diff --git a/src/dirname.c b/src/dirname.c
index 56f0bda..11aaa66 100644
--- a/src/dirname.c
+++ b/src/dirname.c
@@ -19,6 +19,11 @@
 #include <libgen.h>
 #include <stdio.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"dirname"
+#endif
+
 
 /* dirname */
 static int _dirname(char * arg)
@@ -31,7 +36,7 @@ static int _dirname(char * arg)
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: dirname string\n", stderr);
+	fputs("Usage: " PROGNAME " string\n", stderr);
 	return 1;
 }
 
diff --git a/src/du.c b/src/du.c
index 3c5e886..1e76e9c 100644
--- a/src/du.c
+++ b/src/du.c
@@ -23,6 +23,11 @@
 #include <stdio.h>
 #include <string.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"du"
+#endif
+
 
 /* Prefs */
 typedef int Prefs;
@@ -51,7 +56,7 @@ static int _du(Prefs * prefs, int argc, char * argv[])
 
 static int _du_error(char const * error)
 {
-	fputs("du: ", stderr);
+	fputs(PROGNAME ": ", stderr);
 	perror(error);
 	return 1;
 }
@@ -183,7 +188,7 @@ static void _du_print(Prefs * prefs, off_t size, char const * filename)
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: du [-a | -s][-kx][-H | -L][file...]\n\
+	fputs("Usage: " PROGNAME " [-a | -s][-kx][-H | -L][file...]\n\
   -a	Report the size of every file encountered\n\
   -s	Report only the total sum for each of the specified files\n\
   -k	Write the file sizes in units of 1024 bytes rather than 512\n\
diff --git a/src/echo.c b/src/echo.c
index 7814f37..9671ce4 100644
--- a/src/echo.c
+++ b/src/echo.c
@@ -18,6 +18,11 @@
 #include <unistd.h>
 #include <stdio.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"echo"
+#endif
+
 
 /* echo */
 static int _echo(int argc, char * argv[])
@@ -38,7 +43,7 @@ static int _echo(int argc, char * argv[])
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: echo [string...]\n", stderr);
+	fputs("Usage: " PROGNAME " [string...]\n", stderr);
 	return 1;
 }
 
diff --git a/src/false.c b/src/false.c
index 0a27897..96a1a67 100644
--- a/src/false.c
+++ b/src/false.c
@@ -18,11 +18,16 @@
 #include <unistd.h>
 #include <stdio.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"false"
+#endif
+
 
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: false\n", stderr);
+	fputs("Usage: " PROGNAME "\n", stderr);
 	return 1;
 }
 
diff --git a/src/file.c b/src/file.c
index d169a31..9c0fb8c 100644
--- a/src/file.c
+++ b/src/file.c
@@ -20,6 +20,11 @@
 #include <unistd.h>
 #include <stdio.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"file"
+#endif
+
 
 /* prefs */
 typedef int Prefs;
@@ -83,8 +88,8 @@ static int _file_do(Prefs * p, char const * filename)
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: file [-dh][-M file][-m file] file ...\n\
-       file -i [-h] file ...\n", stderr);
+	fputs("Usage: " PROGNAME " [-dh][-M file][-m file] file ...\n\
+       " PROGNAME " -i [-h] file ...\n", stderr);
 	return 1;
 }
 
diff --git a/src/find.c b/src/find.c
index 7e46b7b..5b0623b 100644
--- a/src/find.c
+++ b/src/find.c
@@ -29,6 +29,11 @@
 #include <grp.h>
 #include <errno.h>
 
+/* constants */
+#ifndef PROGNAME
+# define PROGNAME	"find"
+#endif
+
 
 /* types */
 typedef int Prefs;
@@ -85,14 +90,14 @@ static int _find(Prefs * prefs, int argc, char * argv[])
 
 static int _find_error(char const * message, int ret)
 {
-	fputs("find: ", stderr);
+	fputs(PROGNAME ": ", stderr);
 	perror(message);
 	return ret;
 }
 
 static int _find_error_user(char const * message, char const * error, int ret)
 {
-	fprintf(stderr, "%s%s: %s\n", "find: ", message, error);
+	fprintf(stderr, "%s%s: %s\n", PROGNAME ": ", message, error);
 	return ret;
 }
 
@@ -308,7 +313,7 @@ static int _do_dir(Prefs * prefs, char const * pathname, int cmdc,
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: find [-H|-L] path... [expression...]\n"
+	fputs("Usage: " PROGNAME " [-H|-L] path... [expression...]\n"
 "  -H	De-reference links unless dangling or in the command line\n"
 "  -L	De-reference links always\n", stderr);
 	return 1;