Bash: If Bashscripts are used on the Linux operating system. These scripts carry out one or more commands. They are very powerful, however, as they support a number of features of programing languages. One of the major key words supported by Bash is the conditional statement, orifstatement;...
For this, we need to utilize the not operator “!” with the “if” statement in the bash script. Let’s discuss the use of the “if-not” operator in Bash programming with the help of some examples. Get started with the new Bash file creation while using the terminal shell of the ...
In bash script, if you wish to apply multiple conditions using if statement then use ‘ if elif else’. In this type of conditional statement, if the first condition is met then code below it will be executed otherwise next if condition will checked and if it is not matched then commands...
[ s1 ] (true if s1 is not empty, else false) [ -n s1 ] (true if s1 has a length greater then 0, else false) [ -z s2 ] (true if s2 has a length of 0, otherwise false) Example Script number.sh #!/bin/bash echo -n “Enter a number 1 < x < 10: " read num if [ ...
if [ $age -gt 18 ] && [ "$grade" == "A" ] then echo "Congratulations! You are eligible for a scholarship." else echo "Sorry, you are not eligible for a scholarship." fi Nested If statement In your bash script, you have the flexibility to incorporate multiple if statements as need...
Example 7: If Else Statement in Bash Scripting We will now demonstrate theELSEcondition. TheELSEcondition is used in the case where theIFcondition or all theELIFconditions do not exist then theELSEcondition will be used and the code in theELSEcondition will be executed. Let’s add an example...
Check to see if a variable is empty or not Create a new bash file, named, and enter the script below. The script above stores the first command-line argument in a variable and then tests the argument in the next statement. This script will print the first argument because it is not em...
A Shell script usually needs to test if a command succeeds or a condition is met. In Bash, this test can be done with a Bash if statement. As with any other programming language, Bash comes with conditional expressions that allow you to test for conditions and alter the control flow if ...
<statement_to_execute_if_condition_is_false> fi 例如,要检查用户是否有资格投票: #!/bin/bash echo "Please enter your age:" read age if [ "$age" -ge 18 ]; then echo "Congratulations! You are eligible to vote." else echo "Sorry, you are not eligible to vote yet." ...
从你的代码中我可以看出，这（使用bash 4.3或更高版本来测试-v的数组索引存在性）似乎是你想要做的...