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"

#!/usr/bin/env bash


#Splits a command across a number of CELL machines

user=$(whoami)
if [[ -z $user ]]; then
	echo "whoami failed. Exiting..."
	exit 1
fi

command="$1"
if [[ -z $command ]]; then
	echo "Need to put in a command."
	exit 1
fi
shift

array=("$@")

let start=8
let stop=18

for ((i = $start; i <= $stop; i++)); do
	extraZero=$(if [[ "$i" -lt 10 ]]; then echo "0"; fi)
	domain="CELL${extraZero}${i}-CSE.ENG.UNT.EDU"
	let "index = i - start"
	echo ${#array[@]}
	if [[ ${#array[@]} != 0 ]] && [[ $index -ge ${#array[@]} ]]; then
		echo "$index > ${#array[@]}"
		break
	fi
	ssh -o StrictHostKeyChecking=accept-new "${user}@${domain}" -t "$command ${array[$index]}" &
done

#!/bin/bash

for branch in $(git branch | cut -c 3-); do
    read -p "Delete local branch $branch? (y/n) " -n 1 -r
    echo ""
    if [[ $REPLY =~ ^[Yy]$ ]]; then
        git branch -D $branch
    fi
done

#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

#Leif Messinger

#For when you want to search a lot of words in a file fast


#Arg 1 is the argument the list of words you want to search

#Arg 2 is the file you want to search


#-z means that it looks at the file as a whole, just treating newlines a characters.

#-r is regex. Needed for $, even tho the documentation says you don't need it. They are liars.

#First command replaces all . with \. and all - with \-

#Second command takes all newlines and replaces them with )|(

#Third command takes the trailing |( and deletes it

#Forth command puts a /( at the start

#Fith command puts /!d at the end. This tells it to not delete any lines that match the pattern.


#The second sed takes the output of the first sed as a command that searches any of the combined words

#-f - takes a command from the input
sed -z -r -e 's/\./\\\./g ; s/\-/\\\-/g' -e 's/\n/\)\|\(/g' -e 's/\|\($//' -e 'i/\(' -e 'a/!d' $1 | sed -r -f - $2

CLIENT_VPN_ID="cvpn-endpoint-xxxxxxxxxxxx"

for region in $(aws ec2 describe-regions --query "Regions[].RegionName" --output text); do
    echo "Searching in region: $region"
    aws ec2 describe-client-vpn-endpoints --region $region --query "ClientVpnEndpoints[?ClientVpnEndpointId=='$CLIENT_VPN_ID']" --output table
done