I'm supervising the gpg-agent daemon using s6. Unfortunately, the only official way of getting it to cooperate with a supervision suite is by pre-opening sockets and passing information about them through systemd's LISTEN_* (LISTEN_PID, LISTEN_FDS, LISTEN_FDNAMES) environment variables. It'll only open the sockets itself if you pass an argument that will background it. Thankfully it does not link against libsystemd, and therefore s6 has all the tools needed to fulfill this requirement.
The run script ended up being quite verbose due to all the s6-ipcserver-socketbinder'ing, so I thought of writing a helper. The usage I envisioned would be: socket-helper { name1 /run/name1.socket name2 /run/name2.socket } prog Currently socket-helper is a shell script, as I haven't found a way to generate the unknown number of `s6-ipcserver-socketbinder /path/sock fdmove N 0` using just execline. Is this socket-helper (or an easier-to-implement analogue of it) possible in execline? I know `getpid` allows a one-line implementation of the first environment variable, but I'm at a loss on how to implement the last two.