str="Hello World" if [[ "$str" == *"Hello"* ]]; then echo "String contains 'Hello'" else echo "String does not contain 'Hello'" fi 这些方法可以帮助你在Bash中正确比较变量和字符串。请注意,变量在比较时需要使用双引号括起来,以避免由于特殊字符引起的错误。 相关
Bash是一种常用的Unix shell和脚本语言,用于在Linux和其他类Unix系统上进行命令行操作和脚本编写。在Bash中,if条件语句用于根据条件的真假执行不同的代码块。 当使用if条件在比...
The return value is 0 if the string matches the pattern, and 1 otherwise. If the regular expression is syntactically incorrect, the conditional expression's return value is 2. Any part of the pattern may be quoted to force the quoted portion to be matched as a string. 即,使用=~操作符时...
echo"String /"string1/"is not null."elseecho"String /"string1/"is null"fi #结果显示string1为非空,错误if[ -n"$string1"] #string1仍然未被初始化 then echo"String /"string1/"is not null"elseecho"String /"string1/"is null"fi #结果显示string1为空,结果正确if[ $string1 ] #string1...
var="$(cut -d' ' -f 4 <<< $u)" echo"${var}" 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 想了解更多请阅读 bash 的 man 页: 复制 manbash mancut 1. 2. 另请参见:Bash String Comparison: Find Out IF a Variable Contains a Substring...
$ array=("something to search for" "a string" "test2000")$ containsElement "a string" "${...
if echo "$VAR" | grep -q txt # if [[ $VAR = *txt* ]] then echo "$VAR contains the substring sequence \"txt\"" fi echo命令可以与命令替换组合起来, 这样可以用来设置一个变量. a=`echo "HELLO" | tr A-Z a-z` 小心echo `command`将会删除任何由command所产生的换行符.$IFS (内部域分...
-n is one of the supported bash string comparison operators used for checking null strings in a bash script. When -n operator is used, it returns true for every case, but that’s if the string contains characters. On the other hand, if the string is empty, it won’t return true. ...
因此,你需要一组更复杂的测试代码 — 为了测试所有的情况,使用if-elif-else结构中的elif语句: [student@studentvm1 testdir]$ File="TestFile1" ; if [ -s $File ] ; then echo "$File exists and contains data." ; fi [student@studentvm1 testdir]$ ...
How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with the Regular Expression Operator =~?