Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -1560,10 +1560,11 @@
 	AC_SUBST(OF_PROCESS_M, "OFProcess.m")
 	AC_DEFINE(OF_HAVE_PROCESSES, 1, [Whether we have processes])
 ])
 
 AC_CHECK_HEADERS_ONCE([complex.h sys/ioctl.h sys/ttycom.h])
+AC_CHECK_FUNCS(isatty)
 
 AC_CHECK_FUNC(pledge, [
 	AC_DEFINE(OF_HAVE_PLEDGE, 1, [Whether we have pledge()])
 ])
 

Index: src/OFStdIOStream.h
==================================================================
--- src/OFStdIOStream.h
+++ src/OFStdIOStream.h
@@ -24,10 +24,12 @@
 
 OF_ASSUME_NONNULL_BEGIN
 
 /*! @file */
 
+@class OFColor;
+
 /*!
  * @class OFStdIOStream OFStdIOStream.h ObjFW/OFStdIOStream.h
  *
  * @brief A class for providing standard input, output and error as OFStream.
  *
@@ -62,10 +64,31 @@
  *	  number of rows could not be queried.
  */
 @property (readonly, nonatomic) int rows;
 
 - (instancetype)init OF_UNAVAILABLE;
+
+/*!
+ * @brief Sets the foreground color on the underlying terminal. Does nothing if
+ *	  there is no underlying terminal or colors are unsupported.
+ *
+ * @param color The foreground color to set
+ */
+- (void)setForegroundColor: (OFColor *)color;
+
+/*!
+ * @brief Sets the background color on the underlying terminal. Does nothing if
+ *	  there is no underlying terminal or colors are unsupported.
+ *
+ * @param color The background color to set
+ */
+- (void)setBackgroundColor: (OFColor *)color;
+
+/*!
+ * @brief Resets forward and background color.
+ */
+- (void)resetColor;
 @end
 
 #ifdef __cplusplus
 extern "C" {
 #endif

Index: src/OFStdIOStream.m
==================================================================
--- src/OFStdIOStream.m
+++ src/OFStdIOStream.m
@@ -28,10 +28,11 @@
 # include <sys/ttycom.h>
 #endif
 
 #import "OFStdIOStream.h"
 #import "OFStdIOStream+Private.h"
+#import "OFColor.h"
 #import "OFDate.h"
 #import "OFApplication.h"
 #ifdef OF_WINDOWS
 # include "OFWin32ConsoleStdIOStream.h"
 #endif
@@ -93,10 +94,51 @@
 	[of_stderr writeFormat: @"[%@.%03d %@(%d)] %@\n", dateString,
 				date.microsecond / 1000, me, getpid(), msg];
 
 	objc_autoreleasePoolPop(pool);
 }
+
+#ifdef HAVE_ISATTY
+static int
+colorToANSI(OFColor *color)
+{
+	if ([color isEqual: [OFColor black]])
+		return 30;
+	if ([color isEqual: [OFColor maroon]])
+		return 31;
+	if ([color isEqual: [OFColor green]])
+		return 32;
+	if ([color isEqual: [OFColor olive]])
+		return 33;
+	if ([color isEqual: [OFColor navy]])
+		return 34;
+	if ([color isEqual: [OFColor purple]])
+		return 35;
+	if ([color isEqual: [OFColor teal]])
+		return 36;
+	if ([color isEqual: [OFColor silver]])
+		return 37;
+	if ([color isEqual: [OFColor grey]])
+		return 90;
+	if ([color isEqual: [OFColor red]])
+		return 91;
+	if ([color isEqual: [OFColor lime]])
+		return 92;
+	if ([color isEqual: [OFColor yellow]])
+		return 93;
+	if ([color isEqual: [OFColor blue]])
+		return 94;
+	if ([color isEqual: [OFColor fuchsia]])
+		return 95;
+	if ([color isEqual: [OFColor aqua]])
+		return 96;
+	if ([color isEqual: [OFColor white]])
+		return 97;
+
+	return -1;
+}
+#endif
 
 @implementation OFStdIOStream
 #ifndef OF_WINDOWS
 + (void)load
 {
@@ -368,6 +410,46 @@
 	return ws.ws_row;
 #else
 	return -1;
 #endif
 }
+
+- (void)setForegroundColor: (OFColor *)color
+{
+#ifdef HAVE_ISATTY
+	int code;
+
+	if (!isatty(_fd))
+		return;
+
+	if ((code = colorToANSI(color)) == -1)
+		return;
+
+	[self writeFormat: @"\033[%um", code];
+#endif
+}
+
+- (void)setBackgroundColor: (OFColor *)color
+{
+#ifdef HAVE_ISATTY
+	int code;
+
+	if (!isatty(_fd))
+		return;
+
+	if ((code = colorToANSI(color)) == -1)
+		return;
+
+	[self writeFormat: @"\033[%um", code + 10];
+#endif
+}
+
+- (void)resetColor
+{
+#ifdef HAVE_ISATTY
+	if (!isatty(_fd))
+		return;
+
+	[self writeString: @"\033[0m"];
+#endif
+}
 @end