Thanks head on a stick, i forgot to do that. This has been a good learning experience and its good to make mistakes and learn from them. I will definitely be looking into more posix orientated scripts in the future. Updated the script as per shellcheck.

that seems to be the case. Thanks again.

Yes that seems to work as well. Im having a hard time wrapping my head around this stuff, thanks.

Managed to cobble this together, not in anyway portable but ill keep trying.
something interesting i found out, luks header keys takes up 16 mb of space so you cant have have a small img like 10mb.

NAME           MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
loop0            7:0    0    20M  0 loop
└─cryptfs      254:1    0     4M  0 crypt /home/$u/crypt

Need to look into better command structure using more positional parameters, especially with the use of the crypt.img?
Find out how to use getopts usage better.

#!/bin/bash
set -x
u="<username>"
outfile="$2"
blocksize="$3"

crypt_img () {
	dd if=/dev/urandom of=$outfile bs=$blocksize count=1 iflag=fullblock
}

crypt_create () {
	losetup --find
	losetup /dev/loop0 crypt.img
	cryptsetup luksFormat crypt.img
	cryptsetup open crypt.img cryptfs
	mkfs.ext4 /dev/mapper/cryptfs
}

crypt_open () {
	cryptsetup open crypt.img cryptfs
}

crypt_mount () {
	mount -t ext4 /dev/mapper/cryptfs /home/$u/crypt
}

crypt_umount () {
	umount /home/$u/crypt
	cryptsetup close cryptfs
	losetup -d /dev/loop0
}

while getopts ":iComu" opt; do
  case ${opt} in
    i ) crypt_img $2 $3
      ;;
    C ) crypt_create
      ;;
    o ) crypt_open
      ;;
    m ) crypt_mount
      ;;
    u ) crypt_umount
      ;;
    \? ) echo "Usage: cmd [-i] [-C] [-o] [-m] [-u]"
      ;;
  esac
done

this is the script im working on, im stuck on the dd command as its giving me  dd: invalid number: ‘test.img’  when i run
sudo ./script.sh -C test.img 10 1
This has to be run via root or sudo, could be an issue there.

Im hoping to turn those crypt_open and crypt_close functions for the .img into positional parameters somehow.

EDIT: oops i need to also figure out cryptsetup creation. Ignore this post, keep it here for learning purposes.

#!/bin/bash

outfile="$2"
blocksize="$3"

create () {
        dd if=/dev/urandom of=$outfile bs=$blocksize count=1 iflag=fullblock
}

crypt_open () {
        losetup /dev/loop0 /home/$USER/ecrypt.img
        cryptsetup open /dev/loop0 ecryptfs
        mount -t ext4 /dev/mapper/ecryptfs /home/$USER/crypt/

}

crypt_close () {
        umount /home/$USER/crypt
        cryptsetup close ecryptfs
        losetup -d /dev/loop0

}

while getopts ":ocC" opt; do
  case ${opt} in
    o ) crypt_open
      ;;
    c ) crypt_close
      ;;
    C ) create $2 $3
      ;;
    \? ) echo "Usage: cmd [-o] [-c] [-C]"
      ;;
  esac
done

EDIT2; fixed dd function for getopts

I suppose the default gateway is the way to go, so if wlan0 is connected first and then usb0, the default is always going to be wlan0 and vice versa, would that be true?. I wonder how conky does the gw_iface object though.

In regards to ifconfig, atleast in my case on devuan beowulf, if wlan0 is not connected it wont show up in ifconfig, only lo. where ip l all interfaces are shown regardless if they are up or down.

In regards to why is it in the kernel, i should have referenced the answer i got from stackoverflow. I know it is part of the net-tools package so i was confused about this quote:

In regards to ip, i have some issues with ip l , the difference being that ip l shows ifaces even if they are down whereas ifconfig and netstat does not. So this would make the script only output multiple if ip was used.

Here is ip l on my machine with usb0 and wlan0, with only wlan0 up.

ifconfig
lo: flags=73<UP,LOOPBACK,RUNNING>
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>

netstat -i
Kernel Interface table
Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
lo       65536        0      0      0 0             0      0      0      0 LRU
wlan0     1500      810      0      0 0           724      0      0      0 BMRU

ip l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DORMANT group default qlen 1000
4: usb0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000

I have used slstatus in the past, i may revert back to it again, although this endeavor was just to see if i could create shell scripts to pipe to dwm statusbar instead, which i have accomplished.

created a network iface script for this statusbar script. This kind of similar to how conky does it with -

I was told over at stackoverflow i shouldnt be using ifconfig for something as simple as this, which i think is ridiculous, if i wanted to do fancy stuff with the networks i would use iproute2 but for this, not needed. If it is old and deprecated why is it still in the kernel?

This will print on my statusbar as follows,

• If usb net connected = usb0

• If wlan0 connected = wlan0

• If both usb and wlan0 connected =multiple

• If no network = not connected

#!/usr/bin/env bash

a=$(ifconfig | grep -ow "wlan0\|usb0")
b=$'wlan0\nusb0'
c="%printf '$b'"

if      [[ "$a" = "wlan0" ]] ; then
        printf "wlan0"

elif    [[ "$a" = "usb0" ]] ; then
        printf "usb0"

elif    [[ "$a" =~ ["$c"] ]] ; then
        printf "multiple"

else
        printf "not connected"
fi

Can these appimages be used in software centers like gnome software or kde etc? Ive never used them, just curious how they are got.

messing around with a minimal exit menu script.

get_exit () {
read -n 1 -p "(e)xit, (r)eboot, (s)hutdown, (l)ock  " exit;

case $exit in
    e)
       pkill xinit;;
    r)
        sudo reboot;;
    s)
        sudo poweroff;;
    l)
       xscreensaver-command -l;;
esac

}

this could be a separate script as well, ive called an xterm using the following line as a keybind from my window manager. This places a small xterm in the center of the screen and all i need do is press whatever button needed or press escape to quit the xterm.

xterm -geo 50x1+400+300 -e exit-menu

and therein is the answer. This is why i dislike where gnome is heading.