= operators are used, the string to the right of the operator is considered a pattern and matched according to the rules described below under Pattern Matching. The return value is 0 if the string matches or does not match the pattern, respectively, and 1 otherwise. Any part of the pattern...
the string matching the entire regular expression. The element of BASH_REMATCH with index n is the por- tion of the string matching the nth parenthesized subexpression. 在Bash中二元操作符 =~ 进行扩展的正则表达式匹配。如果匹配,返回值为0,否则1,如果正则表达式错误,返回2。如果shell选项nocasematch没...
string1 == string2如果所给的两个字符串相等,返回 true,否则返回 false string1 != string2如果所给的两个字符串不相等,返回 true,否则返回 false string1 < string2如果string1字符串在词典上的顺序早于string2字符串,返回 true,否则返回 false string1 > string2如果string1字符串在词典上的顺序晚于string2...
操作符时,操作符右边的字符串被认为是一个模式,根 据下面 Pattern Matching(模式匹配) 章节中的规则进行匹配。如果匹配 则返回值是 0,否则返回 1。模式的任何部分可以被引用,强制使它作为 一个字符串而被匹配。 表达式可以用下列操作符结合起来。根据优先级的降序列出如下: ( expression ) 返回表达式 expression ...
This expansion modifies the case of alphabetic characters in parameter. The pattern is expanded to produce a pattern just as in pathname expansion. The ^ operator converts lowercase letters matching pattern to uppercase; the , operator converts matching uppercase letters to lowercase. ...
${1%%"$2"*}表示将将子串匹配后的所以字符全部删除,保留之前未匹配部分。有兴趣的伙伴可以利用man bash,查看“${parameter%%word}”的解释(“Remove matching suffix pattern”)。(感受下“A="hello"; echo "${A%%ll*}"”这条命令) 然后返回剩余部分的字符串的长度,这样变相知道了整个子串的偏移位置 ...
3. Pattern Matching and Substitution 3.1. Length We can access the length of a string using the hash (#) operator inside parameter expansion before the variable name: $ NAME=Baeldung $ echo ${#NAME} 8 3.2. Substrings We can extract a substring using the colon (:) operator inside the pa...
The next type of string operator is used to match portions of a variable’s string value against patterns. Patterns, as we saw in Chapter 1, are strings that can contain wildcard characters (*, ?, and [] for character sets and ranges). Table 4-2 lists bash’s pattern-matching ...
Use the correct operators for numerical and string comparisons. Indent your code properly to make it more readable. Test your scripts thoroughly to catch any errors. Use ‘case’ statements for pattern matching instead of long ‘elif’ chains. ...
在Bash 脚本中,检查变量是否包含特定的文本字符串是一个常见的任务。以下是一些基础概念和相关方法: 基础概念 变量:在 Bash 中,变量用于存储数据。 字符串比较:用于检查一个字符串是否包含另一个字符串。 相关优势 简洁性:Bash 提供了内置的字符串操作功能,使得代码更加简洁。