diff --git a/20231012/cat-01.txt b/20231012/cat-01.txt
new file mode 100644
index 0000000000000000000000000000000000000000..db0a17e98db801810d0e7b30ab4b046a3e56ed79
--- /dev/null
+++ b/20231012/cat-01.txt
@@ -0,0 +1,20 @@
+cassini/home/peter/bo/2023ws/dbs/20231012> cat > privet.c
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Привет, мир!\n");
+  return 0;
+}
+cassini/home/peter/bo/2023ws/dbs/20231012> cat privet.c
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Привет, мир!\n");
+  return 0;
+}
+cassini/home/peter/bo/2023ws/dbs/20231012> gcc -Wall -O privet.c -o privet
+cassini/home/peter/bo/2023ws/dbs/20231012> ./privet
+Привет, мир!
+cassini/home/peter/bo/2023ws/dbs/20231012>
diff --git a/20231012/chmod-01.txt b/20231012/chmod-01.txt
new file mode 100644
index 0000000000000000000000000000000000000000..0acf454fa0efc8a63042f8ee8f005ea03caf0449
--- /dev/null
+++ b/20231012/chmod-01.txt
@@ -0,0 +1,13 @@
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod -r hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+--w------- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> cat hello.c
+cat: hello.c: Keine Berechtigung
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod +r hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rw-r--r-- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod -r hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod u+r hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rw------- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012>
diff --git a/20231012/chmod-02.txt b/20231012/chmod-02.txt
new file mode 100644
index 0000000000000000000000000000000000000000..ca9cf1547e8d88985ebdaad290f7fc7ea78a757a
--- /dev/null
+++ b/20231012/chmod-02.txt
@@ -0,0 +1,15 @@
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod 640 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rw-r----- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod 750 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rwxr-x--- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> bc
+bc 1.07.1
+Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006, 2008, 2012-2017 Free Software Foundation, Inc.
+This is free software with ABSOLUTELY NO WARRANTY.
+For details type `warranty'.
+obase=13
+ibase=13
+6 * 9
+42
diff --git a/20231012/chmod-03.txt b/20231012/chmod-03.txt
new file mode 100644
index 0000000000000000000000000000000000000000..903c2a0d6c4359d07a3482e8475d78e4ac2995d0
--- /dev/null
+++ b/20231012/chmod-03.txt
@@ -0,0 +1,12 @@
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rwxr-x--- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod uo+w g-x u-r hello.c
+chmod: Zugriff auf 'g-x' nicht möglich: Datei oder Verzeichnis nicht gefunden
+chmod: Zugriff auf 'u-r' nicht möglich: Datei oder Verzeichnis nicht gefunden
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod uo+w  hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod g-x  hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod u-r  hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+--wxr---w- 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> chmod 775 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012>
diff --git a/20231012/chmod-04.txt b/20231012/chmod-04.txt
new file mode 100644
index 0000000000000000000000000000000000000000..8a0364d6e465ec4359fc2d07ace5dba64b10c510
--- /dev/null
+++ b/20231012/chmod-04.txt
@@ -0,0 +1,15 @@
+cassini/home/peter/bo/2023ws/dbs/20231012> ls -l hello.c
+-rwxrwxr-x 1 peter peter 82 12. Okt 12:20 hello.c
+cassini/home/peter/bo/2023ws/dbs/20231012> cat hello.c
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Hello, world!\n");
+  return 0;
+}
+cassini/home/peter/bo/2023ws/dbs/20231012> ./hello.c
+./hello.c: Zeile 3: Syntaxfehler beim unerwarteten Symbol »(«
+./hello.c: Zeile 3: `int main (void)'
+cassini/home/peter/bo/2023ws/dbs/20231012> # Dies ist ein Kommentar. ;-)
+cassini/home/peter/bo/2023ws/dbs/20231012>
diff --git a/20231012/dbs-20231012.pdf b/20231012/dbs-20231012.pdf
index af5921fe635732e43ddbf24792b1fc13ab179f50..35189610f9e23f5b18b599d2d51f592c0eef50b5 100644
Binary files a/20231012/dbs-20231012.pdf and b/20231012/dbs-20231012.pdf differ
diff --git a/20231012/dbs-20231012.tex b/20231012/dbs-20231012.tex
index 3c83e6c6c08738ea85e5b48be78739416725d117..418fc515517c108340d21900905d52d2145a567e 100644
--- a/20231012/dbs-20231012.tex
+++ b/20231012/dbs-20231012.tex
@@ -939,6 +939,8 @@
 
 \end{frame}
 
+\iffalse
+
 \begin{frame}[fragile]
 
   \showsubsection
@@ -1271,6 +1273,8 @@
 
 \end{frame}
 
+\fi
+
 \nosectionnonumber{\inserttitle}
 
 \begin{frame}
@@ -1290,7 +1294,9 @@
         \item[2.1] Grundkonzepte
         \color{medgreen}
         \item[2.2] Die Kommandozeile: Grundlagen
+        \color{orange}
         \item[2.3] Dateisysteme
+        \color{red}
         \item[2.4] Ein- und Ausgabeströme
         \item[2.5] Pipes
         \item[2.6] Verzweigungen und Schleifen
diff --git a/20231012/hello.c b/20231012/hello.c
old mode 100644
new mode 100755
diff --git a/20231012/privet.c b/20231012/privet.c
new file mode 100644
index 0000000000000000000000000000000000000000..b8ae3aee74e4648249ed0621babc11118c056600
--- /dev/null
+++ b/20231012/privet.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Привет, мир!\n");
+  return 0;
+}
diff --git a/20231012/pryvit.c b/20231012/pryvit.c
new file mode 100644
index 0000000000000000000000000000000000000000..d554df83ee6e29ddcce8d0fec53cf2b524a5df93
--- /dev/null
+++ b/20231012/pryvit.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Привiт, свiте!\n");
+  return 0;
+}
diff --git a/20231012/test/hello-world.c b/20231012/test/hello-world.c
new file mode 100644
index 0000000000000000000000000000000000000000..b19d80e9bd0bd7c5ed8f54b20c6a50d9166f03ac
--- /dev/null
+++ b/20231012/test/hello-world.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Hello, world!\n");
+  return 0;
+}