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--- helpful_ubuntu_commands [2026/03/22 10:00] – mike
+++ helpful_ubuntu_commands [2026/08/08 20:15] (current) – mike
@@ Line 1: / Line 1: @@
 ====== Helpful Ubuntu/Linux Commands and Procedures ======
-----
+==== Miscellaneous/General Commands ====
 === Disable Ubuntu Pro "Ads", Etc. ===
-<color red>First implemented in my network 03/20/2025; monitoring for effectiveness</color>
   sudo pro config set apt_news=false
@@ Line 42: / Line 42: @@
 === Determine the date the system was installed (not 100% reliable) ===
   tune2fs -l /dev/vda2 | grep ‘Filesystem created:’ (replace vda2 with device where root filesystem is located)
+=== Copy an existing partition to a new partition ===
+  sudo rsync -aAXv --info=progress2 --exclude='/lost+found' /disk2/ /newdisk/
 === Finding largest files/directories ===
   du -a /dir/ | sort -n -r | head -n 20 (replace 20 with the # of lines you wish to have returned)
@@ Line 55: / Line 58: @@
   Create (or edit, if it exists) ~/.vimrc; into this file add the command syntax off, and save the file.
-**Overwrite/blast the boot block on the hard drive (<color red>ONLY when you want to re-install the operating system!</color>)**
-  dd if=/dev/zero of=/dev/sda count=1 bs=512
 === Find files consuming the root file system ===
   mkdir /tmp/rootbind
@@ Line 73: / Line 72: @@
 OTA DVR recordings are saved as **.ts** files, which are not compatible with DaVinci Resolve (my video editor of choice).  For this reason, we must convert the files into a format that “DR” can comprehend.  We can do this on linux using the ffmpeg package:
   ffmpeg -i <inputfile.ts> -vcodec copy -acodec copy <outputfile.mp4>
+**Overwrite/blast the boot block on the hard drive (<color red>ONLY when you want to re-install the operating system!</color>)**
+  dd if=/dev/zero of=/dev/sda count=1 bs=512
+==== Ansible/Automation Related Info ====
 === Generate password hashes (useful for Ansible playbooks amongst other things) ===
   mkpasswd --method=sha-512
+=== Generate random keys ===
+  openssl rand -base64 48
+=== Example of referencing an Ansible Vault ===
+  ansible-playbook playbook.yml --vault-password-file ~/.ansible_vault_pass
 ==== Extracting encrypted/password protected .ZIP files ====
@@ Line 101: / Line 112: @@
 Restart apache.
-=== Create new GPT disk partition ===
+==== Create new GPT disk partition ====
 sudo into an elevated shell and then perform the following:
   parted /dev/sdX (where X is the letter of the drive to be manipulated)
@@ Line 126: / Line 137: @@
 Edit the **/etc/netplan/50-cloud-init.yaml** file appropriately (file name may vary)\\
 Apply the changes with the **sudo netplan apply** command
+=== Disabling the local DNS resolver ===
+This becomes necessary if a DNS server is deployed on the local system, since it will conflict with the local resolver unless it is first disabled.
+Edit **/etc/systemd/resolved.conf** and change **//DNSStubListener//** to "no":
+  DNSStubListener=no
+Update the **resolv.conf** symlink:
+  sudo ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf
+Restart **systemd-resolved**:
+  sudo systemctl restart systemd-resolved
+Validate that the system is no longer listening on port 53:
+  ss -tulpn | grep 53
+==== Creating SSH Keys ====
+To create an ed25519 key -
+  ssh-keygen -t ed25519 -C "<comment>" -f ~/.ssh/<keyname>