diff --git a/.gitignore b/.gitignore
index 3a3ea6e..3be968b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,5 @@ configure
 libtool
 stamp-*
 *-stamp
+src/zzuf
+test/zzcat
diff --git a/configure.ac b/configure.ac
index 4e9e47b..405c96c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,7 +29,7 @@ AC_SUBST(DLL_LDFLAGS)
 AC_CHECK_HEADERS(windows.h winsock2.h io.h process.h unistd.h inttypes.h stdint.h getopt.h libc.h malloc.h dlfcn.h regex.h sys/socket.h netinet/in.h sys/uio.h aio.h sys/mman.h sys/wait.h sys/resource.h sys/time.h endian.h)
 
 AC_CHECK_FUNCS(setenv waitpid setrlimit gettimeofday fork kill pipe _pipe)
-AC_CHECK_FUNCS(open64 lseek64 mmap64 fopen64 fseeko _IO_getc getline getdelim __getdelim fgetln __srefill map_fd memalign posix_memalign aio_read accept bind connect socket readv pread recv recvfrom recvmsg mmap valloc sigaction getpagesize)
+AC_CHECK_FUNCS(open64 lseek64 mmap64 fopen64 dup dup2 fseeko _IO_getc getline getdelim __getdelim fgetln __srefill map_fd memalign posix_memalign aio_read accept bind connect socket readv pread recv recvfrom recvmsg mmap valloc sigaction getpagesize)
 
 AC_CHECK_TYPES(sighandler_t, [], [],
   [#define _GNU_SOURCE
diff --git a/doc/zzuf.1 b/doc/zzuf.1
index c3a4fda..4fc574a 100644
--- a/doc/zzuf.1
+++ b/doc/zzuf.1
@@ -409,9 +409,10 @@ allocations, \fBzzuf\fR diverts and reimplements the following functions,
 which can be private libc symbols, too:
 .TP
 Unix file descriptor handling:
-\fBopen\fR(), \fBlseek\fR(), \fBread\fR(), \fBreadv\fR(), \fBpread\fR(),
-\fBaccept\fR(), \fBsocket\fR(), \fBrecv\fR(), \fBrecvfrom\fR(), \fBrecvmsg\fR(),
-\fBaio_read\fR(), \fBaio_return\fR(), \fBclose\fR()
+\fBopen\fR(), \fBdup\fR(), \fBdup2\fR(), \fBlseek\fR(), \fBread\fR(),
+\fBreadv\fR(), \fBpread\fR(), \fBaccept\fR(), \fBsocket\fR(), \fBrecv\fR(),
+\fBrecvfrom\fR(), \fBrecvmsg\fR(), \fBaio_read\fR(), \fBaio_return\fR(),
+\fBclose\fR()
 .TP
 Standard IO streams:
 \fBfopen\fR(), \fBfreopen\fR(), \fBfseek\fR(), \fBfseeko\fR(), \fBrewind\fR(),
diff --git a/src/lib-fd.c b/src/lib-fd.c
index 7230620..2ef9329 100644
--- a/src/lib-fd.c
+++ b/src/lib-fd.c
@@ -81,6 +81,12 @@ static int     (*ORIG(open))    (const char *file, int oflag, ...);
 #if defined HAVE_OPEN64
 static int     (*ORIG(open64))  (const char *file, int oflag, ...);
 #endif
+#if defined HAVE_DUP
+static int     (*ORIG(dup))     (int oldfd);
+#endif
+#if defined HAVE_DUP2
+static int     (*ORIG(dup2))    (int oldfd, int newfd);
+#endif
 #if defined HAVE_ACCEPT
 static int     (*ORIG(accept))  (int sockfd, struct sockaddr *addr,
                                  SOCKLEN_T *addrlen);
@@ -171,6 +177,53 @@ int NEW(open64)(const char *file, int oflag, ...)
 }
 #endif
 
+#if defined HAVE_DUP
+int NEW(dup)(int oldfd)
+{
+    int ret;
+
+    LOADSYM(dup);
+    ret = ORIG(dup)(oldfd);
+    if(!_zz_ready || _zz_islocked(-1) || !_zz_iswatched(oldfd)
+         || !_zz_isactive(oldfd))
+        return ret;
+
+    if(ret >= 0)
+    {
+        debug("%s(%i) = %i", __func__, oldfd, ret);
+        _zz_register(ret);
+    }
+
+    return ret;
+}
+#endif
+
+#if defined HAVE_DUP2
+int NEW(dup2)(int oldfd, int newfd)
+{
+    int ret;
+
+    LOADSYM(dup2);
+    ret = ORIG(dup2)(oldfd, newfd);
+    if(!_zz_ready || _zz_islocked(-1) || !_zz_iswatched(oldfd)
+         || !_zz_isactive(oldfd))
+        return ret;
+
+    if(ret >= 0)
+    {
+        /* We must close newfd if it was open, but only if oldfd != newfd
+         * and if dup2() suceeded. */
+        if(oldfd != newfd && _zz_iswatched(newfd) && _zz_isactive(newfd))
+            _zz_unregister(newfd);
+
+        debug("%s(%i, %i) = %i", __func__, oldfd, newfd, ret);
+        _zz_register(ret);
+    }
+
+    return ret;
+}
+#endif
+
 #if defined HAVE_ACCEPT
 int NEW(accept)(int sockfd, struct sockaddr *addr, SOCKLEN_T *addrlen)
 {