Re: [9fans] inequality testing in shell

[erik quanstrom <quanstro@quanstro.net>]

On Sun Jun 14 14:12:13 PDT 2015, nsajko@gmail.com wrote:
> Why doesn't the plan9 test program have features for checking
> inequalities (i.e. greater than etc.)?
> What do you guys do when you want to test for inequality?
>
> Maybe the most convenient way to do that in the shell would be if I
> made two tiny programs, lt & gt which would check their two arguments.

to be more pedantic than necessary, test is not part of the plan 9 shell.
the ~ operator is the way to test for (string) equality or inequality.
! is shell negation, so for non-negative integral x,

~ $x [1-3]	-> x < 4
! ~ $x [1-3]	-> x >= 4

the shell doesn't understand numbers.

outside the shell, hoc or awk are alternatives to test

- erik