The Bash if statement is a fundamental construct that allows you to control the flow of your scripts based on specific conditions. By leveraging conditionals, such as numeric and string comparisons, and file and directory checks, you can create dynamic and responsive scripts. Additionally, nesting ...
-afile:file 存在 -dfile:file存在并是一个目录 -efile:file 存在,同- a -ffile:file 存在并且是一个常规的文件(不是目录或者其他特殊类型文件) -rfile:有读的权限 -sfile:文件存在且不为空 -wfile:有写的权限 -xfile:有执行的权限,或者对于目录有search的权限 -Nfile:在上次读取后,文件有改动 -Ofile...
bash shell if-statement while-loop m3u 我正在编写一个脚本来解析m3u文件。目标是检索变量标记和url。我用这个文件做了测试。 #!/bin/bash echo "name,tvg-id,tvg-name,tvg-country,group-title,languages,url" while IFS= read -r line; do tags_detect="$(echo "$line" | grep -Eo '^#EXTINF:')...
if/else是通过判断选择执行或者执行部分代码,可以根据变量、文件名、命令是否执行成功等很多条件进行判断,他的格式如下:if condition then statements [elif condition then statements. ..] [else statements ] fi和C程序不一样,bash的判断不是通过boolean,而是通过statement,也就是执行命令后的最终状态(exit status)...
11. Bash File Testing #!/bin/bash file="./file" if [ -e $file ]; then echo "File exists" else echo "File does not exists" fi 1. 2. 3. 4. 5. 6. 7. Similarly for example we can use while loop to check if file does not exists. This script will sleep until file does exi...
Why you should not use the || and && operators instead of a Bash If Statement? Detailed Examples & FAQ How to check if a variable exists or is “null”? How to check if a file exists? How to check if a directory exists? How to check if a command succeeds or failed? How to do...
-x file 测试文件对当前用户是都可执行 -z 是否为空 为空则为真 -a 是否不空 五、if语法 if 判断条件 0为真 其他都为假 单分支if语句 if 判断条件;then statement1 statement2 ... fi 双分支的if语句: if 判断条件;then statement1 statement
'Else if'in bash scripting, often written as'elif', is used to check multiple conditions in your code. It is used with the syntax,if [firstStatement]; then... elif [secondCondition]; then... else. It’s a powerful tool that allows your scripts to make decisions based on various scen...
File/usr/bin/boot.ini exists 请参阅之前的文章以了解各种bash if 语句类型。 Bash 示例 2. 比较数字 下面的脚本从用户那里读取两个整数,并检查这两个数字是否相等或大于或小于彼此。 $ cat numbers.sh #!/bin/bash echo"Please enter first number"read first ...
执行case 尝试匹配的 表达式 与子句之一。它通过依次查看每个子句来尝试找到匹配的模式来做到这一点。子句中的模式是字符串，但是——与直觉相反——这并不意味着我们不能使用数值作为表达式。一般情况 case语句的一般形式是这样的：case expression in pattern-1) statement ;; pattern-2) statement...