calculate the bonus amount based on the return value of the “if” condition. Three “if” conditions with a logical AND operator and two conditions are used in the script. If none of the “if” conditions returns true, the bonus is 0. ...
6 elif [ condition2 ] 7 # Same as else if 8 then 9 command4 10 command5 11 else 12 default-command 13 fi使用if test condition-true这种形式和if[condition-true]这种形式是等价的.向我们前边所说的"["是test的标记.并且以"]"结束.在if/test中并不应该这么严厉,但是新版本的Bash需要它.注意:tes...
条件语句, if/then/elif 在某些情况下,我们需要做条件判断。比如判断字符串长度是否为0?判断文件foo是否存在?它是一个链接文件还是实际文件?首先,我们需要if命令来执行检查。语法如下: if condition then statement1 statement2 ... fi 当指定条件不满足时,可以通过else来指定其他执行动作。 if condition then state...
因为if condition,如果条件为真,就会进入if块区域内执行命令。 如果你是对$?结果很执着的读者,可以去看朱双印的博客原文。 场景一:判断变量是否为空 假如有变量 如上表所示,变量值非空时 condition 为真。使用上述方法判断变量值是否为空时,[ ] 与 [[ ]] 没有区别。 我们可以使用”!”进行取反,使得变量值...
if[[$USER_INPUT-lt10||$USER_INPUT-ge100]];then echo"Your entry is NOT two digits" fi In this example the logicalORoperator combines two conditions and only one of them or both can be true for the condition to be overall true and the code to execute. We also demonstrate the-geoperat...
7. Bash 中的 if ## FORMAT if [ condition ]; then cmd elif [ condition ]; then cmd else cmd fi ## EXAMPLE if [ -e file1 ] # file1 exists if [ -f file1 ] # file1 exists and is a regular file if [ -s file1 ] # file1 exists and size > 0 if [ -L file1 ] # fil...
If you use the >> operator instead, the output from ls is appended to what's already in listing.txt:Bash Copy ls >> listing.txt The piping operator is powerful (and often used). It redirects the output of the first command to the input of the second command. Let's say you use ...
#ifcondition (equal to) isfalse if[10-eq9]; then echo"10 is not equal to 9" fi Output Example 4 In this example, we will define how to use AND operator to include multiple conditions in the if expression: #!/bin/bash # TRUE && TRUE ...
How to check if a command succeeds or failed? How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not ...
If found, thecasestatement compares theextensionand outputs the file type. 3. Save the file and close Vi: :wq 4. Make the script executable: chmod +x filelist.sh 5. Execute the script: ./filelist.sh The script finds and prints the file type of each file in the current directory. Expa...