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' The numbers is equal! ' else' The numbers is not equal! ' fi                   

Output Result:

The numbers is equal! 

String test

Parameters	Description
=	Equals is True
!=	Not Equal is true
-Z String	The string length pseudo is True
-N String	True if the string length is not pseudo

Example Demo:

NUM1=num2=if test num1= num2 then' the ' The ' Strings ' isequal! ' else' the strings is not equal! ' fi             

Output Result:

The strings is 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:

/Binif-./bashthen' the file already exists! ' else' The file does not exists! ' fi         

Output Result:

The 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:

/Binif-./-./bashthen' one file exists at least! ' else' Both dose not exists! ' fi           

Output Result:

One file exists at least! 

Shell Test Command