credentials(7) Miscellaneous Information Manual credentials(7) credentials - (PID) fork(2). (PID) getpid(2). pid_t ( ). (PIDs) : kill(2) ptrace(2) setpriority(2) setpgid(2) setsid(2) sigqueue(3) waitpid(2). execve(2). (PPID) fork(2). (PPID) getppid(2). pid_t. execve(2). pid_t. getsid(2) getpgrp(2). fork(2) . execve(2). . ( "") ( ) ( "ls | wc" ). setpgid(2). (PID) . . ( ). setsid(2) (PID) setsid(2). . . ( O_NOCTTY open(2)). . . SIGTTIN . TOSTOP ( termios(3)) SIGTTOU . ( control-C) . kill(2) killpg(3) getpriority(2) setpriority(2) ioprio_get(2) ioprio_set(2) waitid(2) waitpid(2). F_GETOWN F_GETOWN_EX F_SETOWN F_SETOWN_EX fcntl(2). . uid_t gid_t ( ). : o . . () getuid(2) (getgid(2)). o . . UNIX . . () geteuid(2) (getegid(2)). o . set-user-ID set-group-ID ( execve(2)). set-user-ID . seteuid(2) setreuid(2) setresuid(2). set-group-ID setegid(2) setregid(2) setresgid(2). () getresuid(2) (getresgid(2)). o ( ). path_resolution(7) . () () . UNIX . setfsuid(2) setfsgid(2). o . . 2.6.4 32 2.6.4 65536 . sysconf(_SC_NGROUPS_MAX) . getgroups(2). fork(2) . execve(2) execve(2). : o ( kill(2)) o ( nice (CPU affinity) /) setpriority(2) sched_setaffinity(2) sched_setscheduler(2) sched_setparam(2) sched_setattr(2) ioprio_set(2) o ( getrlimit(2)) o inotify ( inotify(7)). : setuid(2) ( setgid(2)) () ( ). seteuid(2) ( setegid(2)) () . setfsuid(2) ( setfsgid(2)) () . setreuid(2) ( setregid(2)) () ( ). setresuid(2) ( setresgid(2)) () . setgroups(2) . () () . "dumpable" prctl(2). capabilities(7). POSIX.1. POSIX.1. . /proc/pid/status . proc(5) . POSIX . . NPTL ( setuid(2) setresuid(2)) POSIX . nptl(7) . bash(1) csh(1) groups(1) id(1) newgrp(1) ps(1) runuser(1) setpriv(1) sg(1) su(1) access(2) execve(2) faccessat(2) fork(2) getgroups(2) getpgrp(2) getpid(2) getppid(2) getsid(2) kill(2) setegid(2) seteuid(2) setfsgid(2) setfsuid(2) setgid(2) setgroups(2) setpgid(2) setresgid(2) setresuid(2) setsid(2) setuid(2) waitpid(2) euidaccess(3) initgroups(3) killpg(3) tcgetpgrp(3) tcgetsid(3) tcsetpgrp(3) group(5) passwd(5) shadow(5) capabilities(7) namespaces(7) path_resolution(7) pid_namespaces(7) pthreads(7) signal(7) system_data_types(7) unix(7) user_namespaces(7) sudo(8) 3 . . : . 6.18 8 2026 credentials(7)