Whether bash sources ~/.bashrc for ssh commands depends on the distro build

For ssh host cmd, sshd runs $SHELL -c cmd. Upstream bash 5.2 only sources ~/.bashrc there if built with SSH_SOURCE_BASHRC, and config-top.h ships that commented out. Its fallback check (isnetconn on stdin) doesn't fire under OpenSSH either, because portable OpenSSH's session.c hardcodes USE_PIPES: fds 0/1/2 of the command are fifos, not sockets. Ubuntu's bash 5.2.21 does source it. A ~/.bashrc with sleep 0.1 added ~100 ms to every exec, even over a ControlMaster (2-4 ms -> 104 ms) and even for ssh host 'sh -c true'. To keep ssh execs fast on Debian/Ubuntu hosts, return early in ~/.bashrc for non-interactive shells: [[ $- == *i* ]] || return.