Linux Shells by Example

6.1. Comparison Expressions

Comparison expressions match lines where the action is performed if the condition is true. These expressions use relational operators and are used to compare numbers or strings. Table 6.1 provides a list of the relational operators. The value of the expression is 1 if the expression evaluates true, and 0 if false.

6.1.1. Relational operators

Table 6.1. Relational Operators

Operator	Meaning	Example
<	Less than	x < y
<=	Less than or equal to	x <= y
==	Equal to	x == y
!=	Not equal to	x != y
>=	Greater than or equal to	x >= y
>	Greater than	x > y
~	Matched by regular expression	x ~ /y/
!~	Not matched by regular expression	x !~ /y/

Example 6.1.

(The Database) % cat employees Tom Jones 4423 ...