Shell's "test" command

Read Catalogue

• Numerical test
• File test
• String test

The test command in the shell is used to check if a condition is true, and it can be tested in three ways, such as numeric values, files, and characters.

• Test equivalent in Shell [] pay attention to the variable with the $ symbol before using the numeric test
• Learn what a shell script must know
• The following author gives only one instance in each test, and the other

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

• Instance

#!/bin/basht1=10t2=10if test $t 1-eq $t 2then        echo "equal" Else        echo "Not Equal" fi

[[Email protected] ~]# sh test1.sh 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

• Instance

#!/bin/bashif [-E./test1.sh]then        echo "This is the file! "Else        echo" This is not a file! "Fi

[[Email protected] ~]# sh test1.sh This is the file!

String Test

parameter	description
=	equals True
!=	Unequal is true
-z String	string length pseudo true
-n string

• Instance

#!/bin/basht1=10t2=10if test T1=t2then        echo "equal" Else        echo "Not Equal" fi

[[Email protected] ~]# sh test1.sh equal

The shell is also provided with (-a), or (-O), non (!) Three logical operators are used to connect test conditions with a priority of: "!" Highest, "-a" followed by, "-O" lowest

• Instance

#!/bin/bashif test-e/test1.sh-o./test.txtthen        echo "are all files" else        echo "one of them is not a file or does not exist" fi

[[Email protected] ~]# sh test1.sh are files

Shell's "test" command