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A dumping ground for basic gnulinux sysadmin and other miscellaneous notes, or miscadmin for short.
-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
-youtube-dl-
sudo curl -L https://yt-dl.org/downloads/latest/youtube-dl -o /usr/local/bin/youtube-dl sudo chmod 750 /usr/local/bin/youtube-dl
-optical ripping example-
cdrecord -pad -dao -data blag-140k-i686.iso
-pam hardening location-
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 and other-
exim -bp <print message ids> exim -Mrm <message id> exim -bp | awk '/^ *[0-9]+[mhd]/{print "exim -Mrm " $3}' | bash use this for local interfaces for ipv6 ::::0:0.0.0.0 view exim -Mvh
-verifying TLS with swaks on exim4 relay setup
swaks -a -tls -q HELO -s smtp.haacksnetworking.com:587 -au test -ap '<>'
-mysql password-
nano /etc/mysql/debian.cnf sudo mysql -u debian-sys-maint
-temporary name servers - how to add some - temporary/permanent syntax below:
echo "nameserver 4.2.2.1" | sudo tee /etc/resolv.conf > /dev/null echo "nameserver 4.2.2.1" | sudo tee /etc/resolvconf/resolv.conf.d/base > /dev/null
-strip desktop environments from GUI system
tasksel --list-tasks tasksel --task-packages desktop sudo apt-get purge $(tasksel --task-packages desktop)
-deborphan
sudo apt install deborphan sudo apt-get remove `deborphan` for i in `deborphan`; do apt-get --purge remove -y $i; done
-checking ssh logs
cat /var/log/auth.log | grep 'sshd.*Invalid' cat /var/log/auth.log | grep 'sshd.*opened'
— oemb1905 2019/11/02 20:56