```bash if [[ ]]; then fi Exp: if[[$USER='username']];thenecho"true"elseecho"false"fi not equal:!= numeric equality:-eq not equals:-ne is empty:-z if[[1-eq1]];if[[-z$USER]]; Elif if[[-z$USER]];thenecho"user is
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 equal) How to use the BASH_REMATCH variable with...
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,...
Basic conditional block: ```bash if [[ ]]; then fi 1. 2. 3. 4. 5. 6. Exp: 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 $...
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 ...
整数比较: -eq 测试两个整数是否相等,相等为真,不等为假。 equal -ne 测试两个整数是否不相等,不相等为真,否则为假 not equal -gt 测试一个整数是否大于另一个,大于为真,否则为假。 greater than -lt 测试一个速度是否小于另一个,小于为真,否则为假。 less than ...
if [ $x -gt $y ] then echo X is greater than Y elif [ $x -lt $y ] then echo X is less than Y elif [ $x -eq $y ] then echo X is equal to Y fi 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Output: ...
你所看到的是if语句的第一行,它在检查变量的值是否真的等于12。如果是的话,语句就会停止,并发出numberTwelve is equal to 12的回显,然后在fi之后继续执行你的脚本。如果变量大于12的话,就会执行elif语句,并在fi之后继续执行。当你使用if或if/elif语句时,它是自上而下工作的。当第一条语句是匹配的时候,它会停...
bashsimpleif.sh 77 ## Start program ## End program We provided the argument77, however 77 is not equal to 4, therefore the code within the IF statement was once again skipped. Finally let’s provide4as an argument: bashsimpleif.sh 4 ...
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" fi 另外:if ... else 语句也可以写成一行,以命令的方式来运行,像这样: ...