hostname$:  awk '$1 ~ $2'
hostname$:  123afdfa ^[0-9a-z]+$
hostname$:  123afdfa ^[0-9a-z]+$
hostname$:  123afdfa /^[0-9a-z]+$/
(nothing printed)
hostname$:  123afdfa "^[0-9a-z]+$"
(nothing printed)


/*
*   my question is why the regular expression enclosed by / or "" doesn't work?
/