Let’s look at another option, “-z”, used so far in Bash to check for the empty string. The code has been started with Bash support, and we have initialized a string variable “v” with the value “Hello” in it. Then, we started the “if-else” statement to check whether the ...
Afterdeclaring a string variable, use the-zoperator in anif statementto check whether a string is empty or not: MY_STRING="" if [ -z $MYSTRING ] then echo "String is empty" else echo "String is not empty" fi For more Shell scripting tips,check out or Bash/Shell scripting articles!
-n operator -n is one of the supported bash string comparison operators used for checking null strings in a bash script. When -n operator is used, it returns true for every case, but that’s if the string contains characters. On the other hand, if the string is empty, it won’t ret...
Check empty bash array with string comparison We are going to use two elements to check if bash array is empty or not. One is${#array[@]}and other is the-zoperator. Here, the${#array[@]}is used in Bash for array expansion, allowing you to access all elements of an array.Don't ...
No, the -z option can take a string literal, a variable, or an outcome of the pipeline or command. Use the -n Option Use the -n option to check if the specified variable is empty in Bash. Use -n Option 1 2 3 4 5 6 7 8 variable="" if [ -n "$variable" ]; then echo...
Run Bash Script MyScript.sh 1 2 3 ./MyScript.sh Output 1 2 3 No match found In this example, the substitution command is used with $() to capture the output of grep, and then the -z option of the test command is used to check if the resulting string is empty or not. He...
BashBites:Check Files Check a file exists 1 2 3 4 5 6 7 1. 2. 3. 4. 5. 6. 7. #!/bin/bashif [[ -e /tmp/adb.log ]]then echo "Exists"else echo "Not Exists"fi 1. Check Empty String 1 2 3 4 5 6 1. 2. 3.
# Check if file is empty if["$file_size"-gt"$size_threshold"] then echo"File exists and is not empty" else echo"File exists but is empty" fi else echo"File does not exist" fi In this bash script example, we first set the filename, the size_threshold variable and then check if ...
In this scenario, we usethe parameter expansionto remove everything that matches the “apple” substring. If the match is successful, then the result will be empty, and the exit status of the test[ -z … ]will be true. Finally, we can use thecasekeyword: ...
安装HAP时提示“code:9568344 error: install parse profile prop check error” 问题现象 在启动调试或运行应用/服务时,安装HAP出现错误……欲了解更多信息欢迎访问华为HarmonyOS开发者官网