Latest "Shell commands" files
Workshop » Reference Section » Grimoires » IT » Platforms » MacOS » Networking

SSH into local mac, error “WARNING- REMOTE HOST IDENTIFICATION HAS CHANGED!”

SSHing into a local MacOS machine at address "macbook.local", I suddenly got this:

[code]@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has just been changed. The fingerprint for the ED25519 key sent by the remote host is SHA256:oKCEu3pDdq7xBhSPZwOzR2q0eWTvfphtvn3D4Bjz8v4. Please contact your system administrator. Add correct host key in /Users/username/.ssh/known_hosts to get rid of this message. Offending ECDSA key in /Users/username/.ssh/known_hosts:147 Host key for macbook.local has changed and you have requested strict checking. Host key verification failed.[/code]

The solution was to run ssh-keygen -R macbook.local then try the ssh again. Then it asked me whether or not to accept the key, instead of rejecting it:

[code]$ ssh username@macbook.local The authenticity of host 'macbook.local (fe80::1890:fd32:c304:69cd%en0)' can't be established. ED25519 key fingerprint is SHA256:oKCEu3pDdq7xBhSPZwOzR2q0eWTvfphtvn3D4Bjz8v4.…
Workshop » Reference Section » Grimoires » IT » Platforms » Linux » Packages » PHP

Enable PHP 8.4 in Apache on Debian

According to the installer, to enable PHP 8.4 FPM in Apache2 do:
a2enmod proxy_fcgi setenvif
a2enconf php8.4-fpm

Workshop » Reference Section » Grimoires » IT » Platforms » Linux » Packages » rsync & rsnapshot

How to backup a WordPress site via SSH

To make a complete local backup of a remote WordPress install over SSH, you need to perform two distinct steps:

  1. Download the files (using rsync).
  2. Export and download the database (using mysqldump piped through ssh).

Here is the step-by-step guide.

Prerequisites
  • SSH Access: You need the username, host (IP or domain), and password (or SSH key) for the remote server.
  • WordPress Path: You need to know where WordPress is installed (e.g., /var/www/html or /home/user/public_html).
  • Database Credentials: You will need the database name, user, and password. (I will show you how to find these below).
Step 1: Find Database Credentials (Optional)

If you don't know your database login details, run this command to read them from your remote wp-config.php file: ssh user@remote-server.com "cat /path/to/wordpress/wp-config.php" | grep 'DB_'

Note the DB_NAME, DB_USER, and DB_PASSWORD for Step 2.

Step 2: Download the Database (SQL Dump)…
Workshop » Reference Section » Grimoires » IT » Platforms » Linux » Packages » rsync & rsnapshot

Post-migration steps when migrating or restoring Linux from backup

There are intentionally vague broad steps, here just as a reminder to myself; best to look specific instructions for each of these steps up at restore time for the particular system you're restoring to.

A.) Backups should include all user data. Depending on who you ask, that's either:
1.) The entire filesystem except /dev/*, /proc/*, /sys/*, /tmp/*, /run/*, /mnt/*, /media/*, /lost+found (which can be pulled from a complete filesystem backup with rsync -avhP --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found"} /mnt/olddrive/ /mnt/netdrive/)
2.)/home, /etc (except /etc/passwd and /etc/groups, these have useful information to back up but may conflict if written to a new install), /usr/local, /opt, /root, /var (exluding /var/tmp, /var/run/, /var/lock, or /var/spool except you DO want /var/spool/cron/crontabs/)

B.) After copying all the above to the new or restored disk, you need to update /etc/fstab with the new disk UUIDs.

C.) Install GRUB Bootloader.

D.) If you're using LUKS encryption, set that…

Workshop » Reference Section » Grimoires » IT » Platforms » Linux » Packages » rsync & rsnapshot

Fastest way to delete a large, deep directory in Linux

Per numerous references around the web, to delete /path/to/directory-to-delete/:

 cd /path/to/ mkdir empty_dir rsync -a --delete empty_dir/ directory-to-delete/ rm -r empty_dir rm -r directory-to-delete 

Disclaimer: this is for my own reference, not recommended for your use. Use it at your own risk. If I am wrong—and I may be—these commands can do tremendous damage to your system.