- a/t/pt-online-schema-change/pt-1455.t
+++ b/t/pt-online-schema-change/pt-1455.t
@@ -53,7 +53,7 @@ my $num_rows = 1000;
 my $master_port = 12345;
 
 diag("Loading $num_rows into the table. This might take some time.");
-diag(`util/mysql_random_data_load --host=127.1 --port=$master_port --user=msandbox --password=msandbox employees t1 $num_rows`);
+diag(`util/mysql_random_data_load --host=127.0.0.1 --port=$master_port --user=msandbox --password=msandbox employees t1 $num_rows`);
 diag("$num_rows rows loaded. Starting tests.");
 
 $master_dbh->do("FLUSH TABLES");
diff --git a/t/pt-online-schema-change/pt-229.t b/t/pt-online-schema-change/pt-229.t
index d91d1fdf..2b8ed8c3 100644
--- a/t/pt-online-schema-change/pt-229.t
+++ b/t/pt-online-schema-change/pt-229.t
@@ -46,7 +46,7 @@ $sb->load_file('master', "t/pt-online-schema-change/samples/pt-229.sql");
 
 my $num_rows = 40000;
 diag("Loading $num_rows into the table. This might take some time.");
-diag(`util/mysql_random_data_load --host=127.1 --port=12345 --user=msandbox --password=msandbox test test_a $num_rows`);
+diag(`util/mysql_random_data_load --host=127.0.0.1 --port=12345 --user=msandbox --password=msandbox test test_a $num_rows`);
 diag("$num_rows rows loaded. Starting tests.");
 $master_dbh->do("FLUSH TABLES");
 
diff --git a/t/pt-online-schema-change/pt-244.t b/t/pt-online-schema-change/pt-244.t
index f0c4dd50..f3e351a1 100644
--- a/t/pt-online-schema-change/pt-244.t
+++ b/t/pt-online-schema-change/pt-244.t
@@ -53,7 +53,7 @@ $sb->load_file('master3', "t/pt-online-schema-change/samples/pt-244.sql");
 
 my $num_rows = 1000;
 diag("Loading $num_rows into the table. This might take some time.");
-diag(`util/mysql_random_data_load --host=127.1 --port=$master3_port --user=msandbox --password=msandbox test t3 $num_rows`);
+diag(`util/mysql_random_data_load --host=127.0.0.1 --port=$master3_port --user=msandbox --password=msandbox test t3 $num_rows`);
 diag("$num_rows rows loaded. Starting tests.");
 
 $dbh3->do("FLUSH TABLES");
diff --git a/t/pt-online-schema-change/slave_lag.t b/t/pt-online-schema-change/slave_lag.t
index 58c13f70..c57d7a44 100644
--- a/t/pt-online-schema-change/slave_lag.t
+++ b/t/pt-online-schema-change/slave_lag.t
@@ -32,7 +32,7 @@ my $dp = new DSNParser(opts=>$dsn_opts);
 my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
 my $master_dbh = $sb->get_dbh_for('master');
 my $slave_dbh = $sb->get_dbh_for('slave1');
-my $master_dsn = 'h=127.1,P=12345,u=msandbox,p=msandbox';
+my $master_dsn = 'h=127.0.0.1,P=12345,u=msandbox,p=msandbox';
 
 if ( !$master_dbh ) {
    plan skip_all => 'Cannot connect to sandbox master';
@@ -65,7 +65,7 @@ $sb->load_file('master', "t/pt-online-schema-change/samples/slave_lag.sql");
 
 my $num_rows = 10000;
 diag("Loading $num_rows into the table. This might take some time.");
-diag(`util/mysql_random_data_load --host=127.1 --port=12345 --user=msandbox --password=msandbox test pt178 $num_rows`);
+diag(`util/mysql_random_data_load --host=127.0.0.1 --port=12345 --user=msandbox --password=msandbox test pt178 $num_rows`);
 
 # Run a full table scan query to ensure the slave is behind the master
 # There is no query cache in MySQL 8.0+
@@ -89,7 +89,7 @@ like(
 
 # Repeat the test now using --check-slave-lag
 $args = "$master_dsn,D=test,t=pt178 --execute --chunk-size 1 --max-lag 5 --alter 'ENGINE=InnoDB' "
-      . "--check-slave-lag h=127.1,P=12346,u=msandbox,p=msandbox,D=test,t=sbtest";
+      . "--check-slave-lag h=127.0.0.1,P=12346,u=msandbox,p=msandbox,D=test,t=sbtest";
 
 # Run a full table scan query to ensure the slave is behind the master
 reset_query_cache($master_dbh, $master_dbh);