Simple bash stuff

Hello World:
#!/bin/bash
echo Hello World!

Shebang:
#!/usr/bin/python3
print("I'm beeing run in python3")

Simple Backup:
#!/bin/bash
tar -cZf /var/backup.tgz /home/linux

Variables:
#!/bin/bash
variable="Inhalt"
echo #variable

If/Else:
#!/bin/bash
variable="Inhalt"
if [ $variable == "Inhalt" ]
then
    echo true
else
    echo false
fi

For-Loop:
#!/bin/bash
for i in $(seq 1 10)
do
    echo $i
done

For item in x:
#!/bin/bash
for item in `ls`
do
    echo item: $item
done

While:
#!/bin/bash
COUNTER=0
while [ $COUNTER -lt 10 ]
do
    echo $COUNTER
    let COUNTER=COUNTER+1
done

Until:
#!/bin/bash
COUNTER=20
until [ counter -lt 10 ]
do
    echo $COUNTER
    let COUNTER-=1
done

Funktion:
#!/bin/bash
function hello{
    echo Hello!
}
hello
exit

Funktion und Parameter:
#!/bin/bash
function e{
    echo $1
}
e hello
e hello world
e "Hello World!"

Interface:
#!/bin/bash
OPTIONS="Hello Done"
select opt in $OPTIONS
do
    if [ "$opt" = "Quit" ]
    then
        echo done
        exit
    elif [ "$opt" = "Hello" ]
    then
        echo Hello World!
    else
        clear
        echo bad option
    fi
done

Debug:
#!/bin/bash -x