regex - 如何在 bash 脚本中使用正则表达式？

Question

我想使用正则表达式检查变量是否具有有效年份。阅读bash manual我知道我可以使用运算符 =~

查看下面的示例，我希望看到“不正常”，但我看到“正常”。我做错了什么？

i="test"
if [ $i=~"200[78]" ]
then
  echo "OK"
else
  echo "not OK"
fi

Answer 1

它在 3.1 和 3.2 之间发生了变化:

This is a terse description of the new features added to bash-3.2 since the release of bash-3.1.

Quoting the string argument to the [[ command's =~ operator now forces string matching, as with the other pattern-matching operators.

因此在不带引号的情况下使用它:

i="test"
if [[ $i =~ 200[78] ]] ; then
    echo "OK"
else
    echo "not OK"
fi