diff --git a/ivtest/perl-lib/Environment.pm b/ivtest/perl-lib/Environment.pm
index 492637193..ecdb49e15 100644
--- a/ivtest/perl-lib/Environment.pm
+++ b/ivtest/perl-lib/Environment.pm
@@ -11,7 +11,7 @@ our $VERSION = '1.03';
 
 use base 'Exporter';
 
-our @EXPORT = qw(get_args get_regress_fn get_ivl_version);
+our @EXPORT = qw(get_args get_regress_fn get_ivl_version run_program);
 
 use constant DEF_REGRESS_FN => './regress.list';  # Default regression list.
 use constant DEF_SUFFIX => '';  # Default suffix.
@@ -102,4 +102,26 @@ sub get_ivl_version {
     }
 }
 
+#
+# Run a subprogram. This avoids spawing an intermediate shell when output
+# is redirected to a log file.
+#
+sub run_program {
+    my ($cmd, $log_mode, $log_file) = @_;
+
+    my $pid = fork();
+    if (!defined($pid)) {
+        die("couldn't spawn new process\n");
+    } elsif ($pid == 0) {
+        if ($log_mode) {
+            open(STDOUT, $log_mode, $log_file) or die("couldn't open log file '$log_file'\n");
+            open(STDERR, '>&STDOUT');
+        }
+        exec($cmd);
+    } else {
+        waitpid($pid, 0);
+        $?; # return the child's exit status
+    }
+}
+
 1;  # Module loaded OK
diff --git a/ivtest/vlog95_reg.pl b/ivtest/vlog95_reg.pl
index d9021a7a9..25caee834 100755
--- a/ivtest/vlog95_reg.pl
+++ b/ivtest/vlog95_reg.pl
@@ -4,7 +4,7 @@
 #
 # This script is based on code with the following Copyright.
 #
-# Copyright (c) 1999-2024 Guy Hutchison (ghutchis@pacbell.net)
+# Copyright (c) 1999-2025 Guy Hutchison (ghutchis@pacbell.net)
 #
 #    This source code is free software; you can redistribute it
 #    and/or modify it in source code form under the terms of the GNU
@@ -126,9 +126,9 @@ sub execute_regression {
         $cmd .= $testtype{$tname} eq "CN" ? " -t null" : " -t vlog95";
         $cmd .= " -pfileline=1 -pspacing=4" if ($testtype{$tname} ne "CN");
         $cmd .= " -D__ICARUS_UNSIZED__ $args{$tname}";
-        $cmd .= " ./$srcpath{$tname}/$tname.v > log/$tname.log 2>&1";
+        $cmd .= " ./$srcpath{$tname}/$tname.v";
 #        print "$cmd\n";
-        if (system("$cmd")) {
+        if (run_program($cmd, '>', "log/$tname.log")) {
             if ($testtype{$tname} eq "CE") {
                 # Check if the system command core dumped!
                 if ($? >> 8 & 128) {
@@ -186,9 +186,9 @@ sub execute_regression {
         $args{$tname} =~ s/-gverilog-ams//g;
         $cmd = "iverilog$sfx -o vsim $gen_flag $args{$tname}";
         $cmd .= " -s $testmod{$tname}" if ($testmod{$tname} ne "");
-        $cmd .= " vlog95.v >> log/$tname.log 2>&1";
+        $cmd .= " vlog95.v";
 #        print "$cmd\n";
-        if ($pass_type == 0 and system("$cmd")) {
+        if ($pass_type == 0 and run_program($cmd, '>>', "log/$tname.log")) {
             if ($testtype{$tname} eq "TE") {
                 # Check if the system command core dumped!
                 if ($? >> 8 & 128) {
@@ -205,9 +205,9 @@ sub execute_regression {
             }
         }
 
-        $cmd = "vvp$sfx vsim $plargs{$tname} >> log/$tname.log 2>&1";
+        $cmd = "vvp$sfx vsim $plargs{$tname}";
 #        print "$cmd\n";
-        if ($pass_type == 0 and system("$cmd")) {
+        if ($pass_type == 0 and run_program($cmd, '>>', "log/$tname.log")) {
             if ($testtype{$tname} eq "RE") {
                 # Check if the system command core dumped!
                 if ($? >> 8 & 128) {
@@ -275,7 +275,7 @@ sub execute_regression {
 
     } continue {
         if ($tname ne "") {
-            system("rm -f ./vlog95.v ./vsim") and
+            run_program("rm -f ./vlog95.v ./vsim") and
                 die "Error: failed to remove temporary file.\n";
         }
     }
diff --git a/ivtest/vpi_reg.pl b/ivtest/vpi_reg.pl
index 03a192261..511b8dfb4 100755
--- a/ivtest/vpi_reg.pl
+++ b/ivtest/vpi_reg.pl
@@ -189,17 +189,16 @@ sub execute_regression {
         }
 
         $cmd = "iverilog-vpi$sfx --name=$tname $cargs{$tname} " .
-               "vpi/$ccode{$tname} > vpi_log/$tname.log 2>&1";
-        if (system("$cmd")) {
+               "vpi/$ccode{$tname}";
+        if (run_program($cmd, '>', "vpi_log/$tname.log")) {
             print "==> Failed - running iverilog-vpi.\n";
             $failed++;
             next;
         }
 
         $cmd = $with_valg ? "valgrind --trace-children=yes " : "";
-        $cmd .= "iverilog$sfx $args{$tname} -L . -m $tname -o vsim vpi/$tname.v >> " .
-                "vpi_log/$tname.log 2>&1";
-        if (system("$cmd")) {
+        $cmd .= "iverilog$sfx $args{$tname} -L . -m $tname -o vsim vpi/$tname.v";
+        if (run_program($cmd, '>>', "vpi_log/$tname.log")) {
             print "==> Failed - running iverilog.\n";
             $failed++;
             next;
@@ -207,8 +206,8 @@ sub execute_regression {
 
         $cmd = $with_valg ? "valgrind --leak-check=full " .
                             "--show-reachable=yes " : "";
-        $cmd .= "vvp$sfx vsim >> vpi_log/$tname.log 2>&1";
-        if (system("$cmd")) {
+        $cmd .= "vvp$sfx vsim";
+        if (run_program($cmd, '>>', "vpi_log/$tname.log")) {
             print "==> Failed - running vvp.\n";
             $failed++;
             next;
@@ -230,7 +229,7 @@ sub execute_regression {
         if ($tname ne "" and $ccode{$tname} ne "") {
             my $doto = $ccode{$tname};
             $doto =~ s/\.(c|cc|cpp)$/.o/;
-            system("rm -f $doto $tname.vpi vsim") and
+            run_program("rm -f $doto $tname.vpi vsim") and
                 die "Error: failed to remove temporary files.\n";
         }
     }
diff --git a/ivtest/vvp_reg.pl b/ivtest/vvp_reg.pl
index 4dc2853ca..77bdc93ed 100755
--- a/ivtest/vvp_reg.pl
+++ b/ivtest/vvp_reg.pl
@@ -4,7 +4,7 @@
 #
 # This script is based on code with the following Copyright.
 #
-# Copyright (c) 1999-2024 Guy Hutchison (ghutchis@pacbell.net)
+# Copyright (c) 1999-2025 Guy Hutchison (ghutchis@pacbell.net)
 #
 #    This source code is free software; you can redistribute it
 #    and/or modify it in source code form under the terms of the GNU
@@ -136,9 +136,9 @@ sub execute_regression {
         $cmd .= "iverilog$sfx -o vsim $ivl_args $args{$tname}";
         $cmd .= " -s $testmod{$tname}" if ($testmod{$tname} ne "");
         $cmd .= " -t null" if ($testtype{$tname} eq "CN");
-        $cmd .= " ./$srcpath{$tname}/$tname.v > log/$tname.log 2>&1";
+        $cmd .= " ./$srcpath{$tname}/$tname.v";
 #        print "$cmd\n";
-        if (system("$cmd")) {
+        if (run_program($cmd, '>', "log/$tname.log")) {
             if ($testtype{$tname} eq "CE") {
                 # Check if the system command core dumped!
                 if ($? >> 8 & 128) {
@@ -174,9 +174,9 @@ sub execute_regression {
 
         $cmd = $with_valg ? "valgrind --leak-check=full " .
                             "--show-reachable=yes " : "";
-        $cmd .= "vvp$sfx vsim $vvp_args $plargs{$tname} >> log/$tname.log 2>&1";
+        $cmd .= "vvp$sfx vsim $vvp_args $plargs{$tname}";
 #        print "$cmd\n";
-        if ($pass_type == 0 and system("$cmd")) {
+        if ($pass_type == 0 and run_program($cmd, '>>', "log/$tname.log")) {
             if ($testtype{$tname} eq "RE") {
                 # Check if the system command core dumped!
                 if ($? >> 8 & 128) {
@@ -242,7 +242,7 @@ sub execute_regression {
 
     } continue {
         if ($tname ne "") {
-            system("rm -f ./vsim && rm -rf ivl_vhdl_work") and
+            run_program("rm -rf ./vsim ivl_vhdl_work") and
                 die "Error: failed to remove temporary file.\n";
         }
     }
@@ -252,7 +252,7 @@ sub execute_regression {
                " Not Implemented=$not_impl, Expected Fail=$expected_fail\n");
 
     # Remove remaining temporary files
-    system("rm -f *.tmp ivltests/*.tmp");
+    run_program("rm -f *.tmp ivltests/*.tmp");
 
     return $failed;
 }