Bash, short for "Bourne Again SHell," is a powerful scripting language used in Unix-based operating systems. One of the fundamental constructs in Bash programming is the if statement. The if statement allows you to control the flow of your script based on specific conditions. In this article,...
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 equal) How to use the BASH_REMATCH variable with the Regular Expression Operator =~?
including if, else, and elif. Then we'll look at a few of the "primary" operators you can leverage in a conditional statement such as = for string equality, -eq for numeric equality, and -e to check if a file exists. After that, we'll use conditional statements...
比较bash中的两个字符串变量 bash if-statement 这段代码不断重复“他们是平等的”为什么? #!/bin/bash foo="hello" bar="h" if [[ "$foo"=="$bar" ]]; then echo "they are equal" else echo "they are not equal" fi 发布于 1 年前 ✅ 最佳回答: 条件的工作基于其中的元素数量,这个特定...
if [[ $USER = 'username' ]]; then echo "true" else echo "false" fi 1. 2. 3. 4. 5. not equal:!= numeric equality:-eq not equals:-ne is empty:-z if [[ 1 -eq 1 ]]; if [[ -z $USER ]]; 1. 2. 3. Elif if [[ -z $USER ]]; then ...
In this example, we have two variables, ‘a’ and ‘b’. The script checks if ‘a’ is equal to ‘b’. If it’s not, it moves on to the ‘elif’ statement to check if ‘a’ is greater than ‘b’. If neither condition is met, it executes the ‘else’ statement, which in ...
statement2 ... if(结束) 双分支语句 if 判断条件 then然后 statement 1 statement2 statement3 else否则 statement4 statement5 fi结束 上边的相信估计看不懂,,下边举一个例子: 显示一个用户的是否为系统用户 即ID为0 如果是则输出administrator 不是则 common ...
if [ $NUM1 -eq $NUM2 ]; then echo "Both Values are equal" else echo "Values are NOT equal" fi 1. 2. 3. 4. 5. 6. 7. 8. 9. #!/bin/bash # declare integers NUM1=2 NUM2=1 if [ $NUM1 -eq $NUM2 ]; then echo "Both Values are equal" ...
The condition in the IF statement was true, so only the firstechocommand was executed. Now let’s run the program with5as the first argument: bashsimpleelif.sh 5 ## 5 is a great number The first condition is false since 5 is not equal to 4, but then the next condition in the ELIF...
2. if [ 表达式 ] then 语句 else 语句 fi 3. if [ 表达式] then 语句 elif[ 表达式 ] then 语句 elif[ 表达式 ] then 语句 …… fi 例子: a=10 b=20 if [ $a == $b ] then echo "a is equal to b" else echo "a is not equal to b" ...