-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. -...
Check if String Starts with Another String in Bash Read more → 6. Using sed with grep Command The sed (Stream Editor) is a powerful and versatile text processing tool that performs text transformations on an input stream (a file or input from a pipeline). Here, we will use sed for ...
Here is another option, “-n”, to check whether the specified string is empty or not. It works on the rule of checking the length of a string by counting the string characters in it. If the length of a particular string turns out to be other than zero, it will return “true”; o...
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...
How to Check if String Contains a Substring in Bash So, you have a long string and you want to check of this string contains a substring in your bash script. There are more than one way to check for substrings in bash shell. I'll show some simple examples first, followed by a cool...
使用bash遍历命令获取目录中的文件数可以通过以下步骤实现: 1. 打开终端或命令行界面。 2. 使用cd命令切换到目标目录,例如:cd /path/to/directory。 3. 使用以下命令获...
[ STRING1 > STRING2 ] 如果 “STRING1” sorts after “STRING2” lexicographically in the current locale则为真。 [ ARG1 OP ARG2 ] “OP” is one of -eq, -ne, -lt, -le, -gt or -ge. These arithmetic binary operators return true if “ARG1” is equal to, not equal to, less than...
In Bash scripting, it's often necessary to check if a string contains a specific substring. This can be useful for validating user input, processing text data, or executing certain actions based on the presence or absence of a certain pattern. The process of checking if a string contains a...
The ‘-eq’ operator is used to check if the exit status is equal to zero or not, which indicates that the command or script has completed successfully. If the exit status is not equal to zero, the ‘else’ block is executed, which prints a message indicating that the command has faile...
In the above example, we initialized the file1 and file2 variables with the two different text file locations. Then, we used the if statement with the cmp command to check if the content of $file1 and $file2 was the same. If it was the same, then the echo from the if block was ...