aprell/gotcha.sh

Created June 5, 2022 14:43

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Be wary of arithmetic expressions when using `set -e`

Raw

	#!/usr/bin/env bash

	set -e

	i=0

	while [ $i -lt 3 ]; do
	r=$((RANDOM % 10))
	if [ $r -lt 3 ]; then
	((i++))
	fi
	done

	echo "Done: i = $i"

Author

aprell commented Jun 5, 2022 •

edited

$ ./gotcha.sh
$ # Nothing

Use either ((++i)) or i=$((i + 1)) in this case. The reason:

$ i=0; ((i++)); echo $?
1
$ i=0; ((++i)); echo $?
0

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