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"

#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

#!/bin/bash

git status

echo "Do you want to add all changed files?"
select yn in "Yes" "No"; do
        case $yn in
                Yes ) break;;
                No ) exit 1;;
        esac
done

git add -u

git status

echo "Does this look right?"
select yn in "Yes" "No"; do
        case $yn in
                Yes ) break;;
                No ) exit 2;;
        esac
done

git commit

echo "Do you want to push?"
select yn in "Yes" "No"; do
        case $yn in
                Yes ) break;;
                No ) exit 2;;
        esac
done

git push

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

#!/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

# Turns 4 spaces into tabs.

# Mostly stolen from AI

# Define the directory to process
DIRECTORY=$1
TabCount=${2:-'4'}    #Defaults to 4


# Check if directory is specified
if [ -z "$DIRECTORY" ]; then
    echo "Error: Directory not specified."
    exit 1
fi


# Check if directory exists
if [ ! -d "$DIRECTORY" ]; then
    echo "Error: Directory does not exist."
    exit 1
fi


# Find all files in directory and subdirectories
FILES=$(find "$DIRECTORY" -type f)


# Loop through each file and unexpand it
for FILE in $FILES; do
	unexpand -t "$TabCount" "$FILE" > "$FILE.tmp"
	mv "$FILE.tmp" "$FILE"
done

echo "Done!"