CODEWITHSUNDEEP
bashshell
Vincent Lee
Vincent Lee

Reputation: 5

Is there a way to do this in bash? echo $$((2-1))

I have a few strings in $1 to $#. I want to perform a simple arithmetic expression and echo out the value of $ based on the # of the expression.

eg. set file1 file2 file3 file4

I want to echo $2 (file2) but using an arithmetic expression "echo $$((3-1))", which I thought would resolve to $2 but bash just throws an error.

Upvotes: 0

Views: 124

Answers (2)

chepner
chepner

Reputation: 531758

Using the substring expansion operator:

$ set -- file1 file2 file3 file4
$ echo ${@:$((3-1)):1}
file2

Upvotes: 0

that other guy
that other guy

Reputation: 123550

Use variable indirection:

set -- foo bar baz
var=$((1+1))
echo "${!var}"

This will print the value of $2, i.e. "bar".

Upvotes: 3

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