After the first command, $_ expands to whatever the last argument to the previous command expanded to. In this case the previous command was : and the only argument is by definition the last. This is how you chain…
: is the null command. Kind of like /bin/true. So : followed by anything exists simply to perform expansion on something. If you fully understand what that means, then you will understand this: $_ is simply “whatever…
After the first command, $_ expands to whatever the last argument to the previous command expanded to. In this case the previous command was : and the only argument is by definition the last. This is how you chain…
: is the null command. Kind of like /bin/true. So : followed by anything exists simply to perform expansion on something. If you fully understand what that means, then you will understand this: $_ is simply “whatever…