Checking if a string is NULL or EMPTY is very common requirement in Powershell script. If we don’t do that we will end up with run time errors if we try to perform some operation on that string variable which is empty or null. So the question now is, how to check it? Well, belo...
Afterdeclaring a string variable, use the-zoperator in anif statementto check whether a string is empty or not: MY_STRING="" if [ -z $MYSTRING ] then echo "String is empty" else echo "String is not empty" fi For more Shell scripting tips,check out or Bash/Shell scripting articles!
Use the strlen() Function to Check if String Is Empty in C++The strlen() function is part of the C string library and can be utilized to retrieve the string’s size in bytes. This method could be more flexible for both string and char* type strings that may come up in the codebase...
A shell script (isEmpty.sh) example to check if a file is empty or not. [code language="shell"] #!/bin/sh f='afile.txt' hasData () { echo "$f has data." ls -l $f cat $f } noData() { echo "$f is empty." ls -l $f } if [[ -s $f ]] then hasData else no...
$string="Hello World" The following example checks if a$stringvariable is null or not in PowerShell. It returns the first statement if the variable is not null or empty and the second statement if the variable is null or empty. if($string) {Write-Host"The variable is not null."}else...
Give a directory path and check if it contains any files or not. [code language="shell"] #!/bin/sh DIR='/a/path/to/a/directory/' if [ "$(ls -A $DIR)" ]; then echo "$DIR is not empty" else echo "$DIR is empty" fi [/code]
hdc shell命令是否支持schema uri模拟跳转 是否可以通过ApplicationContext启动UIAbility 使用hdc命令安装release HAP包到设备时上报“INSTALL_FAILED_APP_SOURCE_NOT_TRUSTED”错误 如何查询应用包的名称、供应商、版本号、版本文本、安装时间、更新时间描述信息 如何安装打包出来的App包(通过什么命令安装) 如何判断应...
-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. ...
-z –this test parameter returns true if the output string is empty and false if not Above, we utilize the if statement and the echo command to print whether the projects directory is empty. Also, we can count the number of items: $ if [ "$(ls -A projects | wc -l)" -eq 0 ]...
c. if all checks for each position pass, return true. Both the runtime and space complexity is O(N). classSolution {publicbooleanisTransformable(String s, String t) {intn =s.length(); List<Integer>[] sIdx =newList[10];for(inti = 0; i < 10; i++) { ...