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

#Originally made by Isaac Cook https://gist.github.com/icook/5400173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!"

#pinger.sh by Leif Messinger

#./pinger.sh [ADDRESS] to search

#./pinger.sh [ADDRESS] & to search in the background

#https://serverfault.com/a/42382
ping_cancelled=false # Keep track of whether the loop was cancelled, or succeeded
until ping -c1 "$1" >/dev/null 2>&1; do :; done & # The "&" backgrounds it
trap "kill $!; ping_cancelled=true" SIGINT
wait $! # Wait for the loop to exit, one way or another
trap - SIGINT # Remove the trap, now we're done with it
if [ "$ping_cancelled" == true ] #https://stackoverflow.com/a/21210966/10141528
then
	printf "The pinger for $1 just closed bro.\n"
else
	printf "$1 IS UP BROOO\a\n"
fi

#!/bin/bash

#getDependencies.sh by Leif Messinger
	grep -Po '#include\s*"\K.+(?=")' | while read -r line ; do
	echo -n " $line"
	./getDependencies.sh < $line
done

#!/bin/bash
#  RCLONE BACKUP SCRIPT (using ionice)
#  Type crontab -e and copy the line below without the #
#  0 0 * * * ionice -c 3 /home/owner/backup.sh >/dev/null 2>&1 
nowdate=$(date -u)

# OPTIONS
WEBHOOK="YOUR_DISCORD_WEBHOOK_LINK_HERE"
LOGFILE="/root/backup.log"
FROM="/path/where/you/backup/from"
TO="backblaze:BucketName/FolderName"
SERVERNAME="Server Name"

echo "$SERVERNAME started a backup - $nowdate" | tee -a $LOGFILE
curl --data "content=$SERVERNAME started a backup - $nowdate" $WEBHOOK | tee -a $LOGFILE && echo "" >> $LOGFILE

if pidof -o %PPID -x "backup.sh"
then
        echo "Failed backup attempt on $SERVERNAME - $nowdate (rclone already running)" | tee -a $LOGFILE
        curl --data "content=Failed backup attempt on $SERVERNAME - $nowdate (rclone already running)" $WEBHOOK | tee -a $LOGFILE
        exit 1
fi

rclone sync $FROM $TO -P --b2-hard-delete --stats 5s --progress | sed 's/Transferred:/\n\nTransferred:/' | tee -a $LOGFILE

enddate=$(date -u)
endtime=$(date +'%T')
echo "Completed backup on $SERVERNAME - $enddate" | tee -a $LOGFILE
curl -F "content=Completed backup on $SERVERNAME - $enddate" -F upload=@"$LOGFILE" $WEBHOOK | tee -a $LOGFILE

if [ -f $LOGFILE ]
then
        rm $LOGFILE
fi

#!/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 "$1" ]; then
        for arg; do
                recursive=$(if [[ -d $arg ]]; then printf " -r"; fi)
                printf "scp$recursive \"$(whoami)@$(hostname):"
                printf `readlink -f $arg`
                printf "\" .\n"
        done
else
		echo "scp \"$(whoami)@$(hostname):$PWD/*\" ."
fi


#-----------EDIT:

#On the UNT cell machines, you have to do this script instead

##!/bin/bash

#if [ -n "$1" ]; then

#        for arg; do

#                recursive=$(if [[ -d $arg ]]; then printf " -r"; fi)

#                printf "scp$recursive $(whoami)@$(hostname).eng.unt.edu:"

#                printf `readlink -f $arg`

#                printf " .\n"

#        done

#else

#        echo "scp $(whoami)@$(hostname).eng.unt.edu:$PWD/* ."

#fi