Linux bash not equal operator is expressed with the “-ne” which is the first letter of “not equal”. Also the “! =” is used to express not equal operator.

Is not equal to in bash script?

Following the reference to “Bash Conditional Expressions” will lead you to the description of -ne , which is the numeric inequality operator (“ne” stands for “not equal). By contrast, != is the string inequality operator.

What does $0 mean in shell script?

$0 expands to the name of the shell or shell script. This is set at shell initialization. If bash is invoked with a file of commands, $0 is set to the name of that file.