How can I increment a value in a bash script array by 1?
Try this
myArr[3]=7
(( myArr[3]++ ))
echo ${myArr[3]}
# output
8
The (( .... ))
can perform bash/ksh's math operations, and the variables referenced inside, don't need to be passed out as in your example, you're probably thinking of a similar construct var=$(( ... MathStuff ...)) OR var=$( ... stringStuff ... )
(note the '$' before the opening paren).
Also note that inside (( ... ))
you don't need to use the leading '$' for any math variables like $pct or $counter. If you're using arguments to the script or a function like $1, $2, ... $N, THEN you need to use the $, so the value of $1 is used, instead of just '1'. Thanks to @ChrisDown for the reminder!
I hope this helps.
Admin
Updated on June 14, 2022Comments
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Admin almost 2 years
I'm trying to increment a value in an array by 1 using the following code, however I'm having some problems with it. Please can someone help me out?
myArray[$position]=((${myArray[$position]}++))
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Chris Down over 12 yearsNot true, there are some times where you will have to refer to them with a leading
$
to force the context ($1
,$2
...$N
). -
shellter over 12 yearsGreat, that would certainly affect someones results. I'll update when I get back. Thanks for the improvement!
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l0b0 about 11 years
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l0b0 about 11 yearsYou can also use
let myArr[3]++
.