see also: bash, csh, ps, access, execve, faccessat, fork, getpgrp, getpid, getppid, getsid, kill, setegid, seteuid, setfsgid, setfsuid, setgid, setgroups, setresgid, setresuid, setuid, waitpid, euidaccess, initgroups, tcgetpgrp, tcsetpgrp, capabilities, path_resolution, unix