Performing Shell expansions operations in simple isolated examples

shortcuts.sh

#!/bin/bash

# shell expansion -> ability to use shortcuts to manage ouputs

echo sh{ot,ort,oot} # print out a list
echo st{il, al}l

# getting the HOME directory
echo ~

export NETPATH=PATH:~
env | grep NEWPATH

export NEWPATH=$PATH:~/bin
env | grep NEWPATH

# pwd equivalent
echo ~+

# old pwd
echo ~-

# instead of
env | grep "HO*"
# you should
echo "${!HO*}"

# set a variable and print at the same time
echo "${VARNAME:=valuesomething}"
echo $VARNAME

# for expressions
echo  "$[ 2 * 2 ]"