test command means Check file types and compare values.

Syntax
test EXPRESSION
test
[ EXPRESSION ]
[ ]
[ OPTION
In man page the describe it
- test – check file types and compare values.
- man test – More details information about test command.
test command in Linux with Examples
$ test 10 -gt 5 && echo "Yes"
Conclusion
test command is the simple the command in Linux. It is the most popular in use terminal Linux check file types and compare values.