Linux

Linux is the standard OS for deploying software today.

Tips and Tricks

SSH Agent Forwarding

This is useful if you use another machine on the network to do "heavier" work

Setting up SSH agent forwarding

Modify the ~/.ssh/config file. If one doesn't exist, you can create it by entering touch ~/.ssh/config

Enter the following example in the config file

  Host [example.com]
    ForwardAgent yes

Ensure that your /etc/ssh/config file is set up for forwarding

Your config file should look like this

# ForwardAgent no
  Host *
    SendEnv LANG LC_*

Notice that the ForwardAgent no line is commented out with the # in front of it

Executing the commands

Ensure that your ssh-key is loaded

ssh-add [your key location]

SSH to the machine that you have set up

ssh -A [username]@[example.com]

Memory

Show memory slots being used

dmidecode -t memory

Show how many slots are available

dmidecode -t memory | grep -c "Memory Device"

Show how many slots are not used

dmidecode -t memory | grep -c "Size: No Module Installed"

Extract all RAR files in a directory

for file in *.rar; do unrar e "$file"; done

Clear out a log file

sudo < /var/log/somelogfile.txt

Show disk use but only at the top level

sudo du -h -x -d 1 /[some directory name]

Remove application config for user

rm -rf ~/.config/[application name]

Expanding disk space leveraging LVM

Remove duplicate entry from known_hosts

ssh-keygen -f "/home/kelvin/.ssh/known_hosts" -R "windcharger-desktop"

Process Management

Kill all processes related to an application name

killall [some app name]

Utilities

tmux

tmux is a terminal multiplexer. It lets you switch easily between several programs in one terminal, detach them (they keep running in the background) and reattach them to a different terminal.

Creating a bootable USB key from the command line

sudo dd bs=4M if=/path/to/isoimage.iso of=/dev/sdx status=progress oflag=sync