How to use Shell script if else statements
This article mainly introduces "how to use Shell script if else statements". In daily operation, I believe many people have doubts about how to use Shell script if else statements. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about "how to use Shell script if else statements". Next, please follow the editor to study!
Unlike Java, PHP and other languages, the process control of sh cannot be empty, such as:
The code is as follows:
You can't write this in sh/bash. If the else branch doesn't have a statement to execute, don't write the else, like this:
The code is as follows:
If condition
Then
Command1
Command2
...
CommandN
Fi
Of course, it can also be written as a line (for terminal command prompts), like this:
The code is as follows:
If test $[2: 3]-eq $[1: 5]; then echo 'The two numbers are equalizer; fi
The fi at the end is if, which is spelled upside down, and you'll encounter something similar later.
If else format
The code is as follows:
If condition
Then
Command1
Command2
...
CommandN
Else
Command
Fi
If else-if else format
The code is as follows:
If condition1
Then
Command1
Elif condition2
Command2
Else
CommandN
Fi
If else statements are often used in conjunction with the test command, as follows:
The code is as follows:
Num1=$ [2x3]
Num2=$ [1x 5]
If test $[num1]-eq $[num2]
Then
Echo 'The two numbers are equalizer'
Else
Echo 'The two numbers are not equalizer'
Fi
Output:
The two numbers are equal!
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