bash101.sh

echo "Hello World"
echo "Hello\nWorld"


echo "\nLoad another file into context"
. load_vars

echo "Loaded \$VAR from . load_vars and its value is: $VAR"
echo "Script is also environmentally conscious: \$HOME = ${HOME}"

# Command line arguments
echo "\nArguments are context aware"
echo $1, $2, $4, $5
echo $@
echo ${@:2}
echo ${@:2:1}
read;clear

#############################################
# User entered content
printf "Enter a value: "
read value
echo "You entered: $value"


#############################################
# Variables are context aware
echo "\nFunctions and the local variables who love them"

someVar=5
echo "someVar = $someVar"
function printVar() {
  local someVar=10
  echo "someVar = $someVar"
}
printVar
echo "someVar = $someVar"
read;clear

###############################################

echo "\nFunctions and ... it's like Javascript all over again"
anotherVar="Hello"
echo "anotherVar = $anotherVar"
function changeVar() {
  anotherVar=Hola
}
changeVar
echo "anotherVar = $anotherVar"

read;clear
###############################################
# Passing arguments

function dejaVu() {
  echo "\nArguments are context aware"
  echo $1, $2, $4, $5
  echo $@
  echo ${@:2}
  echo ${@:2:1}
}
dejaVu arg1 4000 ${@:2} foo

read;clear
###############################################
# Returning values

function add() {
  # return $1 + $2  WRONG!
  #echo $1+$2  # prints 2000+17
  echo $(($1+$2))
}
add 2000 17
sum=$(add 2000 17)
echo $sum

read;clear

###############################################
# Returning values
echo "\n\nIt's bash!"
function ls_cwd() {
  ls -l | head -n 5 | tail -n 1 
}
ls_cwd

# STDIN, STDOUT, STDERR
echo "\n\nStreams all the way down"
echo $(add 2000 17) | sed -e 's/17/99/g'

out=$(foo bar baz 2>&1 > /dev/null) 
echo "\$out = *********$out***********"

echo "\n\nAll you need now are loops, conditions, case statements and you are ready to
rock and roll"