diff --git a/src/utils.cpp b/src/utils.cpp
index 8ff37ca..576cebd 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -7,18 +7,23 @@
 
 using namespace sc;
 
-term::term() {
-    if (isatty(STDOUT_FILENO)) {
-        throw_if_min1(ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws));
+term::term(int fd) {
+    if (isatty(fd)) {
+        throw_if_min1(ioctl(fd, TIOCGWINSZ, &_ws));
+    }
+    switch (fd) {
+        case STDOUT_FILENO: _out = &std::cout; break;
+        case STDERR_FILENO: _out = &std::cerr; break;
+        default: break;
     }
 }
 
 int term::rows() const {
-    return ws.ws_row;
+    return _ws.ws_row;
 }
 
 int term::cols() const {
-    return ws.ws_col;
+    return _ws.ws_col;
 }
 
 void term::progress(double cur, double total) const {
@@ -31,27 +36,27 @@ void term::progress(double cur, double total) const {
     int maxsteps = barwidth * 8;
     int steps = round(cur * maxsteps / total);
     int perc = round(100 * cur / total);
-    std::cerr << '\r' << std::setw(3) << perc << "% ";
+    *_out << '\r' << std::setw(3) << perc << "% ";
     for (int i = 0; i < steps / 8; ++i) {
-        std::cerr << bar[7];
+        *_out << bar[7];
     }
     if (steps % 8) {
-        std::cerr << bar[steps % 8 - 1];
+        *_out << bar[steps % 8 - 1];
     }
 }
 
 void term::hide_cursor() const {
-    std::cerr << "\x1b[?25l";
+    *_out << "\x1b[?25l";
 }
 
 void term::show_cursor() const {
-    std::cerr << "\x1b[?25h";
+    *_out << "\x1b[?25h";
 }
 
-cursor_hider::cursor_hider() {
-    t.hide_cursor();
+cursor_hider::cursor_hider(int fd) : _t {fd} {
+    _t.hide_cursor();
 }
 
 cursor_hider::~cursor_hider() {
-    t.show_cursor();
+    _t.show_cursor();
 }
diff --git a/src/utils.hpp b/src/utils.hpp
index f4c8853..c17b4f4 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -4,14 +4,16 @@
 #include <unistd.h>
 #include <termios.h>
 #include <sys/ioctl.h>
+#include <iostream>
 
 namespace sc {
 
     class term {
-        struct winsize ws;
+        struct winsize _ws;
+        std::ostream* _out {nullptr};
 
         public:
-            term();
+            term(int fd);
 
             int rows() const;
             int cols() const;
@@ -23,10 +25,10 @@ namespace sc {
     };
 
     class cursor_hider {
-        term t;
+        term _t;
 
         public:
-            cursor_hider();
+            cursor_hider(int fd);
             ~cursor_hider();
     };