基本格式:if 条件1 then 命令1 else 命令3 if 扩充版的格式:if 条件1 then 命令1 elif 条件2 then 命令2fi else 命令3 fi 判断的内容: 例3:判断文件是否存在,若存在,则输入“ok”;若不存在,则输入“file not exist”。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 if[-f aaa.
在bash资源中,not_if是Chef中的一个条件语句,用于判断是否需要执行某个资源。它的作用是在执行资源之前检查一个条件,如果条件为真,则不执行该资源。 not_if的语法如下: ``` not...
Check if a File Does not Exist Testing for a file returns0(true) if the file exists and1(false) if it does not exist. For some operations, you may want to reverse the logic. It is helpful to write a script to create a particular file only if it doesn’t already exist. To do so...
Usage: mkdir [OPTION]... DIRECTORY... Create the DIRECTORY(ies), if they do not already exist. Mandatory arguments to long options are mandatory for short options too. -m, --mode=MODE set file mode (as in chmod), not a=rwx - umask -p, --parents no error if existing, make parent...
Usage: mkdir [OPTION]... DIRECTORY... Create the DIRECTORY(ies), if they do not already exist. Mandatory arguments to long options are mandatory for short options too. -m, --mode=MODE set file mode (as in chmod), not a=rwx - umask -p, --parents no error if existing, make parent...
找出一组数据中的最大数,这组数据用数组保存。 生成一个属组: 1、数组元素个数为1-39 read 2、数组元素不能相同 3、显示此属组各元素的值 trap: 在脚本中捕捉信号,并且可以实现特定处理 1: SIGHUP: 让一个进程不用重启,就可以重读其配置文件,并让新的配置信息生效; ...
/bin/bashFILE=$1 if [ -f $FILE ]; then echo "File $FILE exists." else echo "File $FILE does not exist." fi我如何只检查文件是否不存在?解决方案1:一个优秀的自由职业者,应该有对需求敏感和精准需求捕获的能力,而huntsbot.com centos提示bash命令找不到...
if [[ - f <file 1> ]] && [[-f <file> ]] then echo "file exists!" fi. Easy! Make sure to remember the “-f” command and file name you’re looking for. Check if a File Does Not Exist The next one you’ll need to learn is to check if a file exists no more. The comm...
create="-create" delete="-delete" # function code addUser() { userName=$1 ifid-u$userName>/dev/null 2>&1;then data="Attempted to add an existing user:$userName" echo$data echo$data>>$logStorageFile else password=$(openssl rand -base64 6) ...
Example 3: File Check #!/bin/bash file_path="/path/to/file.txt" if [ -f "$file_path" ] then echo "File exists." else echo "File does not exist." fi Compound Condition You can combine multiple conditions using logical operators like && (AND) and || (OR). Here’s an example:...