Shell Redirect

Discard the output Sometimes you will need to execute a command, but you don't want the output displayed on the screen. In such cases, you can discard the output by redirecting it to the file /dev/null − $ command > /dev/null Here command is the name of the command you want to execute. The file /dev/null is a special file that automatically discards all its input. To discard both output of a command and its error output, use standard redirection to redirect STDERR to STDOUT − $ command > /dev/null 2>&1 Here 2 represents STDERR and 1 represents STDOUT.


When set on a directory, Setting the setgid permission on a directory (e.g. "chmod g+s") it causes new files and subdirectories created within it to inherit its group ID, rather than the primary group ID of the user who created the file (the owner ID is never affected, only the group ID).

Setting up SSH to use key pairs

If you SSH to the same server a lot and don't want to type the password each time you can configure SSH so you don't have to.

First login to your terminal as normal and run

$ ssh-keygen

This will ask you the name of the key pair file you want to use.
It will suggest ~/.ssh/id_rsa
It will also create an file.

Next you need to "copy" that file to the server you want to connect to, you do by using the ssh-copy-id command.

$ ssh-copy-id user@hostname

SELinux and Ports

Here is an example of how ports are controlled by SELinux. Say that the port that apache uses was changed to 1000 when you start apache you get these errors [root@server01 conf]# systemctl status httpd httpd.service - The Apache HTTP Server Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled) Drop-In: /usr/lib/systemd/system/httpd.service.d └─php-fpm.conf Active: failed (Result: exit-code) since Tue 2019-10-29 19:34:11 AEDT; 5min ago Docs: man:httpd.service(8) Process: 26402 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILUR

SELinux and file contexts

apache root document folder was changed from normal folder to /repos folder attempting to get index.html resutls in an error [root@server01 repos]# curl localhost/index.html Forbidden You don't have permission to access /index.html on this server. set the correct context on the new folder [root@server01 repos]# semanage fcontext -a -t httpd_sys_content_t "/repos(/.*)?" check the context [root@server01 repos]# ls -laZ total 4 drwxr-s---.

How to manually update Plex in a FreeNAS jail

Pre-Update Steps Login to the servers as root Download the update to the server

1) change to the plexmeduaserver directory

root@plex:/ # cd/usr/local/share/plexmediaserver

2) stop the plexmediaserver service

root@plex:/usr/local/share/plexmediaserver # service plexmediaserver stop
Stopping plexmediaserver.
Cleaning up leftover child processes.

3) Copy the plex update to the current directory

3) Unzip the Plex update (the exact name of the update will be slightly different to what is shown


Ability Checks

To make an ability check, roll a d20 and add the relevant ability modifier. As with other d20 rolls, apply bonuses and penalties, and compare the total to the DC. If the total equals or exceeds the DC, the ability check is a success—the creature overcomes the Challenge at hand. Otherwise, it’s a failure, which means the character or monster makes no progress toward the objective or makes progress combined with a setback determined by the GM.

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