bash还能使用正则表达式，以前都没留意过，都是用外部程序 sed, grep来完成的

翻译于 2012-07-15 11:57:01 发布 · 620 阅读

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本文介绍如何在Bash中使用=~操作符进行正则表达式匹配，并通过实例演示了如何将正则表达式存储在变量中以避免shell解析错误。

http://wiki.bash-hackers.org/syntax/ccmd/conditional_expression

Regular Expression Matching

Using the operator =~, the left hand side operand is matched against the extended regular expression (ERE) on the right hand side.

This is consistent with matching against patterns: Every quoted part of the regular expression is taken literally, even if it contains regular expression special characters.

Best practise is to put the regular expression to match against into a variable. This is to avoid shell parsing errors on otherwise valid regular expressions.

REGEX="^[[:upper:]]{2}[[:lower:]]*$"

# Test 1
STRING=Hello
if [[ $STRING =~ $REGEX ]]; then
  echo "Match."
else
  echo "No match."
fi
# ==> "No match."