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Lerntagebuch/Woche_12.md

+# 📖 Lerntagebuch - Woche 12
+
+---
+
+### **Thema: Paketmanagement mit apt und apt-get**
+
+#### **Vorbereitungen**
+- **Hilfefunktion genutzt**: `apt --help`
+- Interessante Befehle:
+  - `apt list --upgradable` → zeigt alle aktualisierbaren Pakete an.
+  - `apt show <paketname>` → zeigt detaillierte Informationen zu einem Paket.
+
+#### **Systemaktualisierung**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $sudo apt update
+Get:1 https://deb.parrot.sh/parrot lory InRelease [29.8 kB]
+Get:2 https://deb.parrot.sh/direct/parrot lory-security InRelease [29.4 kB]
+Get:3 https://deb.parrot.sh/parrot lory-backports InRelease [29.7 kB]
+Get:4 https://deb.parrot.sh/parrot lory/main amd64 Packages [19.2 MB]
+Get:5 https://deb.parrot.sh/direct/parrot lory-security/main amd64 Packages [476 kB]
+Get:6 https://deb.parrot.sh/parrot lory-backports/main amd64 Packages [658 kB]
+Get:7 https://deb.parrot.sh/parrot lory-backports/contrib amd64 Packages [10.9 kB]
+Fetched 20.4 MB in 6s (3596 kB/s)                           
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+20 packages can be upgraded. Run 'apt list --upgradable' to see them.
+```
+Also, 20 Paketen können aktualisiert werden.
+```bash
+sudo apt upgrade
+...
+The following packages will be upgraded:
+  bind9-dnsutils bind9-host bind9-libs buildah dnsutils firefox-esr golang-go golang-src iproute2 libdw1 libelf1 libtasn1-6 openjdk-17-jdk openjdk-17-jdk-headless openjdk-17-jre
+  openjdk-17-jre-headless vim-common vim-tiny xxd yt-dlp
+20 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
+...
+```
+
+#### **Paketinstallation und -entfernung**
+- **Suche nach einem Paket mit „transfer“**
+```bash
+apt search transfer
+...
+curl/parrot6-backports,now 8.11.1-1~bpo12+1 amd64 [installed,automatic]
+  command line tool for transferring data with URL syntax
+...
+```
+- **Installation von `curl`**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $sudo apt install curl
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+curl is already the newest version (8.11.1-1~bpo12+1).
+curl set to manually installed.
+```
+
+Also Paket curl war schon installiert.
+
+- **Entfernen von `tree`**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $sudo apt remove tree
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+The following packages were automatically installed and are no longer required:
+  golang-1.22-go golang-1.22-src
+Use 'sudo apt autoremove' to remove them.
+The following packages will be REMOVED:
+  tree
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+After this operation, 116 kB disk space will be freed.
+Do you want to continue? [Y/n] y
+(Reading database ... 353458 files and directories currently installed.)
+Removing tree (2.1.0-1) ...
+Processing triggers for man-db (2.11.2-2) ...
+Scanning application launchers
+Removing duplicate launchers or broken launchers
+Launchers are updated
+```
+
+Überprüfung der Entfernung:
+```bash
+┌─[user@parrot]─[~]
+└──╼ $apt-cache policy tree
+tree:
+  Installed: (none)
+  Candidate: 2.1.0-1
+  Version table:
+     2.1.0-1 600
+        600 https://deb.parrot.sh/parrot lory/main amd64 Packages
+```
+- **Neuinstallation von `tree`**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $sudo apt install tree
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+The following packages were automatically installed and are no longer required:
+  golang-1.22-go golang-1.22-src
+Use 'sudo apt autoremove' to remove them.
+The following NEW packages will be installed:
+  tree
+0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
+```
+- **System von nicht mehr benötigten Abhängigkeiten bereinigen**
+```bash
+# Liste der entfernten Pakete:
+┌─[user@parrot]─[~]
+└──╼ $sudo apt autoremove
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+The following packages will be REMOVED:
+  golang-1.22-go golang-1.22-src
+0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
+After this operation, 228 MB disk space will be freed.
+Do you want to continue? [Y/n] y
+(Reading database ... 353458 files and directories currently installed.)
+Removing golang-1.22-go (1.22.11-1~bpo12+1) ...
+Removing golang-1.22-src (1.22.11-1~bpo12+1) ...
+Scanning application launchers
+Removing duplicate launchers or broken launchers
+Launchers are updated
+
+```
+
+#### **Abhängigkeitsverwaltung**
+- **Untersuchung der Abhängigkeiten von `curl`**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $apt-cache depends curl
+curl
+  Depends: libc6
+  Depends: libcurl3-gnutls
+  Depends: zlib1g
+```
+---------------------------
+In der Ausgabe des Befehls `apt-cache depends curl` sehen wir die zwingenden Abhängigkeiten (Depends) für das Paket curl.
+
+#### Zwingende Abhängigkeiten (Depends)
+
+Diese Pakete müssen installiert sein, damit curl funktioniert:
+  - libc6 – Die Standard-C-Bibliothek für Linux
+  - libcurl3-gnutls – Die Bibliothek, die curl die Fähigkeit gibt, Netzwerkverbindungen über verschiedene Protokolle (HTTP, FTP, etc.) herzustellen.
+  - zlib1g – Eine Bibliothek zur Datenkompression
+
+#### Optionale Abhängigkeiten (Recommends oder Suggests)
+
+Diese werden nicht automatisch benötigt, können aber nützlich sein:
+
+- Recommends: Automatisch mitinstalliert, aber entfernbar.
+- Suggests: Werden empfohlen, sind aber nicht zwingend.
+----
+- **Defekte Abhängigkeiten reparieren**
+```bash
+# Simuliert die Reparatur
+┌─[user@parrot]─[~]
+└──╼ $sudo apt-get -s install -f
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
+```
+
+#### **Erweiterte Paketverwaltung**
+- **Verfügbare Versionen von `curl` anzeigen**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $apt-cache policy curl
+curl:
+  Installed: 8.11.1-1~bpo12+1
+  Candidate: 8.11.1-1~bpo12+1
+  Version table:
+ *** 8.11.1-1~bpo12+1 599
+        599 https://deb.parrot.sh/parrot lory-backports/main amd64 Packages
+        100 /var/lib/dpkg/status
+     7.88.1-10+deb12u9 600
+        600 https://deb.parrot.sh/parrot lory/main amd64 Packages
+     7.88.1-10+deb12u5 600
+        600 https://deb.parrot.sh/direct/parrot lory-security/main amd64 Packages
+```
+- **Spezifische Version installieren**
+```bash
+┌─[✗]─[user@parrot]─[~]
+└──╼ $sudo apt-get install curl=7.88.1-10+deb12u5
+Reading package lists... Done
+Building dependency tree... Done
+Reading state information... Done
+Some packages could not be installed. This may mean that you have
+requested an impossible situation or if you are using the unstable
+distribution that some required packages have not yet been created
+or been moved out of Incoming.
+The following information may help to resolve the situation:
+
+The following packages have unmet dependencies:
+ curl : Depends: libcurl4 (= 7.88.1-10+deb12u5) but 8.11.1-1~bpo12+1 is to be installed
+E: Unable to correct problems, you have held broken packages.
+```
+
+Also es erscheint nur möglich, die letzte Version zu installieren.
+
+- **`curl` für automatische Updates sperren**
+```bash
+┌─[✗]─[user@parrot]─[~]
+└──╼ $sudo apt-mark hold curl
+curl set on hold.
+
+# Überprüfung der Sperrung
+┌─[user@parrot]─[~]
+└──╼ $apt-mark showhold
+curl
+```
+- **Sperrung aufheben**
+```bash
+┌─[user@parrot]─[~]
+└──╼ $sudo apt-mark unhold curl
+Canceled hold on curl.
+```
+
+#### **Wichtige Befehle und ihre Bedeutung**
+| Befehl                      | Bedeutung |
+|-----------------------------|-----------|
+| `sudo apt update`           | Aktualisiert die Paketlisten |
+| `sudo apt upgrade`          | Aktualisiert alle installierten Pakete |
+| `sudo apt install <paket>`  | Installiert ein Paket |
+| `sudo apt remove <paket>`   | Entfernt ein Paket |
+| `apt-cache depends <paket>` | Zeigt Abhängigkeiten eines Pakets |
+| `sudo apt-mark hold <paket>` | Verhindert automatische Updates für ein Paket |
+| `sudo apt autoremove`       | Entfernt ungenutzte Abhängigkeiten |