count.sh

#!/usr/bin/env bash
# Counting to 11 in 10 different ways.
n=1; echo -n "$n "
let "n = $n + 1"   # let "n = n + 1"  also works.
echo -n "$n "
 
: $((n = $n + 1))
#  ":" necessary because otherwise Bash attempts
#+ to interpret "$((n = $n + 1))" as a command.
echo -n "$n "
 
(( n = n + 1 ))
#  A simpler alternative to the method above.
#  Thanks, David Lombard, for pointing this out.
echo -n "$n "
 
n=$(($n + 1))
echo -n "$n "
 
: $[ n = $n + 1 ]
#  ":" necessary because otherwise Bash attempts
#+ to interpret "$[ n = $n + 1 ]" as a command.
#  Works even if "n" was initialized as a string.
echo -n "$n "
 
n=$[ $n + 1 ]
#  Works even if "n" was initialized as a string.
#* Avoid this type of construct, since it is obsolete and nonportable.
#  Thanks, Stephane Chazelas.
echo -n "$n "
 
# Now for C-style increment operators.
# Thanks, Frank Wang, for pointing this out.

let "n++"          # let "++n"  also works.
echo -n "$n "
 
(( n++ ))          # (( ++n )  also works.
echo -n "$n "
 
: $(( n++ ))       # : $(( ++n )) also works.
echo -n "$n "
 
: $[ n++ ]         # : $[ ++n ]] also works
echo -n "$n "

# each array element
fruits[0]=Apple
fruits[1]="Desert fig"
fruits[2]=Plum

#for i in "${fruits[*]}" # all element for one element
#for i in ${fruits[*]}   # for each element with space identity
for i in "${fruits[@]}" # for each element
do
    echo $i;
done

# Adding elements into an array
fruits=(Orange "${fruits[@]}" Banana Cherry)