Bash Increment Counter Integer Variable

To increment a counter in bash, use any of the following:

#!/bin/bash

set -x

x=1
echo $x

(( x++ ))
echo $x

(( x += 1 ))
echo $x

let x++
echo $x

x=$(echo "$x + 1" | bc)
echo $x

+ x=1
+ echo 1
1
+ ((  x++  ))
+ echo 2
2
+ ((  x += 1  ))
+ echo 3
3
+ let x++
+ echo 4
4
++ echo '4 + 1'
++ bc
+ x=5
+ echo 5
5

kw: addition, add, subtraction, subtract, mathematics, math