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computing:sysadmin-notes

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  • sysadmin-notes
  • Jonathan Haack
  • Haack's Networking
  • netcmnd@jonathanhaack.com

A dumping ground for basic gnulinux sysadmin and other miscellaneous notes


-Text Editors-

Change the default text editor, terminal, web browser, in Debian

exo-preferred-applications

Some systems are not kind with exo, so …

xdg-mime default caja.desktop inode/directory application/x-gnome-saved-search

Set caja or other file managers to manage desktop

gsettings set org.gnome.desktop.background show-desktop-icons false
gsettings set org.nemo.desktop show-desktop-icons true

-motd-

Create the following to make a message of the day that will be appended to the dynamic message of the day.

sudo nano /etc/motd

Is motd printing twice, comment out motd statis in pam setting

/etc/pam.d/sshd
#session    optional     pam_motd.so noupdate
(actually it is the line above this, leave this active)

Print motd with every shell log in …

nano ~/.bashrc

Navigate to the end of the file, and add

cat /etc/motd

-Firefox-

To install the latest firefox on Debian and make it default, do the following. The link below may not always work, so replace when updated.

sudo mkdir -p /opt/firefox
sudo chown -R $USER:$USER /opt/firefox
cd ~/Downloads && wget -O FirefoxSetup.tar.bz2 "https://download.mozilla.org/?product=firefox-latest&os=linux64&lang=en-US"
tar xjf FirefoxSetup.tar.bz2 -C /opt/firefox/
sudo mv /usr/lib/firefox-esr/firefox-esr /usr/lib/firefox-esr/firefox-esr_orig
sudo ln -s /opt/firefox/firefox/firefox /usr/lib/firefox-esr/firefox-esr

To restore firefox-esr that comes with Debian.

unlink /usr/lib/firefox-esr/firefox-esr
mv /usr/lib/firefox-esr/firefox-esr_orig /usr/lib/firefox-esr/firefox-esr

-optical ripping-

cdrecord -pad -dao -data blag-140k-i686.iso

-pam garbage-

sudo nano /etc/pam.d/common-password

Prevent Log in - create file

/etc/nologin

-old reminders-

remove old and offending keyring from gnome, make new directory for new one

sudo rm -rf ~/.local/share/keyrings
mkdir ~/.local/share/keyrings

start or stop network manager (or other services)

systemctl <start/stop/restart> networkmanager.service
/etc/init.d/network-manager <start/stop/restart>

verify dhcp client working for interface eno1

dhclient -v eno1

add subnet to interface eno1

ip address add 192.1##.1##.2/24 dev eno1

interface tool w/ eno1 example

ethtool eno1  

interface with switch using screen

screen /dev/ttyUSB0/ 19200

calculate subnet automatically

subnetcalc

proxying web traffic through remote server

ssh -D <port#> <user>@<domain.com>

get block ID of drives

blkid

nmap to scan devices on lan

nmap -sP 10.##.##.0/24

find utils example

find . -iname "name" 

-ngrok-

ngrok notes; private http(s) tunnels

./ngrok http 80
wget https://[ngrok tunnel]/id_rsa.pub
cat ~/id_rsa.pub >> ~/.ssh/authorized_keys

query hosts on the lan

avahi-browse -tl _workstation._tcp

Debian print system configuration to stdout; use root

cat /proc/cpuinfo && lspci | grep -i vga && uname -a && lsb_release -a
lsb_release -a
lspci

Debian repo management

cd /etc/apt
nano sources.lsit
[main contrib non-free]

-sftp basics-

cd ~/Downloads
sftp user@host.com:/path/to/sftp/directory/of/choice/
> put /path/to/file.txt 

-build app from source-

tar -xf <source_filename>

Navigate to the directory that tar unarchived the files to. Then, within that directory, execute:

./configure --prefix=/usr/local

make
sudo make install clean

-using vi to scrape unnecessary text strings away from openwrt packages that need updating

:1,$s/ .*//

-passing traffic through wifi radio to another interface on host-

sudo su -c "iptables -t nat -A POSTROUTING -o wlp2s0 -j MASQUERADE"
sudo su -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
set a static ip using ip a a x.x.x.x. dev blah
set static on wndr wan

-exim delete all messages-

exim -bp <print message ids>
exim -Mrm <message id>
exim -bp | awk '/^ *[0-9]+[mhd]/{print "exim -Mrm " $3}' | bash

-verifying TLS with swaks on exim4 relay setup

swaks -a -tls -q HELO -s smtp.schaeferconsulting.com -au test -ap '<>'

oemb1905 2019/08/08 17:52

computing/sysadmin-notes.1565546264.txt.gz · Last modified: 2019/08/11 17:57 by oemb1905