10 files changed, 10 insertions, 0 deletions
diff --git a/src/aardig.c b/src/aardig.c
index 5772054..0388782 100644
--- a/src/aardig.c
+++ b/src/aardig.c
@@ -41,6 +41,7 @@ static char** parse_options(int argc, char **argv, int *niceness) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "aardig: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/hoofd.c b/src/hoofd.c
index 62d1151..9e428e9 100644
--- a/src/hoofd.c
+++ b/src/hoofd.c
@@ -44,6 +44,7 @@ static char** parse_options(int argc, char **argv, int *n, int *c) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "hoofd: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/ja.c b/src/ja.c
index 6b37b02..3d6135d 100644
--- a/src/ja.c
+++ b/src/ja.c
@@ -30,6 +30,7 @@ static char** parse_options(int argc, char **argv) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "ja: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/kat.c b/src/kat.c
index 5549b24..0a17ddc 100644
--- a/src/kat.c
+++ b/src/kat.c
@@ -30,6 +30,7 @@ static char** parse_options(int argc, char **argv) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "kat: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/omd.c b/src/omd.c
index 2291a6c..71b8dee 100644
--- a/src/omd.c
+++ b/src/omd.c
@@ -29,6 +29,7 @@ static char** parse_options(int argc, char **argv) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "omd: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/spons.c b/src/spons.c
index f59bd25..51bb109 100644
--- a/src/spons.c
+++ b/src/spons.c
@@ -36,6 +36,7 @@ static char** parse_options(int argc, char **argv, bool *a) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "spons: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/tak.c b/src/tak.c
index cbe5a3b..245a85c 100644
--- a/src/tak.c
+++ b/src/tak.c
@@ -31,6 +31,7 @@ static char** parse_options(int argc, char **argv) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "tak: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/toilet.c b/src/toilet.c
index ce42aca..aa4fbfa 100644
--- a/src/toilet.c
+++ b/src/toilet.c
@@ -58,6 +58,7 @@ static char** parse_options(int argc, char **argv, int *modeMap) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "toilet: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/weerklank.c b/src/weerklank.c
index 477aef4..ad03389 100644
--- a/src/weerklank.c
+++ b/src/weerklank.c
@@ -45,6 +45,7 @@ static char** parse_options(int argc, char **argv, struct options *opts) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "weerklank: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }
diff --git a/src/wiebenik.c b/src/wiebenik.c
index 71b321d..5d71ef4 100644
--- a/src/wiebenik.c
+++ b/src/wiebenik.c
@@ -31,6 +31,7 @@ static char** parse_options(int argc, char **argv) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "wiebenik: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }