Numbers and Arithmetic in bash: Difference between revisions

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((i--))
((i--))
</pre>
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=Random Numbers=
{{Internal|Bash script that generates a random MAC address|Bash script that generates a random MAC address}}

Revision as of 19:35, 29 December 2018

Internal

How to Tell if a Variable has an Integer Value

v=10

if expr ${v} + 1 >/dev/null 2>&1; then
    #
    # the value contained by v is an integer
    #
else
    #
    # the value contained by v is NOT an integer
    #
fi

More about

expr

Floating Point Operations

Multiplication:

local operand1=10.1
local operand2=20.2

result=$(echo ${operand1} ${operand2} | awk '{printf "%5.1f\n",$1*$2}') || exit 1

Division:

local operand1=10.1
local operand2=20.2

result=$(echo ${operand1} ${operand2} | awk '{printf "%5.1f\n",$1/$2}') || exit 1

Increment an Integer

local i=0
((i++))

Decrement an Integer

local i=1
((i--))

Random Numbers

Bash script that generates a random MAC address