Unix Tips

iTerm 2

To set the window title to the current directory: export PROMPT_COMMAND='echo -ne "\033]0;${PWD/#$HOME/~}\007"'

NordVPN

Setup

Install OpenVPN: sudo dnf install openvpn
Go to /etc/openvpn
sudo wget https://downloads.nordcdn.com/configs/archives/servers/ovpn.zip
sudo unzip ovpn.zip
sudo rm *.zip

Connecting to NordVPN

Go to https://nordvpn.com/servers/ and select "Recommend Server"
cd /etc/openvpn/ovpn_udp
sudo openvpn <recommended_server>.udp.ovpn
- If you're on a network that doesn't allow UDP connections, you can try the same thing in /etc/openvpn/ovpn_tcp and <recommended_server>.tcp.ovpn

RTorrent

Add torrent: <backspace>
To add torrent in inactive mode: <return>
To changed the directory of an inactive torrent:
- Select the torrent
- Ctrl-S
To stop a download: Ctrl-k
To remove a torrent: Ctrl-d
To quit: Ctrl-q
To select torrents: up/down
To set the priority of a torrent: +/-

ImageMagick

Create a PNG image with some text

convert -background none -font <font_name>.ttf -fill black -pointsize 150 -size "256x256" -gravity center label:"<text>" <output_file_name>.png

Change image formats:

convert file.<input extension> file.<output extension>

Tmux

Change the leader key to M-o because emacs uses C-b:

  unbind C-b
  set-option -g prefix M-o
  bind-key M-o send-prefix

Disable the clock in the tmux status bar: set -g status-right ''
Alternatively, set the clock to a simple day and date: set -g status-right ' %F %l:%M %p ' (note the space padding to aid legibility)
Set window title: M-o ,
Window management
- Create window: M-o c
- Next window: M-o n
- Previous window: M-o p
- Last used window: M-o l
- Choose window from list: M-o w
- Force quit the current window: M-o &
Helpful keybindings
- Reorder windows:
```
       bind-key -n C-S-Left swap-window -t -1
       bind-key -n C-S-Right swap-window -t +1 
```
- Switch windows
```
       bind-key -n S-Left previous-window
       bind-key -n S-Right next-window 
```
- Then you can use C-S-<left>/<right> to reorder windows and Shift-Left/Right to jump between windows
  - KDE Konsole defines these keys for switching between tabs, so you'll have to go into Settings -> Configure Shortcuts and unbind the Next Tab and Previous Tab shortcuts
Scrollback
- To scroll in tmux, enter scroll mode: M-o [
- To leave scroll mode: q
- To increase the amount of scrollback tmux buffers: set-option -g history-limit <number of lines>
tmux expects your bash startup to be in ~/.bash_profile
Renumber windows: set-option -g renumber-windows on

Change the active window highlight

 
      set-option -g window-status-format "#I:#W"
      set-option -g window-status-current-style "fg=green bg=black"

To prevent tmux from renaming windows automatically: set-option -g allow-rename off
To reload the config without restarting tmux: M-o :source-file ~/.tmux.conf~
tmux plugin manager
- git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm
- Add the following to the bottom of ~/.tmux.conf
```
       set -g @plugin 'tmux-plugins/tpm'
       run -b '~/.tmux/plugins/tpm/tpm' 
```
Copy/Paste
- Go into scrollback mode M-o [
- Hit Ctrl-<SPC> to enter select mode
- Use arrow keys to select
- Hit Alt-W to copy
- Hit M-o ] to paste
- To integrate tmux with the system clipboard, install the tmux yank plugin
  - Add set -g @plugin 'tmux-plugins/tmux-yank' to ~/.tmux.conf
  - Install the plugin with M-o Shift-I
  - To use:
    - M-o Y copies the current command line
    - In select mode y copies the selection to the system clipboard
Clear scrollback: M-o :clear-history
Split panes:
- Horizontal split: M-o "
- Vertical split: M-o %
- Switch panes: M-o <arrow key>
- To convert a window into a pane in the current window: M-o :join-pane -t <target window number>
- To convert a pane back into a window: M-o !
- Change layouts: M-o <space>

Shell

List only directories

ls -d */
find . -maxdepth 1 -type d

Get the current time in milliseconds

date +3N
On MacOS, there is on %N option, so we just hack it by adding three zeroes to the time in seconds: date +%s000

Get the nth line of a file

cat <file> | sed -n "<line num>p"
Example: to print the 10th line of a file:
```
      cat foo.txt | sed -n "10p"
```

Aliases

Date and time: alias d="date '+M %p'" — writes the current time in an easy-to-read format

Local Web Server

python3 -m http.server

Manual IP Address Configuration

Temporarily

Set the IP address:

       ifconfig <interface> address <address>
       ifconfig eth1 address 172.16.64.2

Set the subnet mask:

       ifconfig <interface> netmask <subnet_mask>
       ifconfig eth1 netmask 255.255.192.0

Permanently

Edit /etc/network/interfaces

       auto <interface>
       iface <interface> inet static
           address <ip_address>
           netmask <netmask>

Example:

       auto eth1
       iface eth1 inet static
           address 172.16.64.2
           netmask 255.255.192.0

Configure Passwordless Logins

Add your SSH public key to ~/.ssh/authorized_keys on the target server

DC Calculator

Viewing the stack
- p prints the value at the top of the stack without altering the stack
- n pops the value at the top of the stack and prints it without printing a newline
- P pops the value at the top of the stack and prints it with a newline
- f prints the entire stack without altering it
Arithmetic
- k pops the first value off the stack and uses it to set the precision
- + pops two values off the stack, adds them and pushes the result on to the stack
- - pops two values off the stack and subtracts the first from the second and pushes the result onto the stack
- * pops two values off the stack, multiplies them, and pushes the result onto the stack
- / pops two values off the stack, divides the second by the first and pushes the result onto the stack
Stack control
- r swaps the two values at the top of the stack
- d duplicates the value at the top of the stack and prints it
- c clears the stack

List all installed packages on Fedora

dnf list installed

Select a random value

<list command> | shuf -n 1
Example: Choose a random file: ls -1 | shuf -n 1

MPV

Usage: mpv <video filename>
Controls
- <left> / <right>: Skip backwards/forwards by 5 seconds
- Shift-<left> / Shift-<right>: Skip backwards/forwards by 1 second
- <up> / <down>: Skip back/forward by 1 minute
- Ctrl-<left> / Ctrl-<right>: Switch to previous/next subtitle language
- <SPC>: Pause/unpause
- q: quit
- f: fullscreen
- 9 / 0: Lower/raise volume
- v: Toggle subtitle visbility
- #: Change audio track
To specify a subtitle file: --sub-file=<filename>
- To adjust subtitle delay:
  - Ctrl-Shift-<left>: Displays previous subtitle and adjusts subtitle delay
  - Ctrl-Shift-<right>: Displays next subtitle and adjusts subtitle delay
To rescale videos
- --autofit=<width>[x<height>]: Sets the width (and height) to a particular value while maintaining aspect ratio; if both width and height are specified, it uses the minimum of width and height meet the aspect ratio requirement
- --autofit-larger=<width>[x<height>]: Like autofit, but only rescales the video if it would be larger than the specified dimensions
Playlists:
- Create a file with video filenames separated by newlines
- Pass the playlist file to mpv with the --playlist argument

rsync

To sync all files of a particular type: rsync -t <user>@<host>:/path/to/directory/*glob* .
To recursively sync all files in a directory: rsync -rt ./* <user>@<host>:/path/to/directory

Hostname

To set the hostname: sudo hostnamectl set-hostname <new_hostname>

GNU Find

To exec a program on every found file:
- find . -iname <glob> -exec <program> {} +
- find . -iname <glob> -exec <program> {} \;
- The first form passes all found files to the program as command line args
- The second form invokes the program repeatedly, once per file
To exclude directories/paths from find:
- find . $-path <path 1> -or -path <path 2> -or ... $ -prune -or -iname <glob> -print
- If using the -exec, replace -print with -exec
To exclude particular file types:
- $ -iname "<glob>" ! -iname "<exclude_glob>" $
- Example: To find all .js files but exclude tests: find . $ -iname "*.js" ! -iname "*.test.js" $ -print

GNU Grep

To eliminate "binary file matches" messages: -I
To just list files instead of each matching line: -l

Synaptics touchapd customization:

To set up two-finger click correctly: synclient RightButtonAreaLeft=0 RightButtonAreaTop=0 ClickFinger2=3

Automatically set up power management:

Install PowerTop: sudo dnf install powertop

Create the following systemd init file:

  [Unit]
  Description=PowerTop Auto Tune

  [Service]
  Type=idle
  Environment="TERM=dumb"
  ExecStart="/usr/sbin/powertop --auto-tune"

  [Install]
  WantedBy=multi-user.target

cURL

Download a file: curl -o <file_name> <URL>
To make cURL silent, add the -s flag
To add headers, use the -H flag: -H "header_name: header_value"
If you need to specify multiple headers, use multiple instances of the -H flag
If the file is mangled, try adding --compressed
You can also go into Chrome's devtools and select "Copy As cURL"

RPM Fusion repo:

To install RPM Fusion:

  sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm

Clipboard

Copy contents of file into clipboard:
- MacOS: pbcopy < <file>
- Linux: cat <file> | xsel -ib
Paste contents of clipboard into file:
- MacOS: pbpaste > <file>
- Linux: xsel -ob > <file>

WeeChat setup with weechat.el

Set up weechat
- sudo apt install weechat
- Launch weechat: weechat
- Configure basic settings
  - Configure IRC server: /server add freenode chat.freenode.net
  - Configure SASL username: /set irc.server.freenode.sasl_username quanticle
  - Configure SASL password: /set irc.server.freenode.sasl_password <password>
  - Configure channels to autojoin: /set irc.server.freenode.autojoin <comma separated list of channels>
- Configure weechat relay
  - Configure relay password: /set relay.network.password <password>
  - Create an SSL key for the relay:
    - mkdir -p ~/.weechat/ssl
    - cd ~/.weechat/ssl
    - openssl genrsa 2048 > relay.key
    - openssl req -new -x509 -nodes -days 365 -key relay.key > relay.cert
    - cat relay.key relay.cert > relay.pem
  - Tell weechat to use the new SSL cert: /relay sslcertkey
  - Set up the weechat relay port: /relay add ssl.weechat 9899
- Disable weechat colors: /set weechat.color.chat_nick_colors gray
- Set up logging: /set logger.level.irc.freenode 3
- Set up highlight monitoring
  - /script install highmon.pl
  - /set plugins.var.perl.highmon.away_only on

Set up emacs:

Install weechat.el: M-x package-install RET weechat
Copy in cert file: scp <weechat_server>:/home/quanticle/.weechat/ssl/relay.cert ~/.emacs.d/relay.cert

In ~/.emacs.d/init.el:

   (require 'weechat)
   (require 'gnutls)
   (add-to-list 'gnutls-trustfiles (expand-file-name "~/.emacs.d/relay.cert"))
   (set-face-attribute weechat-nick-self-face nil :foreground 'unspecified  :weight 'unspecified)

To use weechat.el: M-x weechat-connect RET
Disable timestamps in weechat message buffer: /set weechat.look.buffer_time_format ""

Clojure setup

Install rlwrap
Install the latest OpenJDK JRE

Install Clojure:

  curl -O https://download.clojure.org/install/linux-install-1.10.1.502.sh
  chmod +x ./linux-install-1.10.1.502.sh
  sudo ./linux-install-1.10.1.502.sh

Test to see if Clojure is installed by running: clojure to get the REPL