Test: Difference between revisions
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-n string - True if the string length is non-zero. | -n string - True if the string length is non-zero. | ||
<b>Note:<b> | |||
- A blank space must be used between the binary operator and the operands. | |||
- Always use double quotes around the variable names to avoid any word splitting or globbing issues. | |||
Revision as of 18:48, 6 May 2019
The test command (or [[ ]]) is used to test various conditions, or to compare strings.
When comparing strings in Bash you can use the following operators:
string1 = string2 and string1 == string2 - The equality operator returns true if the operands are equal.
- Use the = operator with the test [ command.
- Use the == operator with the [[ command for pattern matching.
string1 != string2 - The inequality operator returns true if the operands are not equal. string1 =~ regex- The regex operator returns true if the left operand matches the extended regular expression on the right. string1 > string2 - The greater than operator returns true if the left operand is greater than the right sorted by lexicographical (alphabetical) order. string1 < string2 - The less than operator returns true if the right operand is greater than the right sorted by lexicographical (alphabetical) order. -z string - True if the string length is zero. -n string - True if the string length is non-zero.
Note:
- A blank space must be used between the binary operator and the operands. - Always use double quotes around the variable names to avoid any word splitting or globbing issues.