#!/bin/bash

say_hello ()
{
  echo "Hello!"
}

get_date()
{
  local dt=`date`
  echo $dt
}

count_files ()
{
  local count=`ls -l | wc -l`
  echo $count
}

print3()
{
  echo "Printing: $1 $2 $3"
}

validate3()
{
  echo "params: $#"
  if [[ -x $1 ]]; then
    true;
  else
    false;
  fi
}


multiply()
{
  local product=$[$1*$2]
  echo $product
}



say_hello
dt=$(get_date)
echo $dt
print3 one two three

num_files=$(count_files)
echo $num_files
echo "The number of files is $(count_files)"

total=$(multiply 3 5)
echo $total

value=3
if [[ $value -eq 3 ]]; then
  echo "The value is 3"
else
  echo "The value is NOT 3"
fi

string1="Hello"
string2="hello"
if [[ $string1 == $string2 ]]; then
  echo "Same strings"
else
  echo "Different strings"
fi

filename="foo.txt"
echo -n "$filename "
if [[ -e $filename ]]; then
  echo "exists"
else
  echo "does not exist"
fi

filename="a.exe"
echo -n "$filename "
if validate3 $filename; then
  echo "is executable"
else
  echo "is not executable"
fi
 
for f in *; do 
  #if validate2 $f; then
    echo $f
  #fi
done

for i in "hello 1 * 2 goodbye" 
do
  echo "Looping ... i is set to $i"
done

echo $@
echo $#


while [[ "$#" -gt "0" ]]
do
  echo "\$1 is $1"
  shift
done 

file_exists()
{
  if [ -e $1 ] ; then
    return 0
  else
    return 1
  fi
}

filename="foo.txt"
if file_exists $filename; then
  echo "$filename exists"
else
  echo "$filename does not exist"
fi

filename="a.exe"
res=$(validate3 $filename)
echo "$res"

filename="a.exe"
echo -n "$filename "
if validate3 $filename; then
  echo "is executable"
else
  echo "is not executable"
fi


for (( c = 1; c <= 5; c++ ))
do
  echo "Welcome $c times..."
done


for a in 1 2 3 4 5
do
  echo -n "$a "
done  
echo
NUMS="1 2 3 4 5"
for a in $NUMS
do
  echo -n "$a "
done  
echo
for a in {1..5}
do
  echo -n "$a "
done  
echo

for (( a = 1; a <= 5; a++ ))
do
  echo -n "$a "
done

echo

for a in *.cpp
do
  echo "$a "
done  

generate_list()
{
  echo "one two three"
}

for word in $(generate_list)  # Let "word" grab output of function.
do
  echo "$word"
done


t=0
condition()
{
  ((t++))
  #echo "in condition"
  if [ $t -lt 5 ]
  then
    return 0  # true ((1))
  else
    return 1  # false ((0))
  fi
}

one=1
two=2

sum=$one+$two
echo "$sum"

let a="$one + $two"
echo "$a"

MY_TEST_FLAG=0 
if [[ $MY_TEST_FLAG == 1 ]]; then
  echo "MY_TEST_FLAG is ON"
else
  echo "MY_TEST_FLAG is OFF"
fi

while condition
do
  echo "Still going: t = $t"
done

something()
{
  ((0))
}

if something
then
  echo "Expression is true"
else
  echo "Expression is false"
fi

a=1+2
echo $a


let a=1+2
echo $a

#let a = 1 + 2
echo $a 


let a="1 + 2"
echo $a

echo 
echo 

a=1

((a=$a+2))         
echo $a

((a = a + 2))      
echo $a

((a += 2))         
echo $a

echo

i=0
while [ $i -lt 4 ]
do
  i=$(($i + 1))
  echo -n "$i "
done

echo 

i=0
while [ $i -lt 4 ]
do
  i=$[$i + 1]
  echo -n "$i "
done

echo
echo $(pwd)

print3 apple "banana cherry" dog

for a in *
do
  if [ -d "$a" ]
  then
    echo "$a "
  fi
done


for i in *
do
  echo "(*) "${i}
done

echo "*********"
for i in *
do
  if [ -d $i ]
  then
    echo "[d] "$i
  else
    echo "[f] "$i
  fi
done

echo "*********"
COUNT=0
for i in *
do
  if [ ! -d $i ]
  then
    # same as ((COUNT++))
    let COUNT=COUNT+1
    echo "("${COUNT}") "${i}
  fi
done
echo $COUNT

fruits=()
for i in apple banana cherry
do
  fruits+=($i)
done

for j in ${fruits[@]}
do
  echo $j
done

echo
echo "Bash version ${BASH_VERSION}..."