String Comparisons

Operator	Description
-z string	True if the length of string is zero
-n string	True if the length of string is non-zero
string1 == string2 or string1 = string2	True if the strings are equal; a single = should be used with the test command for POSIX conformance. When used with the [[ command, this performs pattern matching as described above (compound commands).
string1 != string2	True if the strings are not equal
string1 < string2	True if string1 sorts before string2 lexicographically (refers to locale-specific sorting sequences for all alphanumeric and special characters)
string1 > string2	True if string1 sorts after string2 lexicographically