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Vidar Holen edited this page Nov 3, 2022
·
2 revisions
In POSIX sh, $[..] in place of $((..)) is undefined.
Problematic code:
var=$[1 + 2]
Correct code:
var=$((1+2))
Rationale:
Your script uses a shell feature not supported by the shebang. Either rewrite the script to be portable, or change the shebang to explicitly require a shell like Bash. In this case, $[ .. ] can easily be replaced by the POSIX standard arithmetic expansion $(( .. )).
Exceptions:
None
Related resources:
Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!