diff --git a/src/engine/execunix.c b/src/engine/execunix.c
index 1ef15a34e..9709d89cb 100644
--- a/src/engine/execunix.c
+++ b/src/engine/execunix.c
@@ -66,7 +66,7 @@
  */
 
 static clock_t tps = 0;
-static struct timeval tv;
+static struct timespec tv;
 static int select_timeout = 0;
 static int intr = 0;
 static int cmdsrunning = 0;
@@ -91,6 +91,7 @@ static struct
     void    (*func)( void *closure, int status, timing_info*, const char *, const char * );
     void   *closure;
     time_t  start_dt;         /* start of command timestamp */
+    long    msgsize[2];
 } cmdtab[ MAXJOBS ] = {{0}};
 
 /*
@@ -342,28 +343,36 @@ void exec_cmd
 
 int read_descriptor( int i, int s )
 {
-    int  ret;
-    int  len;
+    int  ret = 1, len, err;
     char buffer[BUFSIZ];
 
-    while ( 0 < ( ret = fread( buffer, sizeof(char),  BUFSIZ-1, cmdtab[ i ].stream[ s ] ) ) )
-    {
-        buffer[ret] = 0;
-        if  ( !cmdtab[ i ].buffer[ s ] )
-        {
-            /* Never been allocated. */
-            cmdtab[ i ].buffer[ s ] = (char*)BJAM_MALLOC_ATOMIC( ret + 1 );
-            memcpy( cmdtab[ i ].buffer[ s ], buffer, ret + 1 );
-        }
-        else
-        {
-            /* Previously allocated. */
-            char * tmp = cmdtab[ i ].buffer[ s ];
-            len = strlen( tmp );
-            cmdtab[ i ].buffer[ s ] = (char*)BJAM_MALLOC_ATOMIC( len + ret + 1 );
-            memcpy( cmdtab[ i ].buffer[ s ], tmp, len );
-            memcpy( cmdtab[ i ].buffer[ s ] + len, buffer, ret + 1 );
-            BJAM_FREE( tmp );
+    while ( 0 < ( ret = fread( buffer, sizeof(char),  BUFSIZ-1, cmdtab[ i ].stream[ s ] ) ) ) {
+
+        /* only copy action data until hit buffer limit, then ignore rest of data */
+        if (cmdtab[i].msgsize[s] < globs.maxbuf) {
+            cmdtab[i].msgsize[s] += ret;
+            buffer[ret] = 0;
+            if  ( !cmdtab[ i ].buffer[ s ] )
+            {
+                /* Never been allocated. */
+                cmdtab[ i ].buffer[ s ] = (char*)BJAM_MALLOC_ATOMIC( ret + 1 );
+                memcpy( cmdtab[ i ].buffer[ s ], buffer, ret + 1 );
+            }
+            else
+            {
+                /* Previously allocated. */
+                char * tmp = cmdtab[ i ].buffer[ s ];
+                len = strlen( tmp );
+                cmdtab[ i ].buffer[ s ] = (char*)BJAM_MALLOC_ATOMIC( len + ret + 1 );
+                memcpy( cmdtab[ i ].buffer[ s ], tmp, len );
+                memcpy( cmdtab[ i ].buffer[ s ] + len, buffer, ret + 1 );
+                BJAM_FREE( tmp );
+            }
+
+            /* buffer was truncated, append newline to ensure pjl can find line end */
+            if (globs.maxbuf <= cmdtab[i].msgsize[s]) {
+                cmdtab[i].buffer[s][cmdtab[i].msgsize[s]-1] = '\n';
+            }
         }
     }
 
@@ -379,6 +388,8 @@ void close_streams( int i, int s )
 
     close(cmdtab[ i ].fd[ s ]);
     cmdtab[ i ].fd[ s ] = 0;
+
+    cmdtab[i].msgsize[s] = 0;
 }
 
 
@@ -423,6 +434,61 @@ void populate_file_descriptors( int * fmax, fd_set * fds)
     *fmax = fd_max;
 }
 
+void cleanup_child(int i, int status) 
+{
+    int         rstat;
+    struct tms  new_time;
+    timing_info time_info;
+
+    cmdtab[ i ].pid = 0;
+
+    /* Set reason for exit if not timed out. */
+    if ( WIFEXITED( status ) ) {
+        cmdtab[ i ].exit_reason = 0 == WEXITSTATUS( status )
+            ? EXIT_OK : EXIT_FAIL;
+    }
+
+    /* Print out the rule and target name. */
+    out_action( cmdtab[ i ].action, cmdtab[ i ].target,
+        cmdtab[ i ].command, cmdtab[ i ].buffer[ OUT ],
+        cmdtab[ i ].buffer[ ERR ], cmdtab[ i ].exit_reason
+    );
+
+    times( &new_time );
+
+    time_info.system = (double)( new_time.tms_cstime - old_time.tms_cstime ) / CLOCKS_PER_SEC;
+    time_info.user   = (double)( new_time.tms_cutime - old_time.tms_cutime ) / CLOCKS_PER_SEC;
+    time_info.start  = cmdtab[ i ].start_dt;
+    time_info.end    = time( 0 );
+
+    old_time = new_time;
+
+    if ( intr )
+        rstat = EXEC_CMD_INTR;
+    else if ( status != 0 )
+        rstat = EXEC_CMD_FAIL;
+    else
+        rstat = EXEC_CMD_OK;
+
+    /* Assume -p0 in effect so only pass buffer[ 0 ]
+     * containing merged output.
+     */
+     (*cmdtab[ i ].func)( cmdtab[ i ].closure, rstat, &time_info, cmdtab[ i ].command, cmdtab[ i ].buffer[ 0 ] );
+
+     BJAM_FREE( cmdtab[ i ].buffer[ OUT ] );
+     cmdtab[ i ].buffer[ OUT ] = 0;
+
+     BJAM_FREE( cmdtab[ i ].buffer[ ERR ] );
+     cmdtab[ i ].buffer[ ERR ] = 0;
+
+     BJAM_FREE( cmdtab[ i ].command );
+     cmdtab[ i ].command = 0;
+
+     cmdtab[ i ].func = 0;
+     cmdtab[ i ].closure = 0;
+     cmdtab[ i ].start_time = 0;
+}
+
 
 /*
  * exec_wait() - wait and drive at most one execution completion.
@@ -430,16 +496,13 @@ void populate_file_descriptors( int * fmax, fd_set * fds)
 
 int exec_wait()
 {
-    int         i;
+    int         i, j;
     int         ret;
     int         fd_max;
     int         pid;
     int         status;
     int         finished;
-    int         rstat;
-    timing_info time_info;
     fd_set      fds;
-    struct tms  new_time;
 
     /* Handle naive make1() which does not know if commands are running. */
     if ( !cmdsrunning )
@@ -457,17 +520,47 @@ int exec_wait()
             /* Force select() to timeout so we can terminate expired processes.
              */
             tv.tv_sec = select_timeout;
-            tv.tv_usec = 0;
+            tv.tv_nsec = 0;
 
             /* select() will wait until: i/o on a descriptor, a signal, or we
              * time out.
              */
-            ret = select( fd_max + 1, &fds, 0, 0, &tv );
+            ret = pselect( fd_max + 1, &fds, 0, 0, &tv, &empty_sigmask );
         }
         else
         {
-            /* select() will wait until i/o on a descriptor or a signal. */
-            ret = select( fd_max + 1, &fds, 0, 0, 0 );
+            /* pselect() will wait until i/o on a descriptor or a signal. */
+            ret = pselect( fd_max + 1, &fds, 0, 0, 0, &empty_sigmask );
+        }
+
+        if (-1 == ret && errno != EINTR) {
+            perror("pselect()");
+            exit(-1);
+        }
+
+        if (0 < child_events) {
+            /* child terminated via SIGCHLD */
+            for (i=0; i<MAXJOBS; ++i) {
+                if (0 < terminated_children[i].pid) {
+                    pid_t pid = terminated_children[i].pid;
+                    /* get index of terminated pid */
+                    for (j=0; j<globs.jobs; ++j) {
+                        if (pid == cmdtab[j].pid) {
+                            /* cleanup loose ends for terminated process */
+                            close_streams(j, OUT);
+                            if ( globs.pipe_action != 0 ) close_streams(j, ERR);
+                            cleanup_child(j, terminated_children[i].status);
+                            --cmdsrunning;
+                            finished = 1;
+                            break;
+                        }
+                    }
+                    /* clear entry from list */
+                    terminated_children[i].status = 0;
+                    terminated_children[i].pid = 0;
+                    --child_events;
+                }
+            }
         }
 
         if ( 0 < ret )
@@ -496,62 +589,10 @@ int exec_wait()
 
                     if ( pid == cmdtab[ i ].pid )
                     {
+                        /* move into function so signal handler can also use */
                         finished = 1;
-                        pid = 0;
-                        cmdtab[ i ].pid = 0;
-
-                        /* Set reason for exit if not timed out. */
-                        if ( WIFEXITED( status ) )
-                        {
-                            cmdtab[ i ].exit_reason = 0 == WEXITSTATUS( status )
-                                ? EXIT_OK
-                                : EXIT_FAIL;
-                        }
-
-                        /* Print out the rule and target name. */
-                        out_action( cmdtab[ i ].action, cmdtab[ i ].target,
-                            cmdtab[ i ].command, cmdtab[ i ].buffer[ OUT ],
-                            cmdtab[ i ].buffer[ ERR ], cmdtab[ i ].exit_reason
-                        );
-
-                        times( &new_time );
-
-                        time_info.system = (double)( new_time.tms_cstime - old_time.tms_cstime ) / CLOCKS_PER_SEC;
-                        time_info.user   = (double)( new_time.tms_cutime - old_time.tms_cutime ) / CLOCKS_PER_SEC;
-                        time_info.start  = cmdtab[ i ].start_dt;
-                        time_info.end    = time( 0 );
-
-                        old_time = new_time;
-
-                        /* Drive the completion. */
+                        cleanup_child(i, status);
                         --cmdsrunning;
-
-                        if ( intr )
-                            rstat = EXEC_CMD_INTR;
-                        else if ( status != 0 )
-                            rstat = EXEC_CMD_FAIL;
-                        else
-                            rstat = EXEC_CMD_OK;
-
-                        /* Assume -p0 in effect so only pass buffer[ 0 ]
-                         * containing merged output.
-                         */
-                        (*cmdtab[ i ].func)( cmdtab[ i ].closure, rstat,
-                            &time_info, cmdtab[ i ].command,
-                            cmdtab[ i ].buffer[ 0 ] );
-
-                        BJAM_FREE( cmdtab[ i ].buffer[ OUT ] );
-                        cmdtab[ i ].buffer[ OUT ] = 0;
-
-                        BJAM_FREE( cmdtab[ i ].buffer[ ERR ] );
-                        cmdtab[ i ].buffer[ ERR ] = 0;
-
-                        BJAM_FREE( cmdtab[ i ].command );
-                        cmdtab[ i ].command = 0;
-
-                        cmdtab[ i ].func = 0;
-                        cmdtab[ i ].closure = 0;
-                        cmdtab[ i ].start_time = 0;
                     }
                     else
                     {
@@ -562,7 +603,6 @@ int exec_wait()
             }
         }
     }
-
     return 1;
 }
 
diff --git a/src/engine/jam.c b/src/engine/jam.c
index db4964845..d997b7b77 100644
--- a/src/engine/jam.c
+++ b/src/engine/jam.c
@@ -102,6 +102,8 @@
  */
 
 
+#include "limits.h"
+
 #include "jam.h"
 #include "option.h"
 #include "patchlevel.h"
@@ -134,9 +136,36 @@
 #endif
 
 /* And UNIX for this. */
-#ifdef unix
+#if defined(unix) || defined(__unix)
     #include <sys/utsname.h>
+    #include <sys/wait.h>
     #include <signal.h>
+
+     #include <sys/utsname.h>
+     #include <signal.h>
+
+     sigset_t empty_sigmask;
+     volatile sig_atomic_t child_events = 0;
+     struct terminated_child terminated_children[MAXJOBS] = {{ 0 }};
+
+     void child_sig_handler(int x) {
+         pid_t pid;
+         int i, status;
+         pid = waitpid(-1, &status, WNOHANG);
+         if (0 < pid) {
+           /* save terminated child pid and status */
+           for (i=0; i<MAXJOBS; ++i) {
+             /* find first available slot */
+             if (terminated_children[i].pid == 0) {
+                 terminated_children[i].pid = pid;
+                 terminated_children[i].status = status;
+                 break;
+             }
+           }
+         }
+         ++child_events;
+         signal(SIGCHLD, child_sig_handler);
+     }
 #endif
 
 struct globs globs =
@@ -152,7 +181,9 @@ struct globs globs =
     { 0, 1 },   /* debug ... */
 #endif
     0,          /* output commands, not run them */
-    0           /* action timeout */
+    0,          /* action timeout */
+    0,          
+    INT_MAX     /* default is to accept all action output */
 };
 
 /* Symbols to be defined as true for use in Jambase. */
@@ -230,6 +261,19 @@ int main( int argc, char * * argv, char * * arg_environ )
     char            const * progname = argv[0];
     module_t              * environ_module;
 
+#if defined(unix) || defined(__unix)
+    sigset_t sigmask;
+    struct sigaction sa;
+
+    sigemptyset(&sigmask);
+    sigaddset(&sigmask, SIGCHLD);
+    sigprocmask(SIG_BLOCK, &sigmask, NULL);
+    sa.sa_flags = 0;
+    sa.sa_handler = child_sig_handler;
+    sigaction(SIGCHLD, &sa, NULL);
+    sigemptyset(&empty_sigmask);
+#endif
+
     saved_argv0 = argv[0];
 
     BJAM_MEM_INIT();
@@ -241,7 +285,7 @@ int main( int argc, char * * argv, char * * arg_environ )
     --argc;
     ++argv;
 
-    if ( getoptions( argc, argv, "-:l:d:j:p:f:gs:t:ano:qv", optv ) < 0 )
+    if ( getoptions( argc, argv, "-:l:m:d:j:p:f:gs:t:ano:qv", optv ) < 0 )
     {
         printf( "\nusage: %s [ options ] targets...\n\n", progname );
 
@@ -251,6 +295,7 @@ int main( int argc, char * * argv, char * * arg_environ )
         /* printf( "-g      Build from newest sources first.\n" ); */
         printf( "-jx     Run up to x shell commands concurrently.\n" );
         printf( "-lx     Limit actions to x number of seconds after which they are stopped.\n" );
+        printf( "-mx     Limit action output buffer to x kb's of data, after which action output is read and ignored.\n" );
         printf( "-n      Don't actually execute the updating actions.\n" );
         printf( "-ox     Write the updating actions to file x.\n" );
         printf( "-px     x=0, pipes action stdout and stderr merged into action output.\n" );
@@ -318,6 +363,9 @@ int main( int argc, char * * argv, char * * arg_environ )
     if ( ( s = getoptval( optv, 'l', 0 ) ) )
         globs.timeout = atoi( s );
 
+    if ( ( s = getoptval( optv, 'm', 0 ) ) )
+        globs.maxbuf = atoi( s ) * 1024;
+
     /* Turn on/off debugging */
     for ( n = 0; ( s = getoptval( optv, 'd', n ) ); ++n )
     {
@@ -396,7 +444,7 @@ int main( int argc, char * * argv, char * * arg_environ )
                    VAR_SET );
 
         /* Set JAMUNAME. */
-#ifdef unix
+#if defined(unix) || defined(__unix)
         {
             struct utsname u;
 
diff --git a/src/engine/jam.h b/src/engine/jam.h
index 26b94a7f7..d3d9a0b06 100644
--- a/src/engine/jam.h
+++ b/src/engine/jam.h
@@ -456,10 +456,20 @@ struct globs
                                  * default 0 for no limit.
                                  */
     int    dart;                /* output build and test results formatted for Dart */
+    int    maxbuf;              /* limit action output buffer to maxbuf kb's of data */
 };
 
 extern struct globs globs;
 
+struct terminated_child
+{
+    pid_t  pid;
+    int    status;
+};
+
+extern struct terminated_child terminated_children[MAXJOBS];
+
+
 #define DEBUG_MAKE     ( globs.debug[ 1 ] )   /* show actions when executed */
 #define DEBUG_MAKEQ    ( globs.debug[ 2 ] )   /* show even quiet actions */
 #define DEBUG_EXEC     ( globs.debug[ 2 ] )   /* show text of actons */
@@ -493,4 +503,12 @@ extern struct globs globs;
 /* They also get the profile functions. */
 #include "debug.h"
 
+/* Handle child process termination */
+#if defined(unix) || defined(__unix)
+#include <signal.h>
+extern sigset_t empty_sigmask;
+extern volatile sig_atomic_t child_events;
+void child_sig_handler(int x);
+#endif
+
 #endif