Shell Test Command

Shell Test Command

The test command in the shell is used to check if a condition is true, and it can be tested in three aspects of numeric, character, and file.

Numerical test

Parameters	Description
-eq	Equals is True
-ne	Not equal to True
-gt	is greater than true
-ge	Greater than or equal to true
-lt	is less than true
-le	is less than or equal to true

Example Demo:

num1=num2=if test $[num1]-eq $[num2]then    '  Two numbers equal!  'else'     Two numbers are not equal!  'fi

Output Result:

Two numbers equal!

The [] in the code performs the basic arithmetic operations, such as:

#!/bin/Basha=5B=6result=$[a+"result is: $ Result"

The result is:

11

String test

Parameters	Description
=	Equals is True
!=	Not Equal is true
-Z String	True if the length of the string is zero
-N String	True if the length of the string is nonzero

Example Demo:

num1="ru1noob"num2="runoob"if test $num 1 = $num 2then    ' two strings equal! ' Else ' Two strings are not equal!       ' fi

Output Result:

Two strings are not equal!

File test

Parameters	Description
-E File name	True if the file exists
-R file name	True if the file exists and is readable
-W file name	True if the file exists and is writable
-X file name	True if the file exists and is executable
-S file name	True if the file exists and has at least one character
-D file name	True if the file exists and is a directory
-F file name	True if the file exists and is a normal file
-C file name	True if the file exists and is a character-specific file
-B file Name	True if the file exists and is a block special file

Example Demo:

CD/binif test-e./bashthen    ' file already exists! ' Else ' File does not exist!       ' fi

Output Result:

File already exists!

In addition, the shell is provided with (-a), or (-O), non (!) Three logical operators are used to connect test conditions with a priority of: "!" Highest, "-a" followed, "-O" the lowest. For example:

CD/binif test-e./notfile-o-E./    bashthen' has a file present! ' Else    ' None of the two files exist ' fi     

Output Result:

There is a file present!

Shell Test Command