#!/bin/dash
$0=myname

$0 can not be changed in Dash.

You appear to be trying to assign a new value to $0 in Dash.

Dash does not support this. Write around it, or switch to Bash.

If you instead wanted to compare the value of $0, use a comparison like [ "$0" = "myname" ].

• Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!