How to use the Shell script test command
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The test command in Shell is used to check whether a condition is true, and it can be tested in terms of values, characters, and files.
Numerical test
The parameter states that-eq equals to true-ne is not equal to true-gt greater than or equal to true-ge greater than or equal to true-lt less than or equal to true-le less than or equal to true
For example:
The code is as follows:
Num1=100
Num2=100
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!
String test
Parameter description = equal to true! = unequal is true-z string length false is true-n string length is true
For example:
The code is as follows:
Num1=100
Num2=100
If test num1=num2
Then
Echo 'The two strings are equalizer'
Else
Echo 'The two strings are not equalizer'
Fi
Output:
The two strings are equal!
File testing
Parameter description-e filename if the file exists, true-r filename if the file exists and readable, true-w filename if the file exists and writable, true-x filename if the file exists and executable, true-s filename if the file exists and at least one character, true-d filename if the file exists and is a directory, true-f filename if the file is saved True-c file name if the file exists and is a character-type special file, true-b file name if the file exists and is a block special file
For example:
The code is as follows:
Cd / bin
If test-e. / bash
Then
Echo 'The file already slots'
Else
Echo 'The file does not slots'
Fi
Output:
The file already exists!
In addition, Shell provides three logical operators with (!), or (- o), and non (- a) to connect test conditions, with a priority of: "!" The highest, the second is "- a" and the lowest is "- o". For example:
The code is as follows:
Cd / bin
If test-e. / notFile-o. / bash
Then
Echo 'One file exists at leastmasters'
Else
Echo 'Both dose not slots'
Fi
Output:
One file exists at least!
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