name="John"
echo ${name}
echo ${name/J/j}    #=> "john" (substitution)
echo ${name:0:2}    #=> "Jo" (slicing)
echo ${name::2}     #=> "Jo" (slicing)
echo ${name::-1}    #=> "Joh" (slicing)
echo ${name:(-1)}   #=> "n" (slicing from right)
echo ${name:(-2):1} #=> "h" (slicing from right)
echo ${food:-Cake}  #=> $food or "Cake"

#!/bin/bash

sudo apt install build-essential vulkan-tools libvulkan-dev vulkan-validationlayers-dev spirv-tools libglfw3-dev libglm-dev libtinyobjloader-dev

#The rest of this downloads the Vulkan Tutorial project and its dependencies.
#Comment this out to keep going
exit

sudo apt install git cmake cmake-gui

sudo mkdir /usr/lib/stb

pushd /usr/lib/stb

sudo wget https://raw.githubusercontent.com/nothings/stb/master/stb_image.h

popd

cd ~/Documents

git clone https://github.com/Overv/VulkanTutorial.git

cd VulkanTutorial/code

cmake -S . -B build -DCMAKE_INSTALL_PREFIX:PATH="/usr/local" -DSTB_INCLUDEDIR:PATH="/usr/lib/stb"

cd build

make

for region in `aws ec2 describe-regions --output text | cut -f4`
do
     echo -e "\nListing Instances in region:'$region'..."
     aws ec2 describe-instances --query 'Reservations[*].Instances[*].{Instance:InstanceId,Subnet:SubnetId}' --region $region
done
#This script is to be used with any AWS CLI configured environment, it will list any EC2 instances and their associated subnet network ID's in JSON format

#!/bin/bash
#cpcmd.sh [file1 [file2...]]
#Prints out the commands needed to copy the file to your local machine
#This will work on any server that also has the same hostname as in your hosts file.
#I should update this to detect if a file is a directory, and enable recursion for those commands. If you do it now, it will probably just warn you.
if [ -n "$1" ]; then
		while [ -n "$1" ]; do
				printf "scp \"$(whoami)@$(hostname):"
				printf `readlink -f $1`
				printf "\" .\n"
				shift
		done
else
		echo "scp \"$(whoami)@$(hostname):$PWD/*\" ."
fi

#-----------EDIT:
#On the UNT cell machines, you have to do this script instead
#if [ -n "$1" ]; then
#        while [ -n "$1" ]; do
#                printf "scp $(whoami)@$(hostname).eng.unt.edu:"
#                printf `readlink -f $1`
#                printf " .\n"
#                shift
#        done
#else
#        echo "scp $(whoami)@$(hostname).eng.unt.edu:$PWD/* ."
#fi

// check version
node -v || node --version

// list installed versions of node (via nvm)
nvm ls

// install specific version of node
nvm install 6.9.2

// set default version of node
nvm alias default 6.9.2

// switch version of node
nvm use 6.9.1

#!/bin/bash
#Originally made by Isaac Cook https://gist.github.com/icook/5400173
#Modified by Leif Messinger
#upload_key.sh [server_ip [server2_ip [...]]]
#To be run locally on a linux computer

if [ -e ~/.ssh/id_rsa.pub ];
then
    echo "SSH Key already exists on local machine"
else
    echo "Generating SSH key on local machine"
    ssh-keygen -t rsa   #generates id_rsa and id_rsa.pub
    chmod -R 700 ~/.ssh #Sets permissions of ssh folder
    ssh-add     #Adds keys (and passwords?) to ssh_agent. (hopefully doesn't require password)
fi

echo "Loading client public key into memory"
pubKey=$(<~/.ssh/id_rsa.pub)

for server
do
    echo "Adding client public key to $server remote server authorized keys"
    #Idiot Isaac Cook didn't know about ssh-copy-id
    #ssh-copy-id even checks if your key already exists
    #In fairness, I didn't either until researching ssh-add
    ssh-copy-id -i ~/.ssh/id_rsa.pub $server        #In theory, this should prompt for a username

    #ssh $server "mkdir -p ~/.ssh;  #Make the folder if not already made
    #       echo \"$pubKey\" >> ~/.ssh/authorized_keys;     #Append your public key to the server's authorized_keys
    #       chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys"   #Set the correct permissions of those files

    #echo "Adding server public key to local authorized keys"
    #ssh $server "ssh-copy-id -i ~/.ssh/id_rsa.pub \$SSH_CLIENT" #this might need some awk, as $SSH_CLIENT spits out clientip portnumber

    echo "Displaying server public key"
    ssh $server "cat ~/.ssh/id_rsa.pub"

    #Though, he did give me a good idea
    echo "Displaying keys authorized on $server (you can paste them in your authorized_keys file)"
    ssh $server "cat ~/.ssh/authorized_keys"

    #echo "Appending keys authorized on $server to your local authorized_keys"
    #ssh $server "cat ~/.ssh/authorized_keys" >> ~/.ssh/authorized_keys
done
echo "SSH keys schronized successfully!"